Positive electrode slurry composition, positive electrode, and lithium secondary battery comprising same

Abstract

The present invention relates to a positive electrode slurry composition, a positive electrode, and a lithium secondary battery comprising same and, specifically, to a positive electrode slurry composition for a lithium secondary battery, a positive electrode for a lithium secondary battery, and a lithium secondary battery comprising same, the positive electrode slurry composition comprising a positive electrode active material, a film-forming additive, and a solvent, wherein the film-forming additive is a compound represented by chemical formula 1.

Description

Positive electrode slurry composition, positive electrode, and lithium secondary battery including the same

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0087858, filed July 3, 2024, and Korean Patent Application No. 10-2025-0085515, filed June 26, 2025, the entire contents of which are incorporated herein by reference.

[0003]

[0004] Technology field

[0005] The present invention relates to a positive electrode slurry composition, a positive electrode, and a lithium secondary battery including the same, thereby reducing gas generation caused by a side reaction between the positive electrode and an electrolyte.

[0006] As technological development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing, and among these secondary batteries, lithium secondary batteries, which exhibit high energy density and operating potential, long cycle life, and low self-discharge rate, are commercialized and widely used.

[0007] Meanwhile, as the application range of lithium secondary batteries expands to include not only portable power sources for mobile phones, laptop computers, digital cameras, and camcorders, but also medium and large power sources for power tools, electric bicycles, hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs), a high operating voltage is required to achieve high energy density.

[0008] However, when continuously operated under high voltage, not only is the electrolyte depleted due to the oxidation and decomposition reaction between the anode and electrolyte, but the passive film on the electrode surface collapses, causing problems such as gas generation due to electrolyte side reactions and transition metal elution from the anode, resulting in deterioration of the long-life performance of the battery. These problems are aggravated or accelerated by exothermic reactions induced during battery operation.

[0009] Accordingly, there is a need for the development of a lithium secondary battery capable of realizing high energy density by forming a stable passive film on the electrode surface during high-voltage operation, thereby suppressing gas generation due to electrolyte side reactions and the elution of transition metals from the anode.

[0010] One object of the present invention is to solve the above-mentioned problems and to provide an anode slurry composition including a compound capable of forming a highly durable film on the surface of an anode.

[0011] In addition, another object of the present invention is to provide an anode comprising a compound capable of forming a highly durable film on the surface of the anode.

[0012] In addition, another object of the present invention is to provide a lithium secondary battery including the aforementioned positive electrode.

[0013] [1] The present invention provides a positive electrode slurry composition for a lithium secondary battery, which comprises a positive electrode active material, a film-forming additive, and a solvent, wherein the film-forming additive is a compound represented by the following chemical formula 1.

[0014] [Chemical Formula 1]

[0015]

[0016] In the above chemical formula 1,

[0017] L1, L2 and L3 are each independently a direct bond or an alkylene group having 1 to 10 carbon atoms, R1 and R2 are each independently an alkenyl group having 2 to 7 carbon atoms or an alkynyl group having 2 to 7 carbon atoms, R3 is an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 7 carbon atoms, and when both R1 and R2 are alkynyl groups having 2 to 7 carbon atoms, R3 is an alkyl group having 1 to 5 carbon atoms.

[0018] [2] The present invention provides a positive electrode slurry composition for a lithium secondary battery, wherein in the chemical formula 1, in the above [1], L1, L2 and L3 are each independently a direct bond or an alkylene group having 1 to 5 carbon atoms, R1 and R2 are each independently an alkenyl group having 2 to 5 carbon atoms or an alkynyl group having 2 to 5 carbon atoms, and R3 is an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 5 carbon atoms.

[0019] [3] The present invention provides a positive electrode slurry composition for a lithium secondary battery, wherein in the chemical formula 1, in the above [1] or [2], L1, L2 and L3 are each independently an alkylene group having 1 to 3 carbon atoms, R1 and R2 are each independently an alkenyl group having 2 to 5 carbon atoms, and R3 is an alkenyl group having 2 to 5 carbon atoms.

[0020] [4] The present invention provides a positive electrode slurry composition for a lithium secondary battery, wherein in at least one of the above [1] to [3], in the chemical formula 1, L1, L2 and L3 are each independently an alkylene group having 1 to 3 carbon atoms, R1 and R2 are each independently an alkenyl group having 2 to 4 carbon atoms, and R3 is an alkenyl group having 2 to 4 carbon atoms.

[0021] [5] The present invention provides a positive electrode slurry composition for a lithium secondary battery, wherein in at least one of the above [1] to [4], L1, L2 and L3 in the chemical formula 1 are each independently an alkylene group having 1 to 3 carbon atoms, R1 and R2 are each independently an alkynyl group having 2 to 5 carbon atoms, and R3 is an alkyl group having 1 to 3 carbon atoms.

[0022] [6] The present invention provides a positive electrode slurry composition for a lithium secondary battery, wherein in at least one of the above [1] to [5], in the chemical formula 1, L1, L2 and L3 are direct bonds or alkylene groups having 1 to 3 carbon atoms, R1 and R2 are alkynyl groups having 2 to 4 carbon atoms, and R3 is an alkyl group having 1 to 3 carbon atoms.

[0023] [7] The present invention provides a positive electrode slurry composition for a lithium secondary battery, wherein in at least one of the above [1] to [6], the compound represented by the chemical formula 1 is any one of the compounds represented by the following chemical formulas 1A to 1E.

[0024] [Chemical Formula 1A]

[0025]

[0026] [Chemical Formula 1B]

[0027]

[0028] [Chemical Formula 1C]

[0029]

[0030] [Chemical Formula 1D]

[0031]

[0032] [Chemical Formula 1E]

[0033] .

[0034] [8] The present invention provides a positive electrode slurry composition for a lithium secondary battery, wherein, in at least one of the above [1] to [7], the film-forming additive is included in an amount of 0.01 wt% to 10 wt% based on the total solid content weight of the positive electrode slurry composition.

[0035] [9] The present invention provides a positive electrode slurry composition for a lithium secondary battery, wherein, in at least one of [1] to [8], the film-forming additive is included in an amount of 0.01 wt% to 8 wt% based on the total solid content weight of the positive electrode slurry composition.

[0036]

[0010] The present invention provides a positive electrode slurry composition, wherein in at least one of the above [1] to [9], the positive electrode active material includes a compound represented by the following chemical formula 2.

[0037] [Chemical Formula 2]

[0038] Li 1+a Ni x Co y M 1 z M 2 w O2

[0039] In the above chemical formula 2, M 1 is Mn, Al or a combination thereof, and M 2 is at least one selected from the group consisting of Al, Zr, W, Ti, Mg, Ca and Sr, and 0≤a≤0.5, 0 <x<1.0, 0<y≤0.4, 0<z≤0.4, 0≤w≤0.1 이다.

[0040]

[0011] The present invention provides a positive electrode slurry composition for a lithium secondary battery, wherein in at least one of the above [1] to

[0010] , the positive electrode slurry composition for a lithium secondary battery further comprises at least one of a conductive material, a binder, and a thickener.

[0041]

[0012] The present invention provides a positive electrode for a lithium secondary battery, comprising a positive electrode mixture layer including a positive electrode active material and a film-forming additive, wherein the film-forming additive is a compound represented by the following chemical formula 1:

[0042] [Chemical Formula 1]

[0043]

[0044] In the above chemical formula 1, L1, L2 and L3 are each independently a direct bond or an alkylene group having 1 to 10 carbon atoms, R1 and R2 are each independently an alkenyl group having 2 to 7 carbon atoms or an alkynyl group having 2 to 7 carbon atoms, R3 is an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 7 carbon atoms, and when both R1 and R2 are alkynyl groups having 2 to 7 carbon atoms, R3 is an alkyl group having 1 to 5 carbon atoms.

[0045]

[0013] The present invention provides an anode in the above

[0012] , wherein the anode composite layer includes a boron (B)-containing film.

[0046]

[0014] The present invention provides a method for manufacturing a positive electrode for a secondary battery, comprising the steps of: applying a positive electrode slurry composition on a positive electrode current collector; and drying and rolling the positive electrode slurry composition to form a positive electrode mixture layer; wherein the positive electrode slurry composition is the positive electrode slurry composition of claim 1.

[0047]

[0015] The present invention provides a lithium secondary battery including the positive electrode of the above

[0012] , a negative electrode facing the positive electrode, a separator, and an electrolyte.

[0048] As described above, the positive electrode slurry composition for a lithium secondary battery according to the present invention comprises a borate compound having a substituent of a specific structure, thereby suppressing the oxidation and decomposition reaction between the positive electrode and the electrolyte, and producing a positive electrode including a robust boron-containing film capable of suppressing oxygen desorption from the positive electrode.

[0049] In addition, the positive electrode for a lithium secondary battery according to the present invention includes a borate compound having a substituent of a specific structure, thereby forming a strong boron-containing film on the surface of the positive electrode, thereby suppressing an oxidation and decomposition reaction between the positive electrode and the electrolyte.

[0050] In addition, a lithium secondary battery including such a cathode can effectively improve electrochemical performance, such as high-temperature life characteristics and high-temperature storage performance, by suppressing gas generation and transition metal elution from the cathode during operation.

[0051] The terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0052] Hereinafter, the present invention will be described in detail.

[0053] The positive electrode slurry composition for a lithium secondary battery, the positive electrode for a lithium secondary battery, the positive electrode manufacturing method, and the lithium secondary battery according to the present invention comprise at least one or more of the following disclosed configurations, and may comprise any combination between technically possible configurations among the following configurations.

[0054]

[0055] Cathode slurry composition for lithium secondary batteries

[0056] The positive electrode slurry composition for a lithium secondary battery according to the present invention

[0057] It includes a positive electrode active material, a film-forming additive, and a solvent, and the film-forming additive may be a compound represented by the following chemical formula 1.

[0058] [Chemical Formula 1]

[0059]

[0060] In the above chemical formula 1,

[0061] L1, L2 and L3 are each independently a direct bond or an alkylene group having 1 to 10 carbon atoms,

[0062] R1 and R2 are each independently an alkenyl group having 2 to 7 carbon atoms or an alkynyl group having 2 to 7 carbon atoms,

[0063] R3 is an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 7 carbon atoms,

[0064] When both R1 and R2 are alkynyl groups having 2 to 7 carbon atoms, R3 is an alkyl group having 1 to 5 carbon atoms.

[0065]

[0066] (1) Positive electrode active material

[0067] The positive electrode active material of the present invention is a compound capable of reversible intercalation and deintercalation of lithium, and specifically may include a lithium composite metal oxide containing lithium and one or more metals such as cobalt, manganese, nickel, or aluminum.

[0068] Specifically, the positive electrode active material is a lithium-cobalt oxide (e.g., LiCoO2, etc.), a lithium-manganese oxide (e.g., LiMnO2, LiMn2O4, etc.), a lithium-nickel oxide (e.g., LiNiO2, etc.), a lithium-nickel-manganese oxide (e.g., LiNi 1-Y Mn Y O2 (here, 0 <Y<1), LiMn 2-z Ni z O4 (where 0<Z<2), etc.), lithium-nickel-cobalt oxides (e.g., LiNi 1-Y1 Co Y1 O2 (here, 0 <Y1<1) 등), 리튬-망간-코발트계 산화물(예를 들면, LiCo 1-Y2 Mn Y2 O2 (here, 0 <Y2<1), LiMn 2-z1 Co z1O4 (wherein, 0<Z1<2) etc.), lithium-nickel-manganese-cobalt oxides (e.g., Li(Ni p Co q Mn r1 )O2(wherein, 0<p<1, 0<q<1, 0<r1<1, p+q+r1=1) or Li(Ni p1 Co q1 Mn r2 )O4 (wherein, 0<p1<2, 0<q1<2, 0<r2<2, p1+q1+r2=2) etc.), lithium-nickel-cobalt-transition metal (M) oxide (e.g., Li(Ni p2 Co q2 Mn r3 M S2 )O2 (wherein, M is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg, Ti, and Mo, and p2, q2, r3, and s2 are atomic fractions of independent elements, respectively, 0<p2<1, 0<q2<1, 0<r3<1, 0<s2<1, p2+q2+r3+s2=1), and the like, and one or more compounds thereof may be included.

[0069] In order to increase the capacity characteristics and stability of the battery, the positive electrode active material may include at least one selected from the group consisting of lithium-cobalt oxide, lithium-manganese oxide, lithium-nickel-manganese-cobalt oxide represented by the following chemical formula 2, and lithium-nickel-cobalt-transition metal (M) oxide.

[0070] [Chemical Formula 2]

[0071] Li 1+a Ni x Co y M 1 z M 2 w O2

[0072] In the above chemical formula 2,

[0073] M 1 is Mn, Al or a combination thereof,

[0074] M 2 is at least one selected from the group consisting of Al, Zr, W, Ti, Mg, Ca and Sr, and 0≤a≤0.5, 0 <x<1.0, 0<y≤0.4, 0<z≤0.4, 0≤w≤0.1 이다.

[0075] The above 1+a represents the atomic fraction of lithium in the lithium transition metal oxide, and may be 0≤a≤0.5, preferably 0≤a≤0.2, and more preferably 0≤a≤0.1.

[0076] The above x represents the atomic fraction of nickel among the total transition metal elements in the lithium transition metal oxide, and 0 <x<1.0, 구체적으로 0.55<x≤0.98, 더욱 구체적으로는 0.6≤x≤0.98, 보다 더 구체적으로는 0.6≤x≤0.95일 수 있다.

[0077] The above y represents the atomic fraction of cobalt among the total transition metal elements in the lithium transition metal oxide, and 0 <y≤0.4, 구체적으로 0<y≤0.3, 더욱 구체적으로는 0.05≤y≤0.3일 수 있다.

[0078] The above z is M among all transition metal elements in lithium transition metal oxide. 1 Indicates the atomic fraction of an element, 0 <z≤0.4, 바람직하게는 0<z≤0.3, 더 바람직하게는 0.01≤z≤0.3일 수 있다.

[0079] The above w is M among all transition metal elements in lithium transition metal oxide. 2 Indicates the atomic fraction of an element, 0 <w≤0.1, 바람직하게는 0<w≤0.05, 더 바람직하게는 0<w≤0.02이다.

[0080] Specifically, the positive electrode active material may include a lithium composite transition metal oxide having a Ni content of 0.55 atm% or more based on the total number of metal elements excluding lithium, in order to implement a high-capacity battery. More specifically, the positive electrode active material may include Li(Ni 0.6 Mn 0.2 Co 0.2 )O2, Li(Ni) 0.6 Mn 0.3 Co 0.1 )O2, Li(Ni) 0.7 Mn 0.15 Co 0.15 )O2, Li(Ni 0.7 Mn 0.2 Co 0.1 )O2, Li(Ni 0.8 Mn 0.1 Co 0.1 )O2, Li(Ni 0.8 Co 0.15 Al 0.05 )O2, Li(Ni 0.86 Mn 0.07 Co 0.05 Al 0.02 )O2 or Li(Ni 0.90 Mn 0.05 Co 0.05 ) may include lithium composite transition metal oxides such as O2.

[0081] The above-mentioned positive electrode active material may be included in an amount of 80 to 98 wt%, more specifically 85 to 98 wt%, based on the total weight of the solid content included in the positive electrode slurry composition. When the positive electrode active material is included in the above range, excellent capacity characteristics can be secured, and excellent flowability, conductivity, or physical properties of the positive electrode slurry composition can be obtained.

[0082]

[0083] (2) Film-forming additives

[0084] The positive electrode slurry composition of the present invention may include a film-forming additive so that a boron-containing solid film can be formed on the positive electrode surface.

[0085] The above film-forming additive may be a compound represented by the following chemical formula 1.

[0086] [Chemical Formula 1]

[0087]

[0088] In the above chemical formula 1,

[0089] L1, L2 and L3 are each independently a direct bond or an alkylene group having 1 to 10 carbon atoms,

[0090] R1 and R2 are each independently an alkenyl group having 2 to 7 carbon atoms or an alkynyl group having 2 to 7 carbon atoms,

[0091] R3 is an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 7 carbon atoms,

[0092] When both R1 and R2 are alkynyl groups having 2 to 7 carbon atoms, R3 is an alkyl group having 1 to 5 carbon atoms.

[0093]

[0094] The compound represented by the above chemical formula 1 can form a stable film that can suppress side reactions with the electrolyte on the surface of the positive electrode by being directly introduced together with the positive electrode active material during the positive electrode coating process. In particular, the compound represented by the chemical formula 1 contains a boron element, which is a Lewis base, in its structure, so that it can form an anion of a lithium salt, such as PF6. - It is possible to prevent further decomposition of boron and suppress HF generation through this. In addition, since the oxygen arranged at the α-position of the boron element has an unshared electron pair, it can be stably adsorbed to the positive electrode, thereby forming a film with enhanced Li ion characteristics. In this way, the compound represented by chemical formula 1 can form a strong film on the surface of the positive electrode, thereby preventing side reactions at the interface between the positive electrode and the electrolyte, suppressing the oxidative decomposition reaction of the electrolyte, and suppressing oxygen desorption and transition metal elution from the positive electrode active material. Therefore, it is possible to effectively improve electrochemical performance, such as high-temperature life characteristics and high-temperature storage performance, of a lithium secondary battery.

[0095]

[0096] Meanwhile, in the above chemical formula 1, L1 may be a direct bond or an alkylene group having 1 to 7 carbon atoms, or a direct bond or an alkylene group having 1 to 5 carbon atoms, or an alkylene group having 1 to 3 carbon atoms, or an alkylene group having 1 or 2 carbon atoms. Specifically, L1 may be a methylene group.

[0097] In the above chemical formula 1, L2 may be a direct bond or an alkylene group having 1 to 7 carbon atoms, or a direct bond or an alkylene group having 1 to 5 carbon atoms, or an alkylene group having 1 to 3 carbon atoms, or an alkylene group having 1 or 2 carbon atoms. Specifically, L2 may be a methylene group.

[0098] In the above chemical formula 1, L3 may be a direct bond or an alkylene group having 1 to 7 carbon atoms, or a direct bond or an alkylene group having 1 to 5 carbon atoms, or a direct bond or an alkylene group having 1 to 3 carbon atoms. Specifically, L3 may be a direct bond or a methylene group.

[0099] In addition, in the above chemical formula 1, R1 may be an alkenyl group having 2 to 5 carbon atoms or an alkynyl group having 2 to 5 carbon atoms, or an alkenyl group having 2 to 4 carbon atoms or an alkynyl group having 2 to 4 carbon atoms, or an alkenyl group having 2 to 3 carbon atoms or an alkynyl group having 2 to 3 carbon atoms. Preferably, R1 may be a vinyl group which is an alkenyl group having 2 carbon atoms or a propargyl group which is an alkynyl group having 2 carbon atoms.

[0100] In addition, in the above chemical formula 1, R2 may be an alkenyl group having 2 to 5 carbon atoms or an alkynyl group having 2 to 5 carbon atoms, or an alkenyl group having 2 to 4 carbon atoms or an alkynyl group having 2 to 4 carbon atoms, or an alkenyl group having 2 to 3 carbon atoms or an alkynyl group having 2 to 3 carbon atoms. Preferably, R1 may be a vinyl group which is an alkenyl group having 2 carbon atoms or a propargyl group which is an alkynyl group having 2 carbon atoms.

[0101] In addition, in the above chemical formula 1, R3 may be an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, or an alkyl group having 1 to 3 carbon atoms or an alkenyl group having 2 to 4 carbon atoms. Specifically, R3 may be a vinyl group, which is a methyl group, an ethyl group, a propyl group, or an alkenyl group having 2 carbon atoms.

[0102] In particular, in the above chemical formula 1, when both R1 and R2 are alkynyl groups, R3 may be an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 3 carbon atoms.

[0103] Meanwhile, in the above chemical formula 1, L1, L2, L3, R1, R2 and R3 can be combined with each other without limitation. Specifically, in the above chemical formula 1, L1, L2 and L3 are each independently a direct bond or an alkylene group having 1 to 5 carbon atoms, R1 and R2 are each independently an alkenyl group having 2 to 5 carbon atoms or an alkynyl group having 2 to 5 carbon atoms, and R3 can be an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 5 carbon atoms.

[0104] In addition, in the above chemical formula 1, L1, L2 and L3 are each independently an alkylene group having 1 to 3 carbon atoms, R1 and R2 are each independently an alkenyl group having 2 to 5 carbon atoms, and R3 may be an alkenyl group having 2 to 5 carbon atoms.

[0105] In addition, in the above chemical formula 1, L1, L2 and L3 are each independently an alkylene group having 1 to 3 carbon atoms, R1 and R2 are each independently an alkenyl group having 2 to 4 carbon atoms, and R3 may be an alkenyl group having 2 to 4 carbon atoms.

[0106] In addition, in the above chemical formula 1, L1, L2 and L3 are each independently an alkylene group having 1 to 3 carbon atoms, R1 and R2 are each independently an alkynyl group having 2 to 5 carbon atoms, and R3 may be an alkyl group having 1 to 3 carbon atoms.

[0107] In addition, in the above chemical formula 1, L1, L2 and L3 may be direct bonds or alkylene groups having 1 to 3 carbon atoms, R1 and R2 may be alkynyl groups having 2 to 4 carbon atoms, and R3 may be an alkyl group having 1 to 3 carbon atoms.

[0108] More specifically, it is preferable that the compound represented by Chemical Formula 1 of the present invention includes any one of the compounds represented by Chemical Formulas 1A to 1E below.

[0109] Compounds represented by the following chemical formulae 1A and 1C contain three double bond terminal groups, and thus, although their reaction rate is lower than that of the compound represented by the above chemical formula 3, they can be reduced more stably and form a uniform film. In addition, compounds represented by the following chemical formulae 1B or 1D contain two triple bond terminal groups, and thus, they can form a stable and uniform film by controlling the reaction rate. In addition, compounds represented by the following chemical formula 1E contain both triple bond terminal groups and double bond terminal groups in their structure, and thus, they can form a stable film while controlling the reaction rate:

[0110] [Chemical Formula 1A]

[0111]

[0112] [Chemical Formula 1B]

[0113]

[0114] [Chemical Formula 1C]

[0115]

[0116] [Chemical Formula 1D]

[0117]

[0118] [Chemical Formula 1E]

[0119]

[0120]

[0121] Meanwhile, when the film-forming additive includes a compound represented by the following chemical formula 3 in which all terminal groups are substituted with a triple bond structure (propargyl group) having a fast reaction rate, the reduction reaction rate of the film-forming additive increases excessively during operation, causing a rapid radical reaction due to electron cloud aggregation within the propargyl group, and thereby increasing random reactions, which may result in the formation of an uneven film on the surfaces of the positive and negative electrodes. Consequently, the long-term durability of the lithium secondary battery is poor.

[0122] [Chemical Formula 3]

[0123]

[0124] In addition, when a compound represented by the following chemical formula 4 or 5 containing at least one nitrile group (-CN) at the terminal is included as a film-forming additive, it becomes difficult to induce film formation by an oxidation reaction as the nitrile group having high oxidation stability is adsorbed to the positive electrode active material. That is, in the case of the compound represented by the following chemical formula 4 or 5, compared to the compound represented by the above chemical formula 1 containing a vinyl group and / or a propargyl group as a terminal group, it has high oxidation stability, making it difficult to induce an oxidation film-forming reaction, and also, due to the film-forming mechanism based on the adsorption of the cyanide functional group, there is a disadvantage in that it is difficult to form a film having excellent coverage characteristics through a chain reaction (propagation).

[0125] [Chemical Formula 4]

[0126]

[0127] [Chemical Formula 5]

[0128]

[0129]

[0130] Meanwhile, the film-forming additive may be included in an amount of 0.01 wt% or more, 0.05 wt% or more, 0.1 wt% or more, 0.3 wt% or more, 0.5 wt% or more, 0.7 wt% or more, 0.9 wt% or more, or 1.0 wt% or more, based on the total weight of the solid content of the positive electrode slurry composition, and may also be included in an amount of 10 wt% or less, 8 wt% or less, 6 wt% or less, 5 wt% or less, 4 wt% or less, 3 wt% or less, or 2 wt% or less. When the content of the film-forming additive satisfies the above range, the film-forming additive can form a solid film on the surface of the positive electrode while preventing side reactions, thereby suppressing the oxidative decomposition reaction of the positive electrode and the electrolyte, reducing gas generation, and suppressing oxygen desorption from the positive electrode. The above numerical ranges can be combined with each other without limitation, and specifically can be included as 0.01 wt% to 10 wt%, 0.01 wt% to 8 wt%, or 0.1 wt% to 5 wt%. That is, when the content of the film-forming additive is 0.01 wt% or more, a solid film can be formed on the positive electrode surface during the battery operation time, and when it is 10 wt% or less, side reactions due to the film-forming additive can be prevented, and a thick film can be formed on the positive electrode surface, preventing an increase in resistance.

[0131]

[0132] (3) Solvent

[0133] In the positive electrode slurry composition of the present invention, the solvent may be an organic solvent and / or an aqueous solvent commonly used in the relevant technical field.

[0134] Specifically, the organic solvent may be at least one of N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), isopropyl alcohol, acetone, methoxy propyl acetate, butyl acetate, glycol acid, butyl ester, butyl glycol, methylalkylpolysiloxane, alkylbenzene, propylene glycol, xylene, monophenyl glycol, aralkyl-modified methylalkylpolysiloxane, polyether-modified dimethylpolysiloxane copolymer, polyether-modified dimethylpolysiloxane copolymer, polyacrylate, alkylbenzene, diisobutyl ketone, organic-modified polysiloxane, butanol, isobutanol, modified polyacrylate, modified polyurethane, and polysiloxane-modified polymer. In addition, the aqueous solvent may include water.

[0135] The amount of the above solvent used is not particularly limited and can be adjusted to an extent that the positive electrode slurry composition has an appropriate viscosity considering the coating thickness of the positive electrode mixture layer, manufacturing yield, workability, etc.

[0136]

[0137] Meanwhile, the positive electrode slurry composition for a lithium secondary battery of the present invention may optionally additionally include at least one of a conductive agent, a binder, and a thickener, as needed.

[0138]

[0139] (4) Challenge

[0140] Specifically, the conductive material is used to provide conductivity to the electrode, and in the battery to be formed, as long as it does not cause a chemical change and has electronic conductivity, it can be used without any particular limitation. Specific examples of the conductive material include carbon black such as carbon black, acetylene black (or Denka black), Ketjen black, channel black, furnace black, lamp black, or thermal black; graphite powder such as natural graphite, artificial graphite, or graphite with a highly developed crystal structure; conductive fibers such as carbon fibers or metal fibers; conductive powders such as fluorocarbon powder, aluminum powder, or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; polyphenylene derivatives, etc., and one of these may be used alone or a mixture of two or more may be used.

[0141] The conductive agent may be included in an amount of 0.1 to 10.0 wt%, preferably 1.0 to 8.0 wt%, based on the total weight of solids included in the positive electrode slurry composition. When the content of the conductive agent satisfies the above range, the conductivity of the positive electrode can be improved and the flexibility of the positive electrode can be prevented from deteriorating.

[0142]

[0143] (5) Binder

[0144] The binder serves to improve adhesion between positive electrode active material particles and adhesion between the positive electrode active material and the current collector. Examples of such binders include: a fluororesin binder including polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE); a rubber binder including styrene butadiene rubber (SBR), acrylonitrile-butadiene rubber, and styrene-isoprene rubber; a cellulose binder including carboxyl methyl cellulose (CMC), starch, hydroxy propyl cellulose, and regenerated cellulose; a polyalcohol binder including polyvinyl alcohol; a polyolefin binder including polyethylene and polypropylene; a polyimide binder; and a polyester binder. And one type of silane binder alone or a mixture of two or more types may be used.

[0145] The above binder may be included in the positive electrode mixture layer at 0.1 to 15 wt%, preferably 0.1 to 10 wt%, based on the total solid content of the positive electrode slurry composition. When the content of the binder is at the above-described level, sufficient binding force between the positive electrode active material, the positive electrode current collector, etc. can be secured, while preventing a decrease in the capacity of the positive electrode.

[0146]

[0147] (6) Thickener

[0148] In addition, the thickener can provide appropriate viscosity to the positive electrode slurry composition to ensure the stability of the positive electrode slurry composition, and can improve surface defects by alleviating the re-agglomeration phenomenon of solid components when coating the positive electrode slurry composition on a positive electrode current collector.

[0149] The thickener may include carboxymethyl cellulose (CMC).

[0150] The thickener may be included in an amount of 0.5 wt% to 5 wt% based on the total weight of the solid content of the positive electrode slurry composition. If the content of the thickener is less than 0.5 wt%, the viscosity of the positive electrode slurry composition is low and flows like water, making it impossible to coat the positive electrode slurry composition on the positive electrode current collector. If the content of the thickener exceeds 5 wt%, the viscosity is high and becomes stiff, making it difficult to form a uniform coating layer.

[0151] Meanwhile, the viscosity of the positive electrode slurry composition of the present invention is not particularly limited, and may vary depending on the content of solids in the composition. However, considering the phase stability of the positive electrode slurry composition and the ease of the coating process, it may be 1000 cP or more or 4500 cP or more at 25°C.

[0152]

[0153] anode

[0154] Additionally, the present invention includes a positive electrode, specifically a positive electrode for a lithium secondary battery.

[0155] The above anode may include a cathode mixture layer, and the cathode mixture layer may be formed, for example, from the cathode slurry composition described above.

[0156] Additionally, the positive electrode active material layer may include a positive electrode active material and a film-forming additive.

[0157] The positive electrode active material may be included in the positive electrode composite layer in an amount of 80 wt% to 98 wt%, more specifically 85 wt% to 98 wt%.

[0158] The above film-forming additive may be a compound represented by the above chemical formula 1.

[0159] Descriptions of other positive electrode active materials and film-forming additives overlap with those described above, so they are omitted.

[0160] Additionally, the positive electrode active material layer may optionally further include a binder, a conductive agent, and / or a thickener, together with the positive electrode active material and the film-forming additive.

[0161] When the binder is included in the positive electrode mixture layer, the binder may be included in the positive electrode mixture layer in an amount of 0.1 wt% to 15 wt%, specifically 0.1 wt% to 10 wt%.

[0162] When the conductive material is included in the positive electrode mixture layer, the conductive material may be included in the positive electrode mixture layer in an amount of 0.1 wt% to 10.0 wt%, preferably 1.0 wt% to 8.0 wt%.

[0163] When the thickener is included in the positive electrode mixture layer, the thickener may be included in the positive electrode mixture layer at 0.5 wt% to 5 wt%.

[0164] In addition, the description of the above binder, conductive agent, and thickener overlaps with the above-mentioned content, so its description is omitted.

[0165] Meanwhile, the thickness of the positive electrode composite layer may be 50 µm to 500 µm, specifically 100 µm to 300 µm.

[0166]

[0167] Specifically, the positive electrode of the present invention may include a boron (B) and oxygen-containing film disposed on a portion of the surface or the entire surface of the positive electrode mixture layer. Specifically, during the formation process, an oxygen component having an unshared electron pair in the compound represented by the above chemical formula 1, which is a film-forming additive, can be stably adsorbed to the positive electrode, thereby forming a boron and oxygen-containing film with enhanced Li ion characteristics. In particular, the boron component included in the compound represented by the above chemical formula 1 can form an anion of a lithium salt, for example, PF6. - By reacting with the anion, it is possible to prevent further decomposition of the anion and suppress the induction of HF through this, thereby preventing the film deterioration phenomenon.

[0168] When the total content of the boron (B)-containing film satisfies the above range, high thermal safety of the positive electrode active material can be secured, and the effect of improving high-temperature life characteristics and resistance increase rate can be obtained.

[0169]

[0170] The above positive electrode may further include a positive electrode current collector. Specifically, the positive electrode composite layer may be disposed on at least one side, specifically one side or both sides, of the positive electrode current collector.

[0171] Meanwhile, the positive electrode current collector is not particularly limited as long as it is conductive and does not cause chemical changes in the battery, and for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. can be used.

[0172] In addition, the thickness of the positive electrode current collector is not particularly limited and can be set to an appropriate range considering the mechanical strength of the positive electrode, productivity, or battery capacity. For example, the thickness of the positive electrode current collector can typically be 3 μm to 500 μm. In addition, the positive electrode current collector can form fine irregularities on the surface of the positive electrode current collector to increase the adhesive strength of the positive electrode material. For example, it can be used in various forms such as a film, sheet, foil, net, porous body, foam, or non-woven fabric.

[0173]

[0174] Meanwhile, the positive electrode of the present invention can be manufactured according to a positive electrode manufacturing method known in the art. For example, the positive electrode of the present invention can be manufactured by a positive electrode manufacturing method including the steps of preparing a positive electrode slurry composition, then applying the positive electrode slurry composition onto a positive electrode current collector; and drying and rolling the positive electrode slurry composition to form a positive electrode mixture layer. Alternatively, the positive electrode of the present invention can be manufactured by a positive electrode manufacturing method including the steps of casting the positive electrode slurry composition onto a separate support; and laminating a positive electrode mixture layer film obtained by peeling the support onto a positive electrode current collector.

[0175] Specifically, in the present invention

[0176] A step of coating a cathode slurry composition on a cathode current collector; and

[0177] A step of forming a positive electrode mixture layer by drying and then rolling the positive electrode slurry composition;

[0178] The above positive electrode slurry composition provides a method for manufacturing a positive electrode for a secondary battery, which is the positive electrode slurry composition of the present invention.

[0179] According to the method for manufacturing a positive electrode for a secondary battery, since a film-forming additive is introduced into the positive electrode slurry composition in the positive electrode mixture layer manufacturing step, a more smooth positive electrode film can be formed compared to when the film-forming additive is added to a non-aqueous electrolyte and then introduced into the positive electrode. Therefore, the positive electrode and secondary battery manufactured through the method for manufacturing the positive electrode can have excellent high-temperature cycle life performance and high-temperature storage performance.

[0180]

[0181] The drying temperature may be 80 to 250°C.

[0182]

[0183] lithium secondary battery

[0184] A lithium secondary battery according to the present invention may include a positive electrode, a negative electrode, a separator, and an electrolyte according to the present invention.

[0185] Meanwhile, since the description of the constituent materials and manufacturing method of the positive electrode of the present invention overlaps with the above-mentioned content, the description thereof is omitted, and other constituent elements are described below.

[0186]

[0187] (1) Cathode

[0188] The above cathode may be opposite to the above anode.

[0189] The negative electrode used in the lithium secondary battery of the present invention may include a negative electrode composite layer including a negative electrode active material and a conductive material.

[0190] The above negative electrode active material may include at least one selected from the group consisting of lithium metal, a carbon material capable of reversibly intercalating / deintercalating lithium ions, a metal or an alloy of these metals and lithium, a metal composite oxide, a material capable of doping and dedoping lithium, and a transition metal oxide.

[0191] As the carbon material capable of reversibly intercalating / deintercalating the lithium ions, any carbon-based negative electrode active material commonly used in lithium-ion secondary batteries can be used without particular limitation, and representative examples thereof include crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of the amorphous carbon include soft carbon (low-temperature calcined carbon), hard carbon, mesophase pitch carbide, calcined coke, etc.

[0192] As the above metal or an alloy of these metals with lithium, a metal selected from the group consisting of Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al and Sn or an alloy of these metals with lithium may be used.

[0193] The above metal composite oxides include PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, Bi2O5, Li x Fe2O3(0≤x≤1), Li x WO2(0≤x≤1) and Sn x Me 1-x Me' y O z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, elements of group 1, 2, and 3 of the periodic table, halogens; 0 <x≤1; 1≤y≤3; 1≤z≤8) 로 이루어진 군에서 선택되는 것이 사용될 수 있다.

[0194] Materials capable of doping and dedoping the above lithium include Si, SiC, and SiO. x(0 <x<2), Si-Y 합금(상기 Y는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Si은 아님), Sn, SnO2, Sn-Y(상기 Y는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Sn은 아님) 등을 들 수 있고, 또한 이들 중 적어도 하나와 SiO2를 혼합하여 사용할 수도 있다. 상기 원소 Y로는 Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ge, P, As, Sb, Bi, S, Se, Te, Po 및 이들의 조합으로 이루어진 군에서 선택될 수 있다.

[0195] Examples of the above transition metal oxides include lithium-containing titanium composite oxide (LTO), vanadium oxide, and lithium vanadium oxide.

[0196] According to one embodiment, the negative electrode active material of the present invention can be used by including a carbon-based negative electrode active material or a silicon-based negative electrode active material together with the carbon-based negative electrode active material.

[0197] The above negative electrode active material may be included in an amount of 80 wt% to 99 wt% based on the total weight of the negative electrode composite layer. When the content of the negative electrode active material satisfies the above range, excellent capacity characteristics and electrochemical characteristics can be obtained.

[0198] The conductive material may be included in the negative electrode mixture layer at about 0.01 to 2.0 wt%, specifically 0.01 to 1.5 wt%, and more specifically 0.01 to 1.0 wt%, based on the total weight of the negative electrode mixture layer. When the content of the conductive material is 0.01 wt% or more, conductivity between active materials can be sufficiently secured, and when the content of the conductive material is 2.0 wt% or less, the content of the negative electrode active material included in the negative electrode mixture layer can be increased, thereby manufacturing a lithium secondary battery capable of securing excellent high capacity.

[0199] The above negative electrode composite layer may further include a binder.

[0200] The above binder is a component that assists in bonding between a conductive material, an active material, or a current collector, and examples of such binders include a fluororesin binder including polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE); a rubber binder including styrene butadiene rubber (SBR), acrylonitrile-butadiene rubber, and styrene-isoprene rubber; a cellulose binder including carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, and regenerated cellulose; a polyalcohol binder including polyvinyl alcohol; a polyolefin binder including polyethylene and polypropylene; a polyimide binder; a polyester binder; and a silane binder.

[0201] The above binder may be included in the negative electrode composite layer at 0.1 to 15.0 wt%, preferably 0.1 to 10.0 wt%, based on the total weight of the negative electrode composite layer.

[0202]

[0203] The above negative electrode may further include a negative electrode current collector. Specifically, the negative electrode composite layer may be disposed on the negative electrode current collector.

[0204] The negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used. In addition, the negative electrode current collector can typically have a thickness of 3 ㎛ to 500 ㎛, and like the positive electrode current collector, fine unevenness can be formed on the surface of the current collector to strengthen the bonding strength of the negative electrode active material. For example, it can be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric, etc.

[0205]

[0206] Meanwhile, the negative electrode can be manufactured according to a negative electrode manufacturing method known in the art. For example, the negative electrode can be manufactured by dissolving or dispersing a carbon-based active material, a negative electrode conductive material, and optionally a binder in a solvent, applying a negative electrode slurry prepared by coating the negative electrode slurry on a negative electrode current collector, rolling, and drying the same to form a negative electrode mixture layer, or by casting the negative electrode slurry on a support, then peeling off the support, and laminating the obtained negative electrode mixture layer as a film on a negative electrode current collector.

[0207] The solvent may be a solvent generally used in the relevant technical field, and may include dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, or water, and one of these may be used alone or a mixture of two or more thereof. The amount of the solvent used may be adjusted to an extent that the negative electrode slurry has an appropriate viscosity, taking into consideration the coating thickness of the negative electrode composite, manufacturing yield, workability, etc., and is not particularly limited.

[0208]

[0209] (2) Separator

[0210] The above separator may be interposed between the positive electrode and the negative electrode.

[0211] The above separator separates the negative electrode and the positive electrode and provides a passage for the movement of lithium ions. If it is a separator commonly used in lithium secondary batteries, it can be used without any special restrictions. In particular, it is preferable that it has low resistance to the movement of lithium salt ions and excellent electrolyte absorption capacity.

[0212] Specifically, a porous polymer film, for example, a porous polymer film made of a polyolefin 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. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc. may be used. In addition, a coated separator containing a ceramic component or a polymer material may be used to secure heat resistance or mechanical strength, and may optionally be used in a single-layer or multi-layer structure.

[0213]

[0214] (3) Electrolyte

[0215] The electrolyte included in the lithium secondary battery according to the present invention may be a non-aqueous electrolyte. Specifically, the non-aqueous electrolyte may include a lithium salt, a non-aqueous organic solvent, and an additive.

[0216] (3-1) Lithium salt

[0217] First, the lithium salt can be used without limitation as an electrolyte for lithium secondary batteries, for example, Li as a cation. + , and the anion is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , B 10 Cl 10 - , AlCl4 - , AlO4 - , PF6 - , CF3SO3 - , CH3CO2 - , CF3CO2 - , AsF6 - , SbF6 - , CH3SO3 - , (CF3CF2SO2)2N - , (CF3SO2)2N - , (FSO2)2N - , BF2C2O4 - , BC4O8 - , PF4C2O4 - , PF2C4O8 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , C4F9SO3 - , CF3CF2SO3 - , CF3CF2(CF3)2CO -, (CF3SO2)2CH - , CF3(CF2)7SO3 - and SCN - At least one selected from the group consisting of

[0218] Specifically, the lithium salt is LiCl, LiBr, LiI, LiBF4, LiClO4, LiB 10 Cl 10 , LiAlCl4, LiAlO4, LiPF6, LiCF3SO3, LiCH3CO2, LiCF3CO2, LiAsF6, LiSbF6, LiCH3SO3, LiN(SO2F)2(Lithium bis(fluorosulfonyl)imide, LiFSI), LiN(SO2CF2CF3)2(lithium bis(pentafluoroethanesulfonyl)imide, LiBETI), and LiN(SO2CF3)2(lithium bis(trifluoromethane sulfonyl)imide, LiTFSI), and specifically, LiBF4, LiPF6, LiN(SO2F)2(lithium bis(fluorosulfonyl)imide, LiFSI), LiN(SO2CF2CF3)2(lithium bis(pentafluoroethanesulfonyl)imide, LiBETI), and LiN(SO2CF3)2(lithium It may include at least one from the group consisting of bis(trifluoromethane sulfonyl)imide, LiTFSI). In addition to these, lithium salts commonly used in the electrolyte of lithium secondary batteries may be used without limitation.

[0219] The above lithium salt can be appropriately changed within a commonly usable range, but in order to obtain an optimal effect of forming a film for preventing corrosion on the electrode surface, it can be included in the electrolyte at a concentration of 0.8 M to 3.0 M, specifically, at a concentration of 1.0 M to 2.0 M, and preferably at a concentration of 1.0 M to 1.8 M.

[0220] When the concentration of the lithium salt is within the above range, the viscosity of the non-aqueous electrolyte can be controlled to achieve optimal impregnation, and the mobility of lithium ions can be improved, thereby improving the capacity characteristics and cycle characteristics of the lithium secondary battery.

[0221]

[0222] (3-2) Non-aqueous organic solvent

[0223] In addition, the description of the non-aqueous organic solvent is as follows.

[0224] As the above non-aqueous organic solvent, various organic solvents commonly used in non-aqueous electrolytes can be used without limitation, and there is no limitation on the type of the solvent as long as decomposition due to oxidation reactions, etc. during the charge / discharge process of the secondary battery can be minimized and the desired characteristics can be exhibited together with additives.

[0225] Specifically, the non-aqueous organic solvent may include at least one of a cyclic carbonate-based organic solvent and a linear carbonate-based organic solvent to secure high ionic conductivity.

[0226] The above cyclic carbonate-based organic solvent is a high-viscosity organic solvent that has a high dielectric constant and thus facilitates the dissociation of lithium salts in a non-aqueous electrolyte. As a specific example, the organic solvent may include at least one organic solvent selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and vinylene carbonate, and among these, at least one of ethylene carbonate (EC) and propylene carbonate (PC) may be included.

[0227] The above linear carbonate-based organic solvent is an organic solvent having low viscosity and low dielectric constant, and specific examples thereof may include at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate (EMC), methylpropyl carbonate, and ethylpropyl carbonate, and specifically may include at least one of dimethyl carbonate, ethylmethyl carbonate, and diethyl carbonate.

[0228] In the present invention, in order to secure high ionic conductivity, a cyclic carbonate-based organic solvent and a linear carbonate-based organic solvent may be mixed and used as the non-aqueous organic solvent. At this time, the cyclic carbonate-based organic solvent and the linear carbonate-based organic solvent may be mixed and used in a volume ratio of 10:90 to 50:50, or may be mixed and used in a volume ratio of 10:90 to 40:60.

[0229] If necessary, the non-aqueous organic solvent may additionally include a linear ester organic solvent having a lower melting point and higher stability at high temperatures than the cyclic carbonate organic solvent.

[0230] Specific examples of the linear ester organic solvent include at least one organic solvent selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate, and preferably at least one of ethyl propionate and propyl propionate.

[0231] Meanwhile, the remainder of the non-aqueous electrolyte of the present invention, excluding the lithium salt and additives, may all contain a non-aqueous organic solvent unless otherwise specified.

[0232]

[0233] (3-3) Additives

[0234] Next, the non-aqueous electrolyte of the present invention may include an additive to form a solid film on the surface of the negative electrode, thereby preventing the non-aqueous electrolyte from decomposing in a high-power environment and causing the negative electrode to collapse, and at the same time improving low-temperature high-rate discharge characteristics, high-temperature stability, overcharge prevention, and suppression of battery expansion at high temperatures.

[0235] The above additive may further include, as specific examples, at least one selected from the group consisting of a cyclic carbonate compound, a fluorine-based cyclic carbonate compound, a sultone-based compound, a sulfate-based compound, a phosphate-based compound, a nitrile-based compound, a benzene-based compound, an amine-based compound, and a silane-based compound.

[0236] The cyclic carbonate compound may include vinylene carbonate (VC) or vinylethylene carbonate. The cyclic carbonate compound may be included in an amount of 1.0 wt% to 10 wt%, specifically 1.0 wt% to 5.0 wt%, of the total weight of the non-aqueous electrolyte. When the content of the cyclic carbonate compound satisfies the above range, the low-temperature output of the battery and the high-temperature storage characteristics and high-temperature lifespan characteristics can be effectively improved while suppressing side reactions.

[0237] In addition, the fluorinated cyclic carbonate compound may include fluoroethylene carbonate (FEC). The fluoroethylene carbonate (FEC) forms a strong film including a polymer component on the surface of the negative electrode, thereby minimizing damage to the SEI film during high-voltage charge / discharge, thereby preventing deterioration of the negative electrode. The fluorinated cyclic carbonate compound may be included in an amount of 500 to 1,000 parts by weight based on 100 parts by weight of the total content of lithium difluorophosphate (LiDFP) and hexamethylene diisocyanate. When the content of the fluorinated cyclic carbonate compound satisfies the above range, side reactions due to additives that remain without being decomposed are prevented, while forming a strong film on the surfaces of the positive and negative electrodes, thereby effectively preventing deterioration of the positive and negative electrodes during high-voltage charge and high-temperature storage.

[0238] In addition, the sultone-based compound may include at least one compound selected from the group consisting of 1,3-propane sultone (PS), 1,4-butane sultone, ethene sultone, 1,3-propene sultone (PRS), 1,4-butene sultone, and 1-methyl-1,3-propene sultone, and preferably may include 1,3-propane sultone (PS). The sultone-based compound forms a stable SEI film by a reduction reaction on the surface of the negative electrode, thereby preventing side reactions between the negative electrode and the electrolyte at high temperatures, thereby suppressing gas generation, and implementing an effect of increasing durability during high-temperature storage. The sultone-based compound may be included in an amount of 1.0 wt% to 10 wt%, specifically 1.0 wt% to 5.0 wt%, of the total weight of the non-aqueous electrolyte. When the content of the above-mentioned sulphonic compound satisfies the above range, a strong film is formed on the surfaces of the positive and negative electrodes, thereby effectively preventing deterioration of the positive and negative electrodes during high-voltage charging and high-temperature storage.

[0239] In addition, the sulfate-based compound may include ethylene sulfate (Esa), trimethylene sulfate (TMS), or methyl trimethylene sulfate (MTMS). The sulfate-based compound may be included in an amount of 0.01 to 10 wt%, specifically 0.05 to 5.0 wt%, of the total weight of the non-aqueous electrolyte. When the content of the sulfate-based compound satisfies the above range, side reactions within the electrolyte can be suppressed during charge / discharge of the battery, a robust SEI film can be formed, and an excellent life-cycle characteristic improvement effect can be achieved.

[0240] The phosphate-based compound may include at least one compound selected from the group consisting of lithium difluoro(bisoxalato)phosphate, lithium difluorophosphate (LiDFP), tris(trimethylsilyl)phosphate, tris(2,2,2-trifluoroethyl)phosphate, and tris(trifluoroethyl)phosphate. The phosphate-based compound may be included in an amount of 0.01 to 10 wt%, specifically 0.05 to 5.0 wt%, based on the total weight of the non-aqueous electrolyte. When the content of the phosphate-based compound satisfies the above range, a robust SEI film is formed, thereby improving the low-temperature output of the battery and improving the high-temperature storage characteristics and high-temperature lifespan characteristics.

[0241] In addition, the nitrile compound may include at least one compound selected from the group consisting of succinonitrile, hexane tri-cyanide (HTCN), adiponitrile, acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, hexamethylene diisocyanate, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile.

[0242] The nitrile compound may be included in an amount of 1.0 wt% to 10 wt%, specifically 1.0 wt% to 5.0 wt%, of the total weight of the non-aqueous electrolyte. When the content of the nitrile compound satisfies the above range, a stable film is formed on the surfaces of the negative electrode and the positive electrode, thereby suppressing the generation of gas generated by the side reaction between the positive electrode and the electrolyte and effectively suppressing the dissolution of metal foreign substances.

[0243] The benzene-based compound may include fluorobenzene. The benzene-based compound may be included in an amount of 0.01 to 10 wt%, specifically 0.05 to 5.0 wt%, based on the total weight of the non-aqueous electrolyte.

[0244] The above amine compound may include triethanolamine or ethylenediamine. The above amine compound may be included in an amount of 0.01 to 10 wt%, specifically 0.05 to 5.0 wt%, based on the total weight of the non-aqueous electrolyte.

[0245] The silane compound may include tetravinylsilane. The silane compound may be included in an amount of 0.01 to 10 wt%, specifically 0.05 to 5.0 wt%, based on the total weight of the non-aqueous electrolyte.

[0246]

[0247] The lithium secondary battery may include an electrode assembly including the positive electrode, the negative electrode, and a separator interposed between the positive electrode and the negative electrode; and the electrolyte. The lithium secondary battery may include a battery case, and in this case, the electrode assembly and the electrolyte may be housed within the battery case.

[0248]

[0249] The lithium secondary battery according to the present invention as described above can be usefully used in portable devices such as mobile phones, laptop computers, and digital cameras, and electric vehicles such as hybrid electric vehicles (HEVs).

[0250] There is no particular limitation on the external shape of the lithium secondary battery of the present invention, but it may be a cylindrical shape using a can, a square shape, a pouch shape, or a coin shape.

[0251] The lithium secondary battery according to the present invention can be used not only as a battery cell used as a power source for a small device, but can also be preferably used as a unit battery in a medium- to large-sized battery module including a plurality of battery cells.

[0252]

[0253] Hereinafter, the present invention will be described in detail with examples to specifically illustrate it. However, the examples according to the present invention may be modified in various ways, and the scope of the present invention should not be construed as being limited to the examples described below. These examples are provided to more fully explain the present invention to those of average skill in the art.

[0254]

[0255] [Example]

[0256] Example 1.

[0257] (Polar electrode manufacturing)

[0258] N-methylpyrrolidone (NMP) with positive electrode active material (Li(Ni) 0.6 Mn 0.3 Co 0.1)O2), conductive agent (carbon nanotube), binder (PVDF), and thickener (CMC) were dissolved in a weight ratio of 97.0:1.20:1.44:0.36, and then a compound represented by the chemical formula 1A was added as a film-forming additive to an amount of 0.01 wt% to prepare a positive electrode slurry composition. The prepared positive electrode slurry composition was applied to a current collector made of aluminum foil (Al foil) having a thickness of 12 μm, and then dried and rolled at 50°C for 2 hours to prepare a positive electrode having a positive electrode mixture layer formed thereon.

[0259]

[0260] (Cathode manufacturing)

[0261] A cathode active material (graphite and SiC = 95:5 weight ratio), a binder (SBR), and bundled single-walled carbon nanotubes (SWCNT, length: 7 μm, specific surface area: 1,000 m) with an average diameter of 10 nm were mixed in distilled water. 2 / g, manufacturer: Nano New Materials) was added in a ratio of 96.84:3.15:0.01 parts by weight to prepare a negative electrode active material slurry. The above-prepared negative electrode active material slurry was applied to a copper current collector having a thickness of 15 ㎛, and then dried and rolled to prepare a negative electrode (see Table 1 below).

[0262]

[0263] (Manufacturing of non-aqueous electrolyte)

[0264] LiPF6 was dissolved to 1.2 M in a non-aqueous solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of 2:7:1, and then vinylene carbonate was added to 0.5 wt% to prepare a non-aqueous electrolyte.

[0265]

[0266] (Secondary battery manufacturing)

[0267] An electrode assembly was manufactured by interposing a porous separator polypropylene between the positive electrode and the negative electrode manufactured above, and then the assembly was placed in a battery case, and the non-aqueous electrolyte manufactured above was injected to manufacture a lithium secondary battery.

[0268]

[0269] Example 2.

[0270] (Polar electrode manufacturing)

[0271] N-methylpyrrolidone (NMP) with positive electrode active material (Li(Ni) 0.6 Mn 0.3 Co 0.1 )O2), conductive agent (carbon nanotube), binder (PVDF), and thickener (CMC) were dissolved in a weight ratio of 97.0:1.20:1.44:0.36, and then a compound represented by the chemical formula 1A was added as a film-forming additive to an amount of 10.0 wt% to prepare a positive electrode slurry composition. The prepared positive electrode slurry composition was applied to a current collector made of aluminum foil (Al foil) having a thickness of 12 μm, and then dried and rolled at 50°C for 2 hours to prepare a positive electrode having a positive electrode mixture layer formed thereon.

[0272]

[0273] (Secondary battery manufacturing)

[0274] A lithium secondary battery was manufactured in the same manner as in Example 1, except that the above positive electrode was used.

[0275]

[0276] Example 3.

[0277] (Polar electrode manufacturing)

[0278] N-methylpyrrolidone (NMP) with positive electrode active material (Li(Ni) 0.6 Mn 0.3 Co 0.1)O2), conductive agent (carbon nanotube), binder (PVDF), and thickener (CMC) were dissolved in a weight ratio of 97.0:1.20:1.44:0.36, and then a compound represented by the chemical formula 1A was added as a film-forming additive to an amount of 1.0 wt% to prepare a positive electrode slurry composition. The prepared positive electrode slurry composition was applied to a current collector made of aluminum foil (Al foil) having a thickness of 12 μm, and then dried and rolled at 50°C for 2 hours to prepare a positive electrode having a positive electrode mixture layer formed thereon.

[0279]

[0280] (Secondary battery manufacturing)

[0281] A lithium secondary battery was manufactured in the same manner as in Example 1, except that the above positive electrode was used.

[0282]

[0283] Example 4.

[0284] A positive electrode and a lithium secondary battery were manufactured in the same manner as in Example 3, except that when manufacturing the positive electrode slurry composition, the compound represented by the chemical formula 1B was included as a film-forming additive in the positive electrode slurry composition instead of the compound represented by the chemical formula 1A.

[0285]

[0286] Example 5.

[0287] A positive electrode and a lithium secondary battery were manufactured in the same manner as in Example 3, except that when manufacturing the positive electrode slurry composition, the compound represented by the chemical formula 1C was included as a film-forming additive in the positive electrode slurry composition instead of the compound represented by the chemical formula 1A.

[0288]

[0289] Example 6.

[0290] A positive electrode and a lithium secondary battery were manufactured in the same manner as in Example 3, except that when manufacturing the positive electrode slurry composition, the compound represented by the chemical formula 1D was included as a film-forming additive in the positive electrode slurry composition instead of the compound represented by the chemical formula 1A.

[0291]

[0292] Example 7.

[0293] A positive electrode and a lithium secondary battery were manufactured in the same manner as in Example 3, except that when manufacturing the positive electrode slurry composition, a compound represented by Chemical Formula 1E was included as a film-forming additive in the positive electrode slurry composition instead of the compound represented by Chemical Formula 1A.

[0294]

[0295] Example 8.

[0296] A positive electrode and a lithium secondary battery were manufactured in the same manner as in Example 3, except that 5.0 wt% of a compound represented by Chemical Formula 1A was included as a film-forming additive in the positive electrode slurry composition when manufacturing the positive electrode slurry composition.

[0297]

[0298] Example 9.

[0299] A positive electrode and a lithium secondary battery were manufactured in the same manner as in Example 3, except that 8.0 wt% of a compound represented by Chemical Formula 1A was included as a film-forming additive in the positive electrode slurry composition when manufacturing the positive electrode slurry composition.

[0300]

[0301] Comparative Example 1.

[0302] (Polar electrode manufacturing)

[0303] Cathode active material (Li(Ni) 0.6 Mn 0.3 Co 0.1)O2), a conductive agent (carbon black), a binder (PVDF), and a thickener (CMC) were added to N-methylpyrrolidone (NMP) at a weight ratio of 92:5:2:1 to prepare a positive electrode slurry composition. The positive electrode slurry composition thus prepared was applied to a 12 μm thick aluminum foil (Al foil) current collector, and then dried and rolled at 50°C for 2 hours to prepare a positive electrode having a positive electrode mixture layer formed thereon.

[0304]

[0305] (Secondary battery manufacturing)

[0306] A lithium secondary battery was manufactured in the same manner as in Example 1, except that the above positive electrode was used.

[0307]

[0308] Comparative Example 2.

[0309] (Manufacturing of non-aqueous electrolyte)

[0310] LiPF6 was dissolved to 1.2 M in a non-aqueous solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of 2:7:1, and then 1.0 wt% of a compound represented by the chemical formula 1A and 0.5 wt% of vinylene carbonate were added to prepare a non-aqueous electrolyte.

[0311]

[0312] (Secondary battery manufacturing)

[0313] A lithium secondary battery was manufactured in the same manner as in Comparative Example 1, except that the non-aqueous electrolyte was injected.

[0314]

[0315] Comparative Example 3.

[0316] A positive electrode and a lithium secondary battery were manufactured in the same manner as in Example 3, except that when manufacturing the positive electrode slurry composition, the compound represented by Chemical Formula 3 was included as a film-forming additive in the positive electrode slurry composition instead of the compound represented by Chemical Formula 1A.

[0317] [Chemical Formula 3]

[0318]

[0319]

[0320] Comparative Example 4.

[0321] A positive electrode and a lithium secondary battery were manufactured in the same manner as in Example 3, except that when manufacturing the positive electrode slurry composition, the compound represented by Chemical Formula 4 was included as a film-forming additive in the positive electrode slurry composition instead of the compound represented by Chemical Formula 1A.

[0322] [Chemical Formula 4]

[0323]

[0324]

[0325] Comparative Example 5.

[0326] A positive electrode and a lithium secondary battery were manufactured in the same manner as in Example 3, except that when manufacturing the positive electrode slurry composition, the compound represented by Chemical Formula 5 was included as a film-forming additive in the positive electrode slurry composition instead of the compound represented by Chemical Formula 1A.

[0327] [Chemical Formula 5]

[0328]

[0329]

[0330] Experimental example

[0331] Experimental Example 1. Evaluation of High-Temperature Cycle Characteristics

[0332] The lithium secondary batteries manufactured in Examples 1 to 9 and the lithium secondary batteries manufactured in Comparative Examples 1 to 5 were each charged to 4.5 V at room temperature (25°C) at a 0.33 C rate under constant current / constant voltage conditions, discharged for 10 seconds under a 0.33 C rate condition, and then the initial capacity was measured using a PNE-0506 charger / discharger (manufacturer: PNE solution).

[0333] Then, 400 cycles were performed, with one cycle being a high voltage charge to 4.5 V under constant current / constant voltage conditions at a 0.33 C rate at a high temperature (45°C) and a discharge to 2.5 V under constant current conditions at a 0.33 C rate, and then the capacity retention rate, resistance increase rate, and gas generation amount were measured, and the results are shown in Table 1 below.

[0334] Capacity retention rate after 400 cycles (%) Resistance increase rate (%) Gas generation (㎕) Example 184.826.85,100 Example 285.027.15,095 Example 385.826.15,040 Example 485.926.35,090 Example 585.525.85,000 Example 685.626.75,090 Example 785.826.55,075 Example 885.926.05,030 Example 985.526.65,085 Comparative example 142.564.513,800 Comparative example 252.453.312,700 Comparative example 367.447.310,300Comparative example 462.868.79,580Comparative example 568.477.59,905

[0335]

[0336] Referring to Table 1 above, it can be confirmed that in the case of the lithium secondary batteries manufactured in Examples 1 to 9 of the present invention, the capacity retention rate (%), resistance increase rate, and gas generation amount after high-temperature cycling are significantly improved compared to the lithium secondary batteries of Comparative Examples 1 to 5.

[0337]

[0338] Experimental Example 2. Evaluation of High-Temperature Storage Characteristics

[0339] The lithium secondary batteries manufactured in Examples 1 to 9 and the lithium secondary batteries manufactured in Comparative Examples 1 to 5 were each charged at high voltages up to 4.5 V under constant current / constant voltage conditions at a 0.33 C rate at room temperature (25°C), discharged for 10 seconds under a 0.33 C rate condition, and then the initial capacity was measured using a PNE-0506 charger / discharger (manufacturer: PNE solution).

[0340] Then, after storing at high temperature (60℃) for 16 weeks, one cycle of charging to 4.5 V under constant current / constant voltage conditions at 0.33 C rate and discharging to 2.5 V under constant current conditions at 0.33 C rate was performed, and then the capacity retention rate, resistance increase rate, and gas generation amount were measured, and the results are shown in Table 2 below.

[0341] Capacity retention rate (%) after high temperature (65℃) storage Resistance increase rate (%) Gas generation amount (㎕) Example 188.93 1.24,395 Example 288.83 1.04,400 Example 389.83 0.24,325 Example 489.93 0.14,355 Example 589.23 0.54,335 Example 689.93 0.94,315 Example 789.53 0.84,295 Example 889.93 0.04,300 Example 989.53 0.14,385 Comparative example 154.27 2.4 15,200 Comparative example 265.96 1.8 13,300 Comparative example 369.450.39,800Comparison Example 455.788.210,860Comparison Example 559.597.511,050

[0342]

[0343] Referring to Table 2 above, it can be confirmed that the capacity retention rate (%), resistance increase rate, and gas generation amount after high-temperature storage of the lithium secondary batteries manufactured in Examples 1 to 9 of the present invention are significantly improved compared to the lithium secondary batteries of Comparative Examples 1 to 5.

[0344]

[0345] Experimental Example 3. Hot Box Evaluation

[0346] The lithium secondary batteries manufactured in Examples 1 to 9 and the lithium secondary batteries manufactured in Comparative Examples 1 to 5 were each fully charged to 100% of SOC (State Of Charge), the fully charged battery cells were stored inside a box, and the temperature inside the box was increased from room temperature to 150°C at 2°C / min, and then stored at 150°C for 120 minutes. It was checked whether the lithium secondary batteries ignited during storage, and the results are shown in Table 3 below. In Table 3 below, if the lithium secondary batteries ignited, it was indicated as Fail, and if they did not ignite, it was indicated as Pass.

[0347] Hot box evaluation example 1Pass example 2Pass example 3Pass example 4Pass example 5Pass example 6Pass example 7Pass example 8Pass example 9Pass Comparison example 1Fail Comparison example 2Fail Comparison example 3Fail Comparison example 4Fail Comparison example 5Fail

[0348]

[0349] Referring to Table 3 above, it can be seen that the lithium secondary batteries manufactured in Examples 1 to 9 of the present invention did not ignite even when stored at high temperatures. On the other hand, it can be seen that most of the lithium secondary batteries manufactured in Comparative Examples 1 to 5 ignited when stored at high temperatures.

Claims

1. Contains a positive electrode active material, a film-forming additive and a solvent. The above film-forming additive is a compound represented by the following chemical formula 1, a positive electrode slurry composition for a lithium secondary battery: [Chemical Formula 1] In the above chemical formula 1, L1, L2 and L3 are each independently a direct bond or an alkylene group having 1 to 10 carbon atoms, R1 and R2 are each independently an alkenyl group having 2 to 7 carbon atoms or an alkynyl group having 2 to 7 carbon atoms, R3 is an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 7 carbon atoms, When both R1 and R2 are alkynyl groups having 2 to 7 carbon atoms, R3 is an alkyl group having 1 to 5 carbon atoms.

2. In paragraph 1, In the above chemical formula 1, A positive electrode slurry composition for a lithium secondary battery, wherein L1, L2, and L3 are each independently a direct bond or an alkylene group having 1 to 5 carbon atoms, R1 and R2 are each independently an alkenyl group having 2 to 5 carbon atoms or an alkynyl group having 2 to 5 carbon atoms, and R3 is an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 5 carbon atoms.

3. In paragraph 1, A positive electrode slurry composition for a lithium secondary battery, wherein in the above chemical formula 1, L1, L2 and L3 are each independently an alkylene group having 1 to 3 carbon atoms, R1 and R2 are each independently an alkenyl group having 2 to 5 carbon atoms, and R3 is an alkenyl group having 2 to 5 carbon atoms.

4. In paragraph 3, A positive electrode slurry composition for a lithium secondary battery, wherein in the above chemical formula 1, L1, L2 and L3 are each independently an alkylene group having 1 to 3 carbon atoms, R1 and R2 are each independently an alkenyl group having 2 to 4 carbon atoms, and R3 is an alkenyl group having 2 to 4 carbon atoms.

5. In paragraph 1, A positive electrode slurry composition for a lithium secondary battery, wherein in the above chemical formula 1, L1, L2 and L3 are each independently an alkylene group having 1 to 3 carbon atoms, R1 and R2 are each independently an alkynyl group having 2 to 5 carbon atoms, and R3 is an alkyl group having 1 to 3 carbon atoms.

6. In paragraph 5, A positive electrode slurry composition for a lithium secondary battery, wherein in the above chemical formula 1, L1, L2 and L3 are direct bonds or alkylene groups having 1 to 3 carbon atoms, R1 and R2 are alkynyl groups having 2 to 4 carbon atoms, and R3 is an alkyl group having 1 to 3 carbon atoms.

7. In paragraph 1, A positive electrode slurry composition for a lithium secondary battery, wherein the compound represented by the above chemical formula 1 is any one of the compounds represented by the following chemical formulas 1A to 1E: [Chemical Formula 1A] [Chemical Formula 1B] [Chemical Formula 1C] [Chemical Formula 1D] [Chemical Formula 1E] .

8. In paragraph 1, A positive electrode slurry composition for a lithium secondary battery, wherein the film-forming additive is included in an amount of 0.01 wt% to 10 wt% based on the total solid content weight of the positive electrode slurry composition.

9. In paragraph 1, A positive electrode slurry composition for a lithium secondary battery, wherein the film-forming additive is included in an amount of 0.01 wt% to 8 wt% based on the total solid content weight of the positive electrode slurry composition.

10. In paragraph 1, A positive electrode slurry composition wherein the positive electrode active material comprises a compound represented by the following chemical formula 2. [Chemical Formula 2] Li 1+a Ni x Co y M 1 z M 2 w O2 In the above chemical formula 2, M 1 is Mn, Al or a combination thereof, M 2 is at least one selected from the group consisting of Al, Zr, W, Ti, Mg, Ca and Sr, and 0≤a≤0.5, 0 <x<1.0, 0<y≤0.4, 0<z≤0.4, 0≤w≤0.1 이다.

11. In paragraph 1, A positive electrode slurry composition for a lithium secondary battery, wherein the positive electrode slurry composition for a lithium secondary battery further comprises at least one of a conductive material, a binder, and a thickener.

12. Includes a positive electrode composite layer including a positive electrode active material and a film-forming additive, The above film-forming additive is a compound represented by the following chemical formula 1: A positive electrode for a lithium secondary battery: [Chemical Formula 1] In the above chemical formula 1, L1, L2 and L3 are each independently a direct bond or an alkylene group having 1 to 10 carbon atoms, R1 and R2 are each independently an alkenyl group having 2 to 7 carbon atoms or an alkynyl group having 2 to 7 carbon atoms, R3 is an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 7 carbon atoms, When both R1 and R2 are alkynyl groups having 2 to 7 carbon atoms, R3 is an alkyl group having 1 to 5 carbon atoms.

13. In paragraph 12, The above positive electrode composite layer is an anode including a boron (B)-containing film.

14. A step of applying a positive electrode slurry composition on a positive electrode current collector; and A step of forming a positive electrode mixture layer by drying and then rolling the positive electrode slurry composition; A method for manufacturing a positive electrode for a secondary battery, wherein the positive electrode slurry composition is the positive electrode slurry composition of claim 1.

15. A lithium secondary battery comprising a positive electrode according to Article 12, a negative electrode opposite to the positive electrode, a separator, and an electrolyte.

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