Positive electrode slurry composition for rechargeable lithium battery, positive electrode, and rechargeable lithium battery manufacturing using the same

Abstract

Provided are a positive electrode slurry composition for a rechargeable lithium battery, a positive electrode manufactured using the positive electrode slurry composition, and a rechargeable lithium battery. A positive electrode slurry composition for a rechargeable lithium battery includes two types of hydrogenated nitrile rubber derivatives having different weight-average molecular weights, a conductive material, a positive electrode active material, and a dispersion medium.

Description

Technical Field

[0001] A positive electrode slurry composition for a rechargeable lithium battery, a positive electrode manufactured using the positive electrode slurry composition, and a rechargeable lithium battery are disclosed. Background Technology

[0002] Rechargeable lithium-ion batteries can be recharged, and their energy density per unit weight is three times or more that of conventional lead-acid batteries (such as nickel-cadmium, nickel-metal hydride, and nickel-zinc batteries). Rechargeable lithium-ion batteries can also be charged at high rates and are commercially manufactured for laptops, cell phones, power tools, electric bicycles, and more. Therefore, improving the energy density of rechargeable lithium-ion batteries can be advantageous.

[0003] A rechargeable lithium battery is manufactured by injecting an electrolyte into an electrode assembly, which includes a positive electrode and a negative electrode. The positive electrode includes a positive electrode active material capable of inserting / deintercalating lithium ions, and the negative electrode includes a negative electrode active material capable of inserting / deintercalating lithium ions.

[0004] Typically, in positive electrode slurry compositions used to manufacture positive electrodes, hydrogenated nitrile rubber is used as a dispersant for dispersing conductive materials, and polyvinylidene fluoride is used as a binder.

[0005] However, when using high-nickel (high-Ni) positive electrode active materials with a large amount of residual lithium in the form of LiOH, Li2CO3, etc., the following problems may occur: HF is generated due to the reaction between the corresponding residual lithium and polyvinylidene fluoride, which modifies polyvinylidene fluoride, changes the viscosity of the positive electrode slurry composition, causes it to gel, and deteriorates the processability of the coating. Summary of the Invention

[0006] Some example embodiments include a positive electrode slurry composition for a rechargeable lithium battery that reduces or suppresses viscosity changes in the positive electrode slurry composition while maintaining the dispersibility of the conductive material.

[0007] Some example embodiments include a positive electrode slurry composition for a rechargeable lithium battery, the positive electrode slurry composition comprising two types of hydrogenated nitrile rubber derivatives with different weight-average molecular weights, a conductive material, a positive electrode active material, and a dispersion medium.

[0008] Some example embodiments include a positive electrode for a rechargeable lithium battery manufactured using a positive electrode slurry composition according to the foregoing example embodiments.

[0009] Some example embodiments include a rechargeable lithium battery that includes a positive electrode according to the foregoing example embodiments.

[0010] The positive electrode slurry composition for rechargeable lithium batteries, comprising two types of hydrogenated nitrile butadiene rubber derivatives as described above, can reduce or suppress viscosity changes in the positive electrode slurry composition and improve coating processability.

[0011] Therefore, positive electrodes and rechargeable lithium batteries manufactured using the positive electrode slurry composition for rechargeable lithium batteries according to the foregoing example embodiments can exhibit desired or improved cycle life characteristics. Attached Figure Description

[0012] Figures 1 to 4 This is a schematic diagram illustrating a rechargeable lithium battery according to some example embodiments. Detailed Implementation

[0013] Hereinafter, exemplary embodiments of the present disclosure are described in detail. However, these embodiments are exemplary, and the invention is not limited thereto; rather, the invention is defined by the scope of the claims.

[0014] As used herein, unless otherwise specifically defined, it is understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, the element may be directly on the other element, or there may be an intervening element between them.

[0015] As used herein, the singular may also include the plural unless otherwise specifically defined. Furthermore, unless otherwise stated, “A or B” may mean “including A, including B, or including both A and B”.

[0016] As used herein, “combination of” can mean a mixture, stack, compound, copolymer, alloy, blend or reaction product of the components.

[0017] As used herein, unless otherwise defined, particle size can be the average particle size. Furthermore, particle size can refer to the average particle size (D50), which represents the diameter of particles that constitute 50% of the total volume in a particle size distribution. The average particle size (D50) can be measured by methods known to those skilled in the art (e.g., by a particle size analyzer, or by transmission electron microscopy or scanning electron microscopy images). Optionally, data analysis can be performed using a dynamic light scattering measurement device, and the number of particles in each particle size range can be counted. Thus, the average particle size (D50) value can be readily obtained by calculation. Optionally, laser diffraction can be used to measure the average particle size. When measured by laser diffraction, for example, the particles to be measured are dispersed in a dispersion medium and then introduced into a commercially available laser diffraction particle size measurement device (e.g., Microtrac MT 3000) and irradiated with ultrasound at approximately 28 kHz at a 60 W output to calculate the average particle size (D50) based on 50% of the particle size distribution in the measurement device.

[0018] In this specification, the weight-average molecular weight (Mw) of the binder may be a value measured using, for example, gel permeation chromatography (GPC).

[0019] When the terms “about” or “substantially” are used in conjunction with numerical values ​​in this specification, it is intended that the relevant numerical values ​​include a tolerance of ±10% around the stated value. When a range is specified, the range includes all values ​​within that range, such as increments of 0.1%.

[0020] Positive electrode slurry composition for rechargeable lithium batteries: Some example embodiments include positive electrode slurry compositions for rechargeable lithium batteries, the positive electrode slurry compositions comprising two types of hydrogenated nitrile butadiene rubber derivatives with different weight-average molecular weights, conductive materials, positive electrode active materials, and dispersion media.

[0021] Of the two types of hydrogenated nitrile butadiene rubber derivatives, those with relatively small weight-average molecular weights can serve as dispersants for conductive materials, while those with relatively large weight-average molecular weights can serve as binders and replace polyvinylidene fluoride.

[0022] Therefore, positive electrode slurry compositions for rechargeable lithium batteries comprising two types of hydrogenated nitrile butadiene rubber derivatives can reduce or suppress viscosity changes in the positive electrode slurry composition and improve coating processability.

[0023] The following describes in detail the positive electrode slurry composition for a rechargeable lithium battery according to the foregoing example embodiments.

[0024] Hydrogenated nitrile rubber derivatives The two types of hydrogenated nitrile butadiene rubber derivatives may include: a first hydrogenated nitrile butadiene rubber derivative having a weight-average molecular weight in the range of about 100,000 g / mol to about 400,000 g / mol or about 100,000 g / mol to about 200,000 g / mol; and a second hydrogenated nitrile butadiene rubber derivative having a weight-average molecular weight in the range of about 250,000 g / mol to about 1,000,000 g / mol.

[0025] When the weight-average molecular weight of the first hydrogenated nitrile butadiene rubber derivative is less than the lower limit of the above range, the first hydrogenated nitrile butadiene rubber derivative is not suitable for dispersing conductive materials, and even when preparing and storing the conductive material dispersion, the conductive material may agglomerate, resulting in poor viscosity and particle size stability.

[0026] Meanwhile, when the weight-average molecular weight of the second hydrogenated nitrile butadiene rubber derivative is less than the lower limit, the second hydrogenated nitrile butadiene rubber derivative is not suitable for dispersion in the slurry composition, which may affect the increase of positive electrode resistance and the decrease of adhesive strength.

[0027] The weight ratio of the first hydrogenated nitrile butadiene rubber derivative to the second hydrogenated nitrile butadiene rubber derivative may be in the range of about 1:1 to about 1:20, about 1:3 to about 1:15, or about 1:5 to about 1:12.

[0028] Within this range, a synergistic effect can be achieved by using a combination of first hydrogenated nitrile butadiene rubber derivatives and second hydrogenated nitrile butadiene rubber derivatives.

[0029] Based on a total positive electrode slurry composition of 100 wt%, the first hydrogenated nitrile butadiene rubber derivative may be included in an amount ranging from about 0.01 wt% to about 0.5 wt%, about 0.05 wt% to about 0.3 wt%, or about 0.05 wt% to about 0.1 wt%; and the second hydrogenated nitrile butadiene rubber derivative may be included in an amount ranging from about 0.1 wt% to about 5 wt%, about 0.5 wt% to about 3 wt%, or about 1 wt% to about 1.5 wt%.

[0030] Within this range, a synergistic effect can be achieved by using a combination of first hydrogenated nitrile butadiene rubber derivatives and second hydrogenated nitrile butadiene rubber derivatives.

[0031] The first and second hydrogenated nitrile butadiene rubber derivatives may each independently comprise: a first structural unit derived from acrylonitrile, represented by chemical formula 1; a second structural unit comprising a structural unit derived from hydrogenated butadiene, represented by chemical formula 2A, and a structural unit derived from butadiene, represented by chemical formula 2B; a third structural unit, represented by chemical formula 3; and a fourth structural unit, represented by chemical formula 4. Chemical Formula 1: .

[0032] Chemical formula 2A: .

[0033] Chemical formula 2B: .

[0034] Chemical formula 3: .

[0035] Chemical formula 4: .

[0036] In chemical formula 3, R 1 It includes or comprises hydrogen, substituted or unsubstituted C1-C20 alkyl, ester (-COOR, where R is a substituted or unsubstituted C1-C20 alkyl), cyano (-CN), pyrrolidone (-C3H5NHCO), carboxyl (-COOH), caprolactam (-NCOC5H) 10 ), morpholino (-NC4H8O), hydroxyl (-OH), amino (-NH2), vinyl (-CH=CH2), epoxy (-COCH2) or thiol (-SH).

[0037] Compared to the hydrogenated nitrile butadiene rubber itself, the first hydrogenated nitrile butadiene rubber derivative and the second hydrogenated nitrile butadiene rubber derivative each independently include a repeating unit represented by chemical formula 3, wherein the carboxyl group (-COOH) of chemical formula 3 is a functional group that helps to improve adhesive strength.

[0038] Therefore, the first hydrogenated nitrile butadiene rubber derivative and the second hydrogenated nitrile butadiene rubber derivative can each independently have a higher adhesive strength than the hydrogenated nitrile butadiene rubber itself.

[0039] For example, based on 100 wt% of a hydrogenated nitrile butadiene rubber derivative, the first and second hydrogenated nitrile butadiene rubber derivatives may each independently include the first structural unit in an amount ranging from about 20 wt% to about 40 wt%, for example, from about 25 wt% to about 40 wt%, from about 30 wt% to about 40 wt%, or from about 30 wt% to about 35 wt%. Based on the hydrogenated nitrile butadiene rubber derivative, including the first structural unit in an amount less than about 20 wt% may degrade electrolyte resistance, and including the first structural unit in an amount greater than about 40 wt% may degrade the mechanical properties of the positive electrode, such as flexibility.

[0040] For example, based on 100 wt% of a hydrogenated nitrile butadiene rubber derivative, the first and second hydrogenated nitrile butadiene rubber derivatives may each independently include the second structural unit in an amount ranging from about 30 wt% to about 78 wt%, for example, from about 30 wt% to about 70 wt%, from about 40 wt% to about 70 wt%, from about 50 wt% to about 70 wt%, or from about 50 wt% to about 60 wt%. When the second structural unit is included in the above-mentioned range based on 100 wt% of the aforementioned hydrogenated nitrile butadiene rubber derivative, a conductive material such as CNT can be dispersed within the electrode plate as needed.

[0041] For example, based on 100 wt% of hydrogenated nitrile butadiene rubber derivatives, the first and second hydrogenated nitrile butadiene rubber derivatives may each independently include a third structural unit in an amount ranging from about 2 wt% to about 10 wt%, for example, from about 3 wt% to about 10 wt%, from about 4 wt% to about 10 wt%, or from about 4 wt% to about 8 wt%. Based on 100 wt% of hydrogenated nitrile butadiene rubber derivatives, including the third structural unit in an amount less than about 2 wt% may reduce the adhesive strength of the binder, while including the third structural unit in an amount greater than about 10 wt% may excessively increase the adhesive strength of the binder, leading to a reduction in the flexibility of the electrode plate.

[0042] For example, based on 100 wt% of a hydrogenated nitrile butadiene rubber derivative, the first and second hydrogenated nitrile butadiene rubber derivatives may each independently include a fourth structural unit in an amount ranging from about 0 wt% to about 20 wt%, for example, from about 1 wt% to about 15 wt%, from about 5 wt% to about 20 wt%, from about 5 wt% to about 15 wt%, or from about 5 wt% to about 10 wt%. Based on 100 wt% of the aforementioned hydrogenated nitrile butadiene rubber derivative, when the fourth structural unit is not included, the flexibility of the electrode plate may be reduced, and the dispersion of conductive materials such as CNTs within the electrode plate may be reduced; and when the fourth structural unit is included in an amount greater than about 20 wt%, the adhesive strength of the binder may be reduced.

[0043] In some example embodiments, the first hydrogenated nitrile butadiene rubber derivative and the second hydrogenated nitrile butadiene rubber derivative each independently comprise, based on 100 wt%, a second structural unit comprising greater than or equal to about 90 wt% and less than about 100 wt% of a hydrogenated butadiene-derived structural unit represented by chemical formula 2A; and based on 100 wt%, a second structural unit comprising greater than about 0 wt% and less than or equal to about 10 wt% of a butadiene-derived structural unit represented by chemical formula 2B.

[0044] When the butadiene-derived structural unit represented by Formula 2B is not included in the second structural unit (0 wt%), the π-π bonding between the conductive material (CNT) and butadiene may be difficult, resulting in poor CNT dispersion within the electrode plate. When the butadiene-derived structural unit represented by Formula 2B is included in an amount greater than about 10 wt%, the solubility of the binder in the solvent (e.g., NMP) within the positive electrode slurry composition may be poor, resulting in poor CNT wetting.

[0045] The first and second hydrogenated nitrile butadiene rubber derivatives can each be represented independently by chemical formula A. For example, chemical formula A is a copolymer comprising structural units of chemical formula 1, chemical formula 2A, chemical formula 2B, chemical formula 3, and chemical formula 4, but for the sake of simplicity, chemical formula A does not list each individual repeating unit.

[0046] Chemical formula A: .

[0047] In chemical formula A, R 1 and R 2 The definition is as described above. For example, R 1 It may be or include methyl, R 2 It may include or contain a carboxyl group (-COOH).

[0048] In addition, in chemical formula A, "a" to "d" can each be an integer from 1 to 20 independently.

[0049] conductive materials Conductive materials are included to provide electrode conductivity, and any electrically conductive material can be used as a conductive material unless the conductive material causes a chemical change in the battery. Examples of conductive materials may include: carbon-based materials, such as at least one of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.; metallic materials, including metal powders or metal fibers of at least one of copper, nickel, aluminum, silver, etc.; conductive polymers, such as polyphenylene derivatives; or mixtures thereof.

[0050] For example, carbon nanotubes can be used as conductive materials, and in this case, conductive material dispersions can be prepared in the presence of hydrogenated nitrile rubber derivatives and applied to positive electrode slurries to improve the conductivity of the positive electrode.

[0051] The weight ratio of the first hydrogenated nitrile rubber derivative to the conductive material can be in the range of about 1:1 to about 1:10 or about 1:3 to about 1:7.

[0052] Within this range, the dispersibility of conductive materials can be improved by using first hydrogenated nitrile rubber derivatives.

[0053] Furthermore, the positive electrode slurry composition, based on a total amount of 100 wt%, includes conductive material in an amount equal to or greater than about 0 wt% and less than or equal to about 5 wt%. When the amount of conductive material exceeds the upper limit of the above range, the conductive material may not be well dispersed in the first hydrogenated nitrile rubber derivative, which serves as a dispersant, and the conductive material may agglomerate even during the preparation and storage of the conductive material dispersion, resulting in poor viscosity and particle size stability.

[0054] Positive electrode active material The positive electrode active material can be or includes compounds capable of intercalating and deintercalating lithium (lithium intercalation compounds). For example, a composite oxide of lithium with one or more types of metals such as or including at least one of cobalt, manganese, nickel, and combinations thereof can be used.

[0055] The composite oxide can be or includes lithium transition metal composite oxides, and examples of such composite oxides can include at least one of lithium nickel oxides, lithium cobalt oxides, lithium manganese oxides, lithium iron phosphate compounds, cobalt-free lithium nickel manganese oxides, and combinations thereof.

[0056] As an example, a compound represented by any of the following chemical formulas can 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 Ge 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); and Li a FePO4 (0.90≤a≤1.8).

[0057] In the above chemical formulas, A is or includes at least one of Ni, Co, Mn, and combinations thereof; X is or includes at least one of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, and combinations thereof; D is or includes at least one of O, F, S, P, and combinations thereof; G is or includes at least one of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, and combinations thereof; and L 1 It is or includes at least one of Mn, Al and combinations thereof.

[0058] The positive electrode active material may be or include at least one of the following materials: lithium nickel oxide represented by chemical formula 11, lithium cobalt oxide represented by chemical formula 12, lithium iron phosphate compound represented by chemical formula 13, cobalt-free lithium nickel manganese oxide represented by chemical formula 14, and combinations thereof.

[0059] Chemical Formula 11: Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1 .

[0060] In chemical formula 11, 0.9 ≤ a1 ≤ 1.8, 0.3 ≤ x1 ≤ 1, 0 ≤ y1 ≤ 0.7, 0 ≤ z1 ≤ 0.7, 0.9 ≤ x1 + y1 + z1 ≤ 1.1 and 0 ≤ b1 ≤ 0.1, M 1 and M 2 Each is independently one or more of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is one or more of F, P, and S.

[0061] In chemical formula 11, 0.6≤x1≤1, 0≤y1≤0.4 and 0≤z1≤0.4, or 0.8≤x1≤1, 0≤y1≤0.2 and 0≤z1≤0.2.

[0062] Chemical formula 12: Li a2 Co x2 M 3 y2 O 2-b2 X b2 .

[0063] In chemical formula 12, 0.9 ≤ a² ≤ 1.8, 0.7 ≤ x² ≤ 1, 0 ≤ y² ≤ 0.3, 0.9 ≤ x² + y² ≤ 1.1 and 0 ≤ b² ≤ 0.1, M 3 X is or includes one or more of Al, B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn, and Zr, and X is or includes one or more of F, P, and S.

[0064] Chemical formula 13: Li a3 Fe x3 M 4 y3 PO 4-b3 X b3 .

[0065] In chemical formula 13, 0.9 ≤ a³ ≤ 1.8, 0.6 ≤ x³ ≤ 1, 0 ≤ y³ ≤ 0.4 and 0 ≤ b³ ≤ 0.1, M 4 X is or includes one or more of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn, and Zr, and X is or includes one or more of F, P, and S.

[0066] Chemical formula 14: Li a4 Ni x4Mn y4 M 5 z4 O 2-b4 X b4 。

[0067] In Chemical Formula 14, 0.9 ≤ a4 ≤ 1.8, 0.8 ≤ x4 < 1, 0 < y4 ≤ 0.2, 0 ≤ z4 ≤ 0.2, 0.9 ≤ x4 + y4 + z4 ≤ 1.1 and 0 ≤ b4 ≤ 0.1, M 5 is or includes at least one element such as or including at least one of Al, B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is or includes one or more of F, P, and S.

[0068] For example, the positive electrode active material may be or include a high-nickel positive electrode active material. Based on 100 mol% of the metals other than lithium in the lithium transition metal composite oxide, the nickel content of the high-nickel positive electrode active material is greater than or equal to about 80 mol%, greater than or equal to about 85 mol%, greater than or equal to about 90 mol%, greater than or equal to about 91%, or greater than or equal to about 94 mol% and less than or equal to about 99 mol%. The high-nickel positive electrode active material can achieve high capacity and can be applied to high-capacity and high-density rechargeable lithium batteries.

[0069] In addition, based on the total amount of the positive electrode paste composition of 100 wt%, the positive electrode active material is included in an amount equal to or greater than about 90 wt% to about 99.5 wt%.

[0070] Dispersion medium The dispersion medium may be or include NMP (N-methyl-2-pyrrolidone).

[0071] Properties of the composition The positive electrode paste composition may have a T.I (thixotropic index) in the range of about 0.2 to about 0.7 at 25 °C.

[0072] Within this range, it is beneficial for the paste discharge and leveling in the positive electrode coater, which is beneficial for the coating process.

[0073] Positive electrode and rechargeable lithium battery: Some exemplary embodiments include a positive electrode for a rechargeable lithium battery. The positive electrode for a rechargeable lithium battery includes a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector. The positive electrode active material layer includes two types of hydrogenated nitrile rubber derivatives, a conductive material, and a positive electrode active material.

[0074] Some example embodiments include a rechargeable lithium battery, which includes a positive electrode, a negative electrode, a separator between the positive and negative electrodes, and an electrolyte as described in the foregoing example embodiments.

[0075] These can be manufactured using the positive electrode slurry composition for rechargeable lithium batteries according to the foregoing example embodiments.

[0076] For example, when the positive electrode current collector is coated with the positive electrode slurry composition for rechargeable lithium batteries according to the above example embodiments, the solvent is removed, and a positive electrode active material layer comprising two types of hydrogenated nitrile rubber derivatives, conductive materials, and positive electrode active materials can be formed.

[0077] Electrodes and rechargeable lithium batteries manufactured using the positive electrode slurry composition for rechargeable lithium batteries according to the above example embodiments can exhibit desired or improved cycle life characteristics.

[0078] Therefore, in the positive electrode of the rechargeable lithium battery according to the above example embodiments, the same description can be applied except for the "solvent" in the above example embodiments.

[0079] In the following, a detailed description of the positive electrode for a rechargeable lithium battery and the rechargeable lithium battery according to the foregoing example embodiments is provided, excluding any descriptions that are repeated above.

[0080] positive electrode The positive electrode for a rechargeable lithium battery may include a current collector and a layer of positive electrode active material on the current collector. The positive electrode can be manufactured using a positive electrode slurry composition for a rechargeable lithium battery according to the foregoing example embodiments.

[0081] The positive electrode active material layer may include the positive electrode active material, and may also include a binder and / or a conductive material.

[0082] For example, the positive electrode may also include additives that can form a sacrificial positive electrode.

[0083] Based on a 100wt% positive electrode active material layer, the amount of positive electrode active material can be in the range of about 90wt% to about 99.5wt%, and based on a 100wt% positive electrode active material layer, the amounts of binder and conductive material can both be in the range of about 0.2wt% to about 5wt%.

[0084] The binder improves the adhesion between the positive electrode active material particles and the adhesion between the positive electrode active material particles and the current collector. Examples of binders may include at least one of the following: polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylate resin, polyester resin, and nylon, but are not limited thereto. In this disclosure, a second hydrogenated nitrile rubber derivative constitutes the binder.

[0085] Conductive materials are included to provide electrode conductivity, and any electrically conductive material can be used as a conductive material unless it causes a chemical change. Examples of conductive materials may include: carbon-based materials, such as at least one of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.; metallic materials, including metal powders or metal fibers of at least one of copper, nickel, aluminum, silver, etc.; conductive polymers, such as polyphenylene derivatives; or mixtures thereof.

[0086] Negative electrode active material The negative electrode active material may include at least one of the following: materials capable of reversibly inserting / deintercalating lithium ions, lithium metal, lithium metal alloys, materials capable of doping / dedoping lithium, and transition metal oxides.

[0087] Materials that can reversibly insert / deintercalate lithium ions can include, for example, crystalline carbon, amorphous carbon, or combinations thereof as carbon-based negative electrode active materials. Crystalline carbon can be irregular, sheet-like, flake-like, spherical, or fibrous natural or artificial graphite. Amorphous carbon can be or includes at least one of soft carbon, hard carbon, mesophase pitch carbonization products, calcined coke, etc.

[0088] Lithium metal alloys include alloys of lithium with a metal such as or including at least one of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al and Sn.

[0089] Materials capable of doping / dedoping lithium can be, or include, Si-based or Sn-based negative electrode active materials. Si-based negative electrode active materials can include silicon, silicon-carbon composites, and SiO₂. x(0 < x ≤ 2), at least one of a Si-Q alloy (where Q is an element such as or including at least one of an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element (excluding Si), a Group 15 element, a Group 16 element, a transition metal, a rare earth element, and combinations thereof), and combinations thereof. The Sn-based negative electrode active material can be or include at least one of Sn, SnO2, Sn-based alloys, and combinations thereof.

[0090] The silicon-carbon composite can be or include a composite of silicon and amorphous carbon. According to some exemplary embodiments, the silicon-carbon composite can be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, the silicon-carbon composite can include secondary particles (cores) in which primary silicon particles are assembled and an amorphous carbon coating layer (shells) located on the surface of the secondary particles. Amorphous carbon can also be present between the primary silicon particles. For example, the primary silicon particles can be coated with amorphous carbon. The secondary particles can be dispersed in an amorphous carbon matrix.

[0091] The silicon-carbon composite can also include crystalline carbon. For example, the silicon-carbon composite can include a core containing crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

[0092] The Si-based negative electrode active material or the Sn-based negative electrode active material can be mixed with a carbon-based negative electrode active material.

[0093] negative electrode The negative electrode for a rechargeable lithium battery includes a current collector and a negative electrode active material layer on the current collector. The negative electrode active material layer includes a negative electrode active material and can also include a binder and / or a conductive material.

[0094] For example, the negative electrode active material layer can include from about 90 wt% to about 99 wt% of the negative electrode active material, from about 0.5 wt% to about 5 wt% of the binder, and from about 0.5 wt% to about 5 wt% of the conductive material.

[0095] The binder attaches the negative electrode active material particles to each other and attaches the negative electrode active material to the current collector. The binder can be or include a non-aqueous binder, an aqueous binder, a dry binder, or combinations thereof.

[0096] The non-aqueous binder can include at least one of polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, and combinations thereof.

[0097] Waterborne adhesives may include at least one of styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepoxychloropropane, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0098] When using an aqueous binder as the negative electrode binder, it may further include a cellulose-based compound capable of imparting viscosity. As a cellulose-based compound, one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and their alkali metal salts may be mixed and used. The alkali metal may be or include at least one of Na, K, and Li.

[0099] Dry adhesives are polymeric materials capable of being fibrous, and may be or include at least one of, for example, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, and combinations thereof.

[0100] Conductive materials are included to provide electrode conductivity, and any electrically conductive material can be used as a conductive material unless it causes a chemical change. Examples of conductive materials include: carbon-based materials, such as at least one of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.; metallic materials, including metal powders or metal fibers of at least one of copper, nickel, aluminum, silver, etc.; conductive polymers, such as polyphenylene derivatives; or mixtures thereof.

[0101] The negative electrode current collector may include at least one of copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, polymer substrate coated with conductive metal, and combinations thereof.

[0102] Electrolyte solution Electrolyte solutions used in rechargeable lithium batteries include non-aqueous organic solvents and lithium salts.

[0103] Non-aqueous organic solvents constitute the medium for transporting ions that participate in the electrochemical reactions of the battery.

[0104] Non-aqueous organic solvents may be or include carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents, aprotic solvents, or combinations thereof.

[0105] Carbonate solvents may include at least one of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), and butyl carbonate (BC). Ester solvents may include at least one of methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanolactone, mevalonolactone, valproic acid lactone, caprolactone, etc. Ether solvents may include at least one of dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, etc. Furthermore, ketone solvents may include cyclohexanone, etc. Alcohol solvents may include ethanol, isopropanol, etc. Aprotic solvents may include at least one of the following: nitriles, such as R-CN (wherein R is a C2 to C20 straight-chain, branched or cyclic hydrocarbon group, and includes double bonds, aromatic rings or ether groups, etc.); amides, such as dimethylformamide; dioxolane, such as 1,3-dioxolane, 1,4-dioxolane, etc.; sulfolane; etc.

[0106] Non-aqueous organic solvents can be used alone or in mixtures of two or more solvents.

[0107] Furthermore, when using carbonate solvents, cyclic carbonates and chain carbonates can be mixed, and the cyclic carbonates and chain carbonates can be mixed in a volume ratio ranging from about 1:1 to about 1:9.

[0108] The electrolyte solution may also include at least one of vinyl ethyl carbonate, vinylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, and combinations thereof as additives.

[0109] Lithium salts dissolved in organic solvents supply lithium ions in batteries, enabling rechargeable lithium batteries to operate and improving lithium ion transport between the positive and negative electrodes. Examples of lithium salts can 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+1At least one of the following: (SO2) (where 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).

[0110] diaphragm Depending on the type of rechargeable lithium battery, a separator may be present between the positive and negative electrodes. The separator may include at least one of polyethylene, polypropylene, polyvinylidene fluoride, and multilayer films of two or more layers, and may include mixed multilayer films, such as polyethylene / polypropylene bilayer separators, polyethylene / polypropylene / polypropylene trilayer separators, polypropylene / polypropylene / polypropylene trilayer separators, etc.

[0111] The membrane may include a porous substrate and a coating layer on one or both surfaces of the porous substrate, comprising organic materials, inorganic materials or combinations thereof.

[0112] The porous substrate can be a polymer membrane formed from or comprising any polymer or copolymers or mixtures of two or more of the polymers, such as or including at least one of polyolefins (such as polyethylene and polypropylene), polyesters (such as polyethylene terephthalate and polybutylene terephthalate), polyacetal, polyamide, polyimide, polycarbonate, polyetherketone, polyaryletherketone, polyetherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene ether, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fiber, Teflon, and polytetrafluoroethylene.

[0113] Organic materials may include polyvinylidene fluoride polymers or (meth)acrylic acid polymers.

[0114] Inorganic materials may include inorganic particles, such as or including at least one of Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite and combinations thereof, but are not limited thereto.

[0115] Organic and inorganic materials can be mixed in a coating layer, or a coating layer containing organic materials and a coating layer containing inorganic materials can be stacked together.

[0116] Rechargeable lithium batteries Based on their shape, rechargeable lithium batteries can be classified into cylindrical batteries, prismatic batteries, pouch batteries, or coin-shaped batteries, etc. Figures 1 to 4This is a schematic diagram illustrating a rechargeable lithium battery according to some example embodiments, wherein, Figure 1 It is a cylindrical battery. Figure 2 It is a prismatic battery. Figure 3 and Figure 4 It's a pouch battery. (See reference) Figures 1 to 4 The rechargeable lithium battery 100 includes an electrode assembly 40 and a housing 50. The electrode assembly 40 has a separator 30 disposed between a positive electrode 10 and a negative electrode 20. The electrode assembly 40 is housed within the housing 50. The positive electrode 10, the negative electrode 20, and the separator 30 may be impregnated with an electrolyte solution (not shown). Figure 1 As shown, the rechargeable lithium battery 100 may include a sealing member 60 of the sealed housing 50. Additionally, in Figure 2 In this context, the rechargeable lithium battery 100 may include a positive electrode lead connector 11, a positive electrode terminal 12 connected to the positive electrode lead connector 11, a negative electrode lead connector 21, and a negative electrode terminal 22 connected to the negative electrode lead connector 21. For example... Figure 3 and Figure 4 As shown, the rechargeable lithium battery 100 includes Figure 4 The electrode connector 70 shown in the figure, or Figure 3 The positive electrode terminal 71 and negative electrode terminal 72 shown in the figure form an electrical path for inducing current formed in the electrode assembly 40 to the outside of the battery 100.

[0117] The rechargeable lithium battery according to some example embodiments can be used in, for example, automobiles, mobile phones and / or various types of electrical devices, but this disclosure is not limited thereto.

[0118] Examples and comparative examples of this disclosure are described below. However, the following examples are merely examples of this disclosure, and this disclosure is not limited to these examples.

[0119] Example 1 (1) Preparation of conductive material composition A conductive material composition is prepared by mixing carbon nanotubes (CNTs) as a conductive material, a hydrogenated nitrile butadiene rubber derivative (represented by chemical formula A and having a weight-average molecular weight of 100,000 g / mol according to the GPC method, which can be prepared by conventional polymerization methods known in the art) as a dispersant, and NMP as a solvent.

[0120] Based on a conductive material composition of 100 wt%, comprising 3 wt% carbon nanotubes and 0.60 wt% hydrogenated nitrile butadiene rubber derivative.

[0121] (2) Preparation of positive electrode slurry composition Adding LiNi as a positive electrode active material to a conductive material composition 0.91 Co 0.05 Al 0.04 A positive electrode slurry composition is prepared by using O2, a binder (which can be prepared by conventional polymerization methods known in the art) represented by chemical formula A and having a weight-average molecular weight of 250,000 g / mol according to the GPC method, and NMP as a solvent.

[0122] The positive electrode slurry composition, based on a total amount of 100 wt%, comprises 98.45 wt% positive electrode active material, 0.45 wt% carbon nanotubes, 0.09 wt% dispersant represented by chemical formula A and having a weight-average molecular weight of 100,000 g / mol according to the GPC method, and 1.01 wt% binder represented by chemical formula A and having a weight-average molecular weight of 250,000 g / mol.

[0123] (3) Manufacturing of the positive electrode The positive electrode slurry composition was coated onto a 12 μm thick Al foil, then dried and pressed at 100 °C to form a positive electrode active material layer.

[0124] (4) Manufacturing of the negative electrode Artificial graphite and silicon particles were mixed in a weight ratio of 93.5:6.5 to prepare a negative electrode active material, and the negative electrode active material, styrene-butadiene rubber binder, and carboxymethyl cellulose were mixed in a weight ratio of 97:1:2 and then dispersed in distilled water to prepare a negative electrode slurry composition.

[0125] The negative electrode slurry composition was coated onto an 8 μm thick Cu foil, then dried and pressed at 100 °C to form a negative electrode active material layer.

[0126] (5) Preparation of electrolyte solution An electrolyte solution was prepared by mixing 1.5M lithium salt (LiPF6) with a carbonate solvent comprising ethylene carbonate (EC): ethyl methyl carbonate (EMC): dimethyl carbonate (DMC) in a volume ratio of 20:40:40.

[0127] (6) Manufacturing of rechargeable lithium battery cells The manufactured positive and negative electrodes are assembled to obtain an electrode assembly, which is then inserted into a prismatic housing and an electrolyte solution is injected into it to manufacture a rechargeable lithium battery cell.

[0128] Example 2 The positive electrode slurry composition, positive electrode, and rechargeable lithium battery cell of Example 2 were manufactured in the same manner as in Example 1, except that a hydrogenated nitrile butadiene rubber derivative represented by chemical formula A and having a weight-average molecular weight of 400,000 g / mol according to the GPC method was used in the preparation of the conductive material composition.

[0129] Example 3 The positive electrode slurry composition, positive electrode, and rechargeable lithium battery cell of Example 3 were manufactured in the same manner as in Example 1, except that: when preparing the conductive material composition, a hydrogenated nitrile butadiene rubber derivative represented by chemical formula A and having a weight-average molecular weight of 250,000 g / mol according to the GPC method was used, and when preparing the positive electrode slurry composition, a hydrogenated nitrile butadiene rubber derivative represented by chemical formula A and having a weight-average molecular weight of 400,000 g / mol according to the GPC method was used.

[0130] Example 4 The positive electrode slurry composition, positive electrode, and rechargeable lithium battery cell of Example 4 were manufactured in the same manner as in Example 1, except that: when preparing the conductive material composition, a hydrogenated nitrile butadiene rubber derivative represented by chemical formula A and having a weight-average molecular weight of 250,000 g / mol according to the GPC method was used, and when preparing the positive electrode slurry composition, a hydrogenated nitrile butadiene rubber derivative represented by chemical formula A and having a weight-average molecular weight of 1,000,000 g / mol according to the GPC method was used.

[0131] Compare with Example 1 (Ref.) LiNi was used as the active material for the positive electrode. 0.91 Co 0.05 Al 0.04 A positive electrode slurry composition is prepared by adding O2, carbon nanotubes as a conductive material, and polyvinylidene fluoride as a binder, and adding NMP as a solvent.

[0132] Based on a total positive electrode slurry composition of 100 wt%, comprising 98.45 wt% positive electrode active material, 0.45 wt% carbon nanotubes and 1.1 wt% polyvinylidene fluoride.

[0133] Comparison Example 2 LiNi was used as the active material for the positive electrode. 0.91 Co 0.05 Al 0.04 A positive electrode slurry composition is prepared by adding O2, carbon nanotubes as conductive materials, hydrogenated nitrile rubber derivatives as binders, and NMP as a solvent.

[0134] The positive electrode slurry composition, based on a total of 100 wt%, comprises 98.45 wt% positive electrode active material, 0.45 wt% carbon nanotubes, and 1.1 wt% hydrogenated nitrile butadiene rubber derivative represented by chemical formula A and having a weight-average molecular weight of 250,000 g / mol according to the GPC method.

[0135] Evaluation Example 1: Evaluation of Positive Electrode Slurry Composition The positive electrode slurry compositions according to Examples 1 to 4 and Comparative Examples 1 and 2 were evaluated using the following methods, and the results are shown in Table 1 below.

[0136] Viscosity: The viscosity of the positive electrode slurry composition at various shear rates was measured using a rheometer manufactured by Anton Paar GmbH.

[0137] (2) TI: The TI of the positive electrode slurry composition is defined according to Equation 1 below, based on the viscosity measured at various shear rates using a rheometer manufactured by Anton Paar GmbH.

[0138] Equation 1: TI = Log(viscosity at a shear rate of 1 1 / s / viscosity at a shear rate of 10 1 / s) (3) Powder resistivity: The positive electrode slurry composition is cured into powder, and then the powder resistivity is measured using a 4-pin ohmmeter. After applying a constant current to the pins at both ends of the 4-pin ohmmeter, the voltage at the other two pins in the middle is measured to obtain the resistance, which is used to calculate the powder resistivity by reflecting the thickness of the positive electrode and the thickness of the slurry powder.

[0139] Evaluation Example 2: Evaluation of the Positive Electrode The positive electrodes of Examples 1 to 4, as well as Comparative Examples 1 and 2, were evaluated using the following methods, and the results are shown in Table 1 below.

[0140] (1) Adhesion strength (peel): Each positive electrode was cut into 25 mm × 120 mm dimensions to prepare 20 samples. At room temperature, after attaching double-sided tape to the glass substrate, each positive electrode plate was attached to the double-sided tape and rolled. After folding one end of the positive electrode plate to 180°, the positive electrode plate was pulled in the opposite direction at 1.5 mm / sec to measure the force applied to it using a UTM manufactured by Instron.

[0141] Evaluation Example 3: Evaluation of Rechargeable Lithium-ion Battery Cells Each of the rechargeable lithium-ion battery cells of Examples 1 to 4, as well as Comparative Examples 1 and 2, was evaluated using the following methods, and the results are shown in Table 1 below.

[0142] Cycle life characteristics: At 25°C, the rechargeable lithium-ion battery cells were charged / discharged 300 times at a constant current of 0.5C within a voltage range of 2.8V to 4.25V until the lithium metal voltage was reached. Charge and discharge measurements at room temperature were used to calculate capacity retention according to Equation 2 below.

[0143] Equation 2: Capacity retention % = Discharge capacity in the 100th cycle / Discharge capacity in the 1st cycle × 100.

[0144] Table 1:

[0145] The results of Examples 1 to 4, and Comparative Examples 1 and 2, indicate that among the two types of hydrogenated nitrile butadiene rubber derivatives, the hydrogenated nitrile butadiene rubber derivative with a relatively small weight-average molecular weight can constitute a dispersant for conductive materials, while the hydrogenated nitrile butadiene rubber derivative with a relatively large weight-average molecular weight can constitute a binder and replace polyvinylidene fluoride.

[0146] Therefore, positive electrode slurry compositions for rechargeable lithium batteries comprising two types of hydrogenated nitrile butadiene rubber derivatives have advantages in terms of dispersibility, resulting in a small viscosity variation range, which is advantageous in terms of coating processability.

[0147] Therefore, it has been confirmed that positive electrodes and rechargeable lithium battery cells manufactured using positive electrode slurry compositions for rechargeable lithium batteries according to some example embodiments exhibit desired or improved cycle life characteristics.

[0148] While the invention has been described in conjunction with exemplary embodiments now considered practical, it will be understood that the invention is not limited to the disclosed embodiments. Rather, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0149] Description of the tag: 100: Rechargeable lithium battery 10: Positive electrode 11: Positive electrode lead connector 12: Positive electrode terminal 20: Negative electrode 21: Negative electrode lead connector 22: Negative electrode terminal 30: Diaphragm 40: Electrode assembly 50: Casing 60: Sealing component 70: Electrode connector 71: Positive electrode connector 72: Negative electrode connector.

Claims

1. A positive electrode slurry composition for a rechargeable lithium battery, the positive electrode slurry composition comprising: Two types of hydrogenated nitrile butadiene rubber derivatives have different weight-average molecular weights; Conductive materials; Positive electrode active material; as well as Dispersion medium.

2. The positive electrode slurry composition according to claim 1, wherein, The two types of hydrogenated nitrile butadiene rubber derivatives include: The first hydrogenated nitrile butadiene rubber derivative has a weight-average molecular weight in the range of 100,000 g / mol to 400,000 g / mol; and The second hydrogenated nitrile butadiene rubber derivative has a weight-average molecular weight in the range of 250,000 g / mol to 1,000,000 g / mol. The first hydrogenated nitrile butadiene rubber derivative and the second hydrogenated nitrile butadiene rubber derivative have different weight-average molecular weights.

3. The positive electrode slurry composition according to claim 2, wherein: The weight-average molecular weight of the first hydrogenated nitrile butadiene rubber derivative is in the range of 100,000 g / mol to 200,000 g / mol; and The weight-average molecular weight of the second hydrogenated nitrile rubber derivative is in the range of 250,000 g / mol to 1,000,000 g / mol.

4. The positive electrode slurry composition according to claim 2, wherein, The weight ratio of the first hydrogenated nitrile butadiene rubber derivative to the second hydrogenated nitrile butadiene rubber derivative is in the range of 1:1 to 1:

20.

5. The positive electrode slurry composition as described in claim 2, wherein, Based on the total amount of the positive electrode slurry composition (100 wt%): The first hydrogenated nitrile butadiene rubber derivative comprises, in an amount ranging from 0.01 wt% to 0.5 wt%; and The second hydrogenated nitrile rubber derivative is included in an amount ranging from 0.1 wt% to 5 wt%.

6. The positive electrode slurry composition according to claim 2, wherein, The first hydrogenated nitrile butadiene rubber derivative and the second hydrogenated nitrile butadiene rubber derivative each independently comprise: The first structural unit derived from acrylonitrile is represented by chemical formula 1; The second structural unit includes a structural unit derived from hydrogenated butadiene represented by chemical formula 2A and a structural unit derived from butadiene represented by chemical formula 2B. The third structural unit, represented by chemical formula 3; and The fourth structural unit is represented by chemical formula 4: Chemical Formula 1: ； Chemical formula 2A: ； Chemical formula 2B: ； Chemical formula 3: ； Chemical formula 4: ； In chemical formula 3, R 1 Includes one of the following groups: hydrogen; substituted or unsubstituted C1 to C20 alkyl; ester group represented by -COOR, wherein R is a substituted or unsubstituted C1 to C20 alkyl; cyano group represented by -CN; pyrrolidone group represented by -C3H5NHCO; carboxyl group represented by -COOH; or cyano group represented by -NCOC5H 10 The following groups are represented: caprolactam group (represented by -NC4H8O); morpholino group (represented by -OH); amino group (represented by -NH2); vinyl group (represented by -CH=CH2); epoxy group (represented by -COCH2); and thiol group (represented by -SH).

7. The positive electrode slurry composition according to claim 1, wherein, The conductive material includes carbon nanotubes.

8. The positive electrode slurry composition according to claim 2, wherein, The weight ratio of the first hydrogenated nitrile rubber derivative to the conductive material is in the range of 1:1 to 1:

10.

9. The positive electrode slurry composition according to claim 1, wherein: The positive electrode slurry composition comprises, based on a total amount of 100 wt%, the conductive material in an amount equal to or greater than 0 wt% and less than or equal to 5 wt%.

10. The positive electrode slurry composition according to claim 1, wherein, The active material of the positive electrode includes lithium nickel oxide.

11. The positive electrode slurry composition according to claim 1, wherein: The positive electrode slurry composition comprises, based on a total amount of 100 wt%, the positive electrode active material in an amount equal to or greater than 90 wt% to 99.5 wt%.

12. The positive electrode slurry composition according to claim 1, wherein, The dispersion medium includes N-methyl-2-pyrrolidone.

13. The positive electrode slurry composition according to claim 1, wherein, The positive electrode slurry composition has a thixotropic index in the range of 0.2 to 0.7 at 25°C.

14. A positive electrode for a rechargeable lithium battery, the positive electrode comprising: Positive electrode current collector and positive electrode active material layer located on the positive electrode current collector. The positive electrode active material layer includes: Two types of hydrogenated nitrile butadiene rubber derivatives have different weight-average molecular weights; Conductive materials; and Positive electrode active material.

15. A rechargeable lithium battery, said rechargeable lithium battery comprising: The positive electrode as described in claim 14; negative electrode; A diaphragm is located between the positive electrode and the negative electrode; as well as Electrolyte solution.

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