Conductive material dispersion, electrode composition, electrode for rechargeable lithium battery, and rechargeable lithium battery

Abstract

Disclosed are a conductive material dispersion, an electrode composition, an electrode for a rechargeable lithium battery, and a rechargeable lithium battery. The conductive material dispersion includes nanocarbon, a fluorine-containing lithium salt, and a solvent.

Description

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0065987, filed May 21, 2024, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] Disclosed are a conductive material dispersion liquid, an electrode composition, an electrode for a rechargeable lithium battery, and a rechargeable lithium battery. BACKGROUND

[0003] Portable information devices such as cellular phones, laptop computers, smart phones, and the like, or electric vehicles generally use rechargeable lithium batteries having high energy density and portability as a driving power source. Rechargeable lithium batteries having high energy density as a driving power source or a power storage power source can also be used for hybrid vehicles or electric vehicles.

[0004] In order to realize a rechargeable lithium battery suitable for the above-described applications, lithium cobalt-based oxides, lithium nickel-based oxides, lithium nickel-manganese-cobalt composite oxides, lithium nickel-cobalt-aluminum composite oxides, and the like are generally used as a positive electrode active material.

[0005] As a negative electrode active material, various types of carbon-based materials capable of intercalating / deintercalating lithium such as artificial graphite, natural graphite, and hard carbon have been applied, but non-carbon-based negative electrode active materials based on silicon or tin can also be capable of realizing significantly higher capacity. SUMMARY

[0006] Some example embodiments include a conductive material dispersion liquid, an electrode composition, an electrode for a rechargeable lithium battery, and a rechargeable lithium battery that can improve processability by reducing viscosity and increasing solid content.

[0007] In some example embodiments, the conductive material dispersion liquid can include nanocarbon, a fluorine-containing lithium salt, and a solvent.

[0008] In some example embodiments, the electrode composition includes the aforementioned conductive material dispersion liquid and an electrode active material.

[0009] In another example embodiment, an electrode for a rechargeable lithium battery formed of the aforementioned electrode composition is provided.

[0010] In some example embodiments, the rechargeable lithium battery includes a positive electrode, a negative electrode, and an electrolyte, wherein at least one of the positive electrode and the negative electrode is the aforementioned electrode.

[0011] Example embodiments include a conductive material dispersion liquid, an electrode composition, an electrode for a rechargeable lithium battery, and a rechargeable lithium battery, which can improve processability by increasing solid content while reducing viscosity by introducing a fluorine-containing lithium salt in a conductive material dispersion liquid including nano-carbon. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figures 1 to 4 is a cross-sectional view schematically showing a rechargeable lithium battery according to some example embodiments.

[0013] Figure 5 is a graph showing a change in viscosity of a conductive material dispersion liquid according to an amount of a fluorine-containing lithium salt according to some example embodiments. DETAILED DESCRIPTION

[0014] Hereinafter, example embodiments will be described in detail so that those having ordinary skill in the art can easily implement the example embodiments. However, the present disclosure can be implemented in many different forms and is not interpreted as being limited to the example embodiments set forth herein.

[0015] The terms used herein are only used to describe example embodiments and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, singular expressions include plural expressions.

[0016] As used herein, "combinations thereof' means a mixture, a laminate, a composite, a copolymer, an alloy, a blend, a reaction product, or the like of components.

[0017] Here, it should be understood that terms such as "include", "comprise" or "have" are intended to designate the presence of features, numbers, steps, elements or combinations thereof described in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, elements or combinations thereof.

[0018] In the drawings, the thicknesses of layers, films, panels, regions, etc. are exaggerated for clarity, and throughout the specification, like reference numerals refer to like elements. It will be understood that when an element such as a layer, film, region or substrate is referred to as being "on" another element, it can be directly on the other element, or intervening elements can also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

[0019] Further, a "layer" herein includes not only a shape formed on an entire surface when viewed from a plan view, but also a shape formed on a partial surface.

[0020] The average particle diameter can be measured by a method well known to those skilled in the art, for example, by a particle size analyzer, or by a transmission electron microscope image or a scanning electron microscope image. Alternatively, the average particle diameter value can be obtained by measuring using a dynamic light scattering method, performing data analysis, counting the number of particles for each particle size range, and calculating therefrom. Unless otherwise defined, the average particle diameter can represent the diameter (D 50 ) of the particles having 50% of the cumulative volume in the particle size distribution. As used herein, unless otherwise provided by definition, the average particle diameter represents the diameter (D 50 ) of the particles having 50% of the cumulative volume in the particle size distribution obtained by randomly measuring the size (diameter or long axis length) of about 20 particles in a scanning electron microscope image.

[0021] Herein, "or" is not to be construed as exclusive, for example, "A or B" is to be construed as A, B, A+B, etc.

[0022] "Metal" is to be construed as including the concept of ordinary metals, transition metals, and quasi-metals (semimetals).

[0023] When the term "about" or "substantially" is used in this specification in connection with a numerical value, it is intended that the associated numerical value include a tolerance of ±10% around the stated numerical value. When a range is specified, the range includes all values therebetween, such as in increments of 0.1%.

[0024] Conductive material dispersion liquid Example embodiments include a conductive material dispersion liquid including a nanocarbon, a fluorine-containing lithium salt, and a solvent.

[0025] An electrode of an energy storage device including a rechargeable lithium battery includes an electrode active material, a conductive material, and a binder. In general, the electrode is made from or includes a substrate and a mixture that is manufactured by coating a slurry including the electrode active material, the conductive material, and the binder on the substrate, drying the slurry, and then pressing the slurry.

[0026] The nanocarbon is generally used as the conductive material, but because the nanocarbon can not be uniformly dispersed in the slurry and has a property of easily agglomerating, there can be a challenge in that the conductive material can not be uniformly distributed during the manufacture of the electrode. To address this challenge, an example method includes preparing the slurry after first mixing the conductive material with a dispersant in a solvent to form a dispersion of the conductive material.

[0027] The solid content of the slurry is generally determined by the solid content of the conductive material dispersion. A slurry with a high solid content has advantageous effects such as reducing processing costs, improving electrode drying efficiency, improving productivity, improving binder migration, and improving adhesion.

[0028] However, as the solid content of the conductive material dispersion increases to ensure the above-mentioned advantageous effects, the viscosity rapidly increases, which can cause challenges to processability. Therefore, it can be advantageous to develop a conductive material dispersion with a high solid content and a low viscosity.

[0029] Therefore, some example embodiments include a conductive material dispersion that can improve processability by increasing the solid content while reducing the viscosity compared to the prior art.

[0030] To achieve the above-mentioned advantages, the conductive material dispersion can include nanocarbon, a fluorine-containing lithium salt, and a solvent. Here, "dispersion" refers to a state in which the nanocarbon is uniformly distributed within the solvent such that no visible phase separation occurs, and the dispersion can exhibit an electrokinetic potential (Zeta potential or ζ potential) within a defined range (e.g., ±10 mV to ±25 mV), indicating colloidal stability.

[0031] In some example embodiments, the conductive material includes nanocarbon, which is dispersed in a solvent to form a conductive material dispersion.

[0032] When the amount of nanocarbon is increased to increase the solid content of the conductive material dispersion, the viscosity increases due to the nanocarbon, which has a property of easily agglomerating, and the processability deteriorates. Therefore, by adding a fluorine-containing lithium salt to the conductive material dispersion along with the nanocarbon, a colloidal network can be formed while reducing the electrokinetic potential (Zeta potential or ζ potential) on the surface of the nanocarbon particles in the conductive material dispersion. Therefore, when the colloidal network is formed, the viscosity of the conductive material dispersion as a suspension is reduced. Therefore, the fluorine-containing lithium salt can function to reduce the viscosity of the conductive material dispersion. Because of this, the solid content of the conductive material dispersion can be increased, the processability can be improved, and the processing costs can be reduced.

[0033] In some example embodiments, the fluorine-containing lithium salt can include at least one of LiPF6, LiBF4, lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), and combinations thereof. The use of the fluorine-containing lithium salt can achieve the advantageous effect of reducing the viscosity of the conductive material dispersion.

[0034] Representative examples of the fluorine-containing lithium salt can include fluorine-containing imide lithium salts, for example, at least one of lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and combinations thereof. In this case, the effect of reducing the viscosity of the conductive material dispersion liquid due to the addition of the fluorine-containing lithium salt can be improved or maximized.

[0035] As an example, the content of the fluorine-containing lithium salt can be in the range of about 0.001 wt% to about 1 wt%, for example, in the range of about 0.001 wt% to about 0.5 wt%, about 0.005 wt% to about 0.1 wt%, or about 0.005 wt% to about 0.05 wt%, based on 100 wt% of the conductive material dispersion liquid. Within the above ranges, the effect of reducing the viscosity of the conductive material dispersion liquid due to the addition of the fluorine-containing lithium salt can be improved or maximized.

[0036] In some example embodiments, the nanocarbon can include at least one of carbon black, carbon nanotube, fullerene, graphene, and combinations thereof.

[0037] In some example embodiments, the content of the nanocarbon can be in the range of about 1 wt% to about 20 wt%, for example, in the range of about 3 wt% to about 15 wt%, or about 9 wt% to about 12 wt%, based on 100 wt% of the conductive material dispersion liquid. Within the above ranges, the effect of increasing the solid content, improving the processability, and improving the electrical conductivity due to the addition of the nanocarbon can be improved or maximized.

[0038] As an example, the zeta potential of the nanocarbon can be in the range of about ±10 mV to about ±25 mV. When the surface of the particles is charged, electrostatic repulsion occurs, and the electrostatic repulsion can be expressed as the zeta potential. The higher the zeta potential, the higher the repulsive force between the particles. However, the nanocarbon according to some example embodiments exists in the conductive material dispersion liquid together with the fluorine-containing lithium salt, thereby reducing the zeta potential and reducing the repulsive force of the surface of the particles of the conductive material. As a result, a colloidal network can be formed within the conductive material dispersion liquid, improving the dispersibility and effectively reducing the viscosity of the dispersion liquid.

[0039] In some example embodiments, the zeta potential can be measured using a zeta potential measuring device (Zetasizer Nano ZS, Malvern Panalytical). For example, the zeta potential can be measured at 25°C by electrophoretic light scattering (ELS) using a zeta potential measuring device (Zetasizer Nano ZS, Malvern Panalytical).

[0040] In some example embodiments, the solid content in the conductive material dispersion can be or include nano-carbon and a fluorine-containing lithium salt, and the total solid content of the nano-carbon and the fluorine-containing lithium salt can be in a range of about 1 wt% to about 20 wt%, for example, in a range of about 3 wt% to about 15 wt%, about 9 wt% to about 13 wt%, or about 10 wt% to about 12 wt%, based on 100 wt% of the conductive material dispersion. Within the above range, while sufficiently ensuring electrical conductivity, processability can be improved to reduce processing costs and improve drying efficiency, and an effect of improving adhesion is also effectively achieved.

[0041] As an example, the viscosity of the conductive material dispersion can be in a range of about 100 cps to about 2,000 cps, for example, in a range of about 200 cps to about 1,800 cps, about 500 cps to about 1,600 cps, about 900 cps to about 1,500 cps, about 1,000 cps to about 1,400 cps, or about 1,300 cps to about 1,400 cps. The viscosity can be measured at room temperature (20°C to 25°C), and can be measured at a shear rate of 10 s -1 As an example, the viscosity of the conductive material dispersion can be in a range of about 100 cps to about 2,000 cps, for example, in a range of about 200 cps to about 1,800 cps, about 500 cps to about 1,600 cps, about 900 cps to about 1,500 cps, about 1,000 cps to about 1,400 cps, or about 1,300 cps to about 1,400 cps. The viscosity can be measured at room temperature (20°C to 25°C), and can be measured at a shear rate of 10 s -1 When the above viscosity range is satisfied, the conductive material dispersion exhibits an appropriate viscosity, and thus an electrode can be easily manufactured using the conductive material dispersion. Furthermore, by improving processability, processing costs can be reduced, drying efficiency can be improved, and adhesion can be improved.

[0042] In some example embodiments, the conductive material dispersion can have a W value defined by Equation 1, the W value being in a range of about 90 to about 20,000, about 150 to about 20,000, or about 90 to about 5,000, for example, in a range of about 90 to about 2,500, about 90 to about 2,100, or about 600 to about 2,100. In this case, due to the addition of the fluorine-containing lithium salt, a reduction or inhibition of an increase in viscosity of the conductive material dispersion can be achieved, and by the increase in solid content due to the addition of the nano-carbon, an improvement in adhesion can be achieved.

[0043] Equation 1: W = W S / W F .

[0044] In Equation 1, W S represents the weight percent content of the sum of the nano-carbon and the fluorine-containing lithium salt with respect to 100 wt% of the conductive material dispersion, and W Frepresents the content of the fluorine-containing lithium salt in terms of weight percentage with respect to 100 wt% of the conductive material dispersion liquid.

[0045] For example, the solvent can be or include at least one of water; amide polar organic solvents such as dimethylformamide, diethylformamide, dimethylacetamide (DMAC), and N-methylpyrrolidone (NMP); alcohols such as methanol, ethanol, 1-propanol, 2-propanol (isopropanol), 1-butanol (n-butanol), 2-methyl-1-propanol (isobutanol), 2-butanol (sec-butanol), 1-methyl-2-propanol (tert-butanol), pentanol, hexanol, heptanol, or octanol; glycols such as or including at least one of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,5-pentanediol, and hexanediol; polyhydric alcohols such as or including at least one of glycerol, trimethylolpropane, pentaerythritol, and sorbitol; glycol ethers such as or including at least one of ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, and tetraethylene glycol monobutyl ether; ketones such as or including at least one of acetone, methyl ethyl ketone, methyl propyl ketone, and cyclopentanone; and esters such as or including at least one of ethyl acetate, γ-butyrolactone, and ε-propiolactone, and any one of these or a mixture of two or more of these can be used.

[0046] According to some example embodiments, the conductive material dispersion liquid can further include a dispersant, and can be further dispersed after the dispersant is added.

[0047] As an example, the conductive material dispersion liquid can be used in an electrode composition for a rechargeable lithium battery.

[0048] In some example embodiments, the conductive material dispersion liquid can not include an electrode active material. For example, the electrode active material can include at least one of a positive electrode active material and a negative electrode active material. Here, the description described below can apply to the positive electrode active material or the negative electrode active material.

[0049] In some example embodiments, in the conductive material dispersion liquid, the amount of the electrode active material can be less than or equal to 0.5 wt% (including 0 wt%) based on 100 wt% of the conductive material dispersion liquid, for example, less than or equal to 0.3 wt% (including 0 wt%), less than or equal to about 0.1 wt% (including 0 wt%), or 0 wt%.

[0050] Electrode composition In some example embodiments, an electrode composition including the aforementioned conductive material dispersion liquid and an electrode active material is provided.

[0051] In one example, the electrode composition can include a conductive material dispersion liquid and an electrode active material separately prepared.

[0052] As an example, the electrode active material can be prepared separately from the conductive material dispersion liquid, and can be combined with the conductive material dispersion liquid to form the electrode composition.

[0053] As an example, the electrode can be or include at least one of a positive electrode and a negative electrode, for example, a positive electrode.

[0054] Here, the description described below can be applied to the aforementioned positive electrode or negative electrode. When the electrode is a positive electrode, the description of the positive electrode active material is applied to the electrode active material, and when the electrode is a negative electrode, the description of the negative electrode active material can be applied to the electrode active material.

[0055] Electrode for rechargeable lithium battery In some example embodiments, an electrode for a rechargeable lithium battery is provided, which is formed of or includes the aforementioned electrode composition.

[0056] In one example, the electrode can include an electrode current collector and an electrode active material layer located on the electrode current collector and formed of the aforementioned electrode composition.

[0057] For example, the electrode can be or include at least one of a positive electrode and a negative electrode. For example, the electrode can be or include a positive electrode.

[0058] Therefore, when the electrode is a positive electrode, the electrode includes a positive electrode current collector and a positive electrode active material layer located on the positive electrode current collector and formed of the aforementioned electrode composition. For example, the components included in the positive electrode active material layer include nanocarbon and a fluorine-containing lithium salt as solids included in the aforementioned electrode composition. In addition, the components that can be included in the positive electrode active material layer described later can be further included.

[0059] In addition, when the electrode is a negative electrode, the electrode includes a negative electrode current collector and a negative electrode active material layer located on the negative electrode current collector and formed of the aforementioned electrode composition. For example, the components included in the negative electrode active material layer include nanocarbon and a fluorine-containing lithium salt as solids included in the aforementioned electrode composition. In addition, the components that can be included in the negative electrode active material layer described later can be further included.

[0060] Here, the description described later can be applied to the aforementioned positive electrode or negative electrode, and thus, the description described later can be equally applied to the positive electrode current collector, the positive electrode active material layer, the negative electrode current collector, and the negative electrode active material layer.

[0061] Meanwhile, a general method in the related art field can be applied to the method of forming an electrode.

[0062] Rechargeable lithium battery In some example embodiments, a rechargeable lithium battery includes a positive electrode, a negative electrode, and an electrolyte, wherein at least one of the positive electrode and the negative electrode is or includes the aforementioned electrode. As an example, the rechargeable lithium battery can include a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode, and an electrolyte solution.

[0063] According to the shape, the rechargeable lithium battery can be classified into a cylindrical shape, a prismatic shape, a pouch shape, a coin shape, etc. Figures 1 to 4 is a schematic diagram illustrating a rechargeable lithium battery according to some example embodiments, wherein, Figure 1 is a cylindrical battery, Figure 2 is a prismatic battery, Figure 3 and Figure 4 is a pouch battery. Referring to Figures 1 to 4 , the rechargeable lithium battery 100 includes an electrode assembly 40 having a separator 30 interposed between a positive electrode 10 and a negative electrode 20, and a case 50 in which the electrode assembly 40 is accommodated. The positive electrode 10, the negative electrode 20, and the separator 30 can be impregnated with an electrolyte solution (not shown). As Figure 1 indicated in the above, the rechargeable lithium battery 100 can include a sealing member 60 sealing the case 50. Further, in Figure 2 , the rechargeable lithium battery 100 can include a positive electrode lead tab 11, a positive electrode terminal 12, a negative electrode lead tab 21, and a negative electrode terminal 22. As Figure 3 and Figure 4 indicated in the above, the rechargeable lithium battery 100 includes Figure 4 indicated in the above, an electrode tab 70, and Figure 3 indicated in the above, a positive electrode tab 71 and a negative electrode tab 72, the electrode tab 70 / 71 / 72 forming an electrical path for guiding an electric current formed in the electrode assembly 40 to the outside of the rechargeable lithium battery 100.

[0064] Positive electrode The positive electrode 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 can include a positive electrode active material, and can optionally further include a binder, a conductive material, or a combination thereof.

[0065] Positive electrode active material The positive electrode active material can include a compound capable of intercalating and deintercalating lithium (lithiated intercalation compound). For example, at least one of a composite oxide of lithium and a metal such as or including at least one of cobalt, manganese, nickel, and combinations thereof can be used.

[0066] The composite oxide can be or include a lithium transition metal composite oxide, and examples thereof can include at least one of or combinations of lithium nickel-based oxides, lithium cobalt-based oxides, lithium manganese-based oxides, lithium iron phosphate-based compounds, lithium nickel manganese-based oxides free of cobalt, and superlithiated layered oxides.

[0067] For example, the positive electrode active material can be or include a high-nickel positive electrode active material having a nickel content greater than or equal to about 80 mol% based on 100 mol% of metals other than lithium in the lithium transition metal composite oxide. The nickel content in the high-nickel positive electrode active material can be greater than or equal to about 85 mol%, greater than or equal to about 90 mol%, greater than or equal to about 91 mol%, or greater than or equal to about 94 mol% and less than or equal to about 99 mol% based on 100 mol% of metals other than lithium. The high-nickel positive electrode active material can achieve high capacity, and can be applied to high-capacity, high-density rechargeable lithium batteries.

[0068] As another example, a compound represented by any one 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 Coc L 1 d G e O2 (0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4 (0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3 (0≤f≤2); Li a FePO4 (0.90≤a≤1.8).

[0069] In the above chemical formula, 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 is or includes at least one of Mn, Al, and combinations thereof.

[0070] Binder The binder improves the binding properties between the positive electrode active material particles and between the positive electrode active material particles and the current collector. Examples of the binder can include at least one of polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, an oxirane-containing polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, and nylon, but is not limited thereto.

[0071] Conductive material The conductive material is included to provide electrode conductivity, and any conductive material can be used as the conductive material, unless the conductive material causes a chemical change in the battery. Examples of the conductive material can include: a carbon-based material such as or including at least one of natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, or the like; a metal-based material including at least one of a metal powder or a metal fiber of copper, nickel, aluminum, silver, or the like; a conductive polymer such as a polyphenylene derivative; or a mixture thereof.

[0072] The amount of each of the binder and the conductive material can be in the range of about 0.5 wt% to about 5 wt% based on 100 wt% of the positive electrode active material layer.

[0073] The positive electrode current collector can include Al, but is not limited thereto.

[0074] Negative electrode The negative electrode can include a current collector and a negative electrode active material layer on the current collector, the negative electrode active material layer can include a negative electrode active material and can further include a binder, a conductive material, or a combination thereof.

[0075] Negative electrode active material The negative electrode active material can include a material that reversibly intercalates / deintercalates lithium ions, lithium metal, a lithium metal alloy, a material capable of doping / de-doping lithium, or a transition metal oxide.

[0076] The material that reversibly intercalates / deintercalates lithium ions can include, for example, crystalline carbon, amorphous carbon, or a combination thereof as a carbon-based negative electrode active material. The crystalline carbon can be irregular or natural graphite or artificial graphite in a sheet, flake, spherical, or fibrous shape. The amorphous carbon can be or include at least one of soft carbon, hard carbon, mesophase pitch carbonization products, calcined coke, or the like.

[0077] The lithium metal alloy includes an alloy of lithium and 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.

[0078] The material capable of doping / de-doping lithium can be or include at least one of a Si-based negative electrode active material and a Sn-based negative electrode active material. The Si-based negative electrode active material can include silicon, a silicon-carbon composite, SiO x(0 < x < 2), Si-Q alloy (wherein Q is an element such as or including at least one of alkali metal, alkaline earth metal, Group 13 element, Group 14 element (excluding Si), Group 15 element, Group 16 element, transition metal, rare earth element, and combinations thereof, for example, at least one of 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, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, and combinations thereof), or a combination thereof. The Sn-based negative electrode active material can be or include at least one of Sn, Sn02, Sn alloy, and combinations thereof.

[0079] The silicon-carbon composite can be or include at least one of a composite of silicon and amorphous carbon. The average particle diameter (D 50 ) of the silicon-carbon composite particles can be, for example, in a range of about 0.5 pm to about 20 pm. According to some example embodiments, the silicon-carbon composite can be in a form of silicon particles and amorphous carbon coated on surfaces of the silicon particles. For example, the silicon-carbon composite can include secondary particles (cores) in which silicon primary particles are assembled and an amorphous carbon coating layer (shell) on surfaces of the secondary particles. The amorphous carbon can also be present between the silicon primary particles, for example, the silicon primary particles can be coated with the amorphous carbon. The secondary particles can be dispersed in an amorphous carbon matrix.

[0080] The silicon-carbon composite can also include crystalline carbon. For example, the silicon-carbon composite can include a core including crystalline carbon and silicon particles and an amorphous carbon coating layer on surfaces of the core. The crystalline carbon can be or include artificial graphite, natural graphite, or a combination thereof. The amorphous carbon can include at least one of soft carbon or hard carbon, mesophase pitch carbonization product, and calcined coke.

[0081] When the silicon-carbon composite includes silicon and amorphous carbon, the silicon content can be in a range of about 10 wt% to about 50 wt% and the content of the amorphous carbon can be about 50 wt% to about 90 wt% based on 100 wt% of the silicon-carbon composite. Further, when the silicon-carbon composite includes silicon, amorphous carbon, and crystalline carbon, the silicon content can be in a range of about 10 wt% to about 50 wt%, the content of the crystalline carbon can be in a range of about 10 wt% to about 70 wt%, and the content of the amorphous carbon can be in a range of about 20 wt% to about 40 wt% based on 100 wt% of the silicon-carbon composite.

[0082] Further, the thickness of the amorphous carbon coating layer can be in a range of about 5 nm to about 100 nm. The average particle diameter (D 50) can be in the range of about 10 nm to about 1 µm, or about 10 nm to about 200 nm. The silicon particles can be in the form of silicon alone, in the form of a silicon alloy, or in an oxidized form. The oxidized form of silicon can be SiO x (0 < x < 2) represents. At this time, the atomic content ratio of Si:O, which represents the degree of oxidation, can be in the range of about 99:1 to about 33:67. As used herein, the average particle diameter (D 50 ) represents the diameter of the particles of which the cumulative volume is about 50% by volume in the particle size distribution.

[0083] The Si-based negative electrode active material or the Sn-based negative electrode active material can be mixed with the carbon-based negative electrode active material. When the Si-based negative electrode active material or the Sn-based negative electrode active material is mixed and used with the carbon-based negative electrode active material, the mixing ratio can be in the range of about 1:99 to about 90:10 by weight.

[0084] Binder The binder is configured to adhere the negative electrode active material particles to each other, and to adhere 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 a combination thereof.

[0085] 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, polyamide imide, polyimide, and a combination thereof.

[0086] The aqueous binder can include at least one of styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoro rubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and a combination thereof.

[0087] When the aqueous binder is used as the negative electrode binder, a cellulose-based compound capable of imparting tackiness can be further included. As the cellulose-based compound, one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and alkali metal salts thereof can be mixed and used. The alkali metal can be or include at least one of Na, K, and Li.

[0088] The dry binder can be or include a polymeric material capable of becoming fibrous, and can be or include, for example, at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, and combinations thereof.

[0089] Conductive material The conductive material includes a conductive material to provide electrode conductivity, and any conductive material can be used as the conductive material, unless the conductive material causes a chemical change in the battery. Examples of the conductive material include at least one of carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.; metal-based materials including metal powder or metal fiber of at least one of copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0090] The content of the negative electrode active material can be in the range of about 95 wt% to about 99.9 wt% based on 100 wt% of the negative electrode active material layer, and the content of the binder can be in the range of about 0.5 wt% to about 5 wt% based on 100 wt% of the negative electrode active material layer. For example, the negative electrode active material layer can include about 90 wt% to about 99 wt% of the negative electrode active material, about 0.5 wt% to about 5 wt% of the binder, and about 0.5 wt% to about 5 wt% of the conductive material.

[0091] Current collector The negative electrode current collector can include, for example, at least one of indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), and alloys thereof, and can be in the form of a foil, a sheet, or a foam. The thickness of the negative electrode current collector can be in the range of, for example, about 1 μm to about 20 μm, about 5 μm to about 15 μm, or about 7 μm to about 10 μm.

[0092] Electrolyte For example, the electrolyte for the rechargeable lithium battery can be or include an electrolyte solution, which can include a non-aqueous organic solvent and a lithium salt.

[0093] The non-aqueous organic solvent can constitute a medium for transporting ions participating in electrochemical reactions of the battery. The non-aqueous organic solvent can be or include at least one of carbonate-based solvents, ester-based solvents, ether-based solvents, ketone-based solvents, alcohol-based solvents, aprotic solvents, and combinations thereof.

[0094] The carbonate-based solvent can 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), butylene carbonate (BC), or the like. The ester-based solvent can include at least one of methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanolide, methyl hydroxyvalerate, valerolactone, caprolactone, or the like. The ether-based solvent can include at least one of dibutyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, or the like. In addition, the ketone-based solvent can include cyclohexanone or the like. The alcohol-based solvent can include at least one of ethanol, isopropyl alcohol, or the like, and the aprotic solvent can include at least one of a nitrile such as R-CN (wherein R is a C2 to C20 linear, branched, or cyclic hydrocarbon group and can include a double bond, an aromatic ring, or an ether group, or the like); an amide such as dimethylformamide; a dioxolane such as 1,3-dioxolane, 1,4-dioxolane, or the like; a sulfolane; or the like.

[0095] The non-aqueous organic solvent can be used alone or as a mixture of two or more types of solvents, and when used as a mixture of two or more types of solvents, the mixing ratio can be appropriately adjusted according to the desired battery performance, which is widely known to those skilled in the art.

[0096] When using a carbonate-based solvent, a cyclic carbonate and a chain carbonate can be mixed and used, and the cyclic carbonate and the chain carbonate can be mixed in a volume ratio ranging from about 1:1 to about 1:9.

[0097] The non-aqueous organic solvent can further include an aromatic hydrocarbon-based organic solvent. For example, a carbonate-based solvent and an aromatic hydrocarbon-based organic solvent can be mixed and used in a volume ratio ranging from about 1:1 to about 30:1.

[0098] The electrolyte solution can further include at least one of vinyl ethylene carbonate, vinylene carbonate, and an ethylene carbonate-based compound to improve battery cycle life.

[0099] Examples of the ethylene carbonate-based compound can include at least one of fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, and cyanoethylene carbonate.

[0100] Lithium salts dissolved in organic solvents supply lithium ions in batteries, enable basic operation of rechargeable lithium batteries, and improve the transport of lithium ions between the positive electrode and the negative electrode. Examples of lithium salts can include at least one of 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+1 SO2) (wherein x and y are integers of 1 to 20), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluorobis(oxalato)phosphate (LiDFBOP), lithium difluorobis(oxalato)borate (LiDFBOB), and lithium bis(oxalato)borate (LiBOB).

[0101] The concentration of the lithium salt can be in the range of about 0.1 M to about 2.0 M. When the concentration of the lithium salt is in the above range, the electrolyte solution has proper ionic conductivity and viscosity, thus desired or improved performance can be achieved, and lithium ions can move more efficiently.

[0102] Separator According to the type of the rechargeable lithium battery, a separator can be present between the positive electrode and the negative electrode. The separator can include at least one of polyethylene, polypropylene, polyvinylidene fluoride, or a multi-layer film of two or more layers thereof; and a hybrid multi-layer film such as a polyethylene / polypropylene double-layer separator, a polyethylene / polypropylene / polyethylene triple-layer separator, a polypropylene / polyethylene / polypropylene triple-layer separator, and the like.

[0103] The separator can include a porous substrate and a coating layer on one or both surfaces of the porous substrate, the coating layer including an organic material, an inorganic material, or a combination thereof.

[0104] The porous substrate can be or include a polymeric film formed of or including any one of polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetals, polyamides, polyimides, polycarbonates, polyether ketones, polyaryletherketones, polyether ether ketones, polyetherimides, polyamideimides, polybenzimidazoles, polyether sulfones, polyphenylene ethers, cyclic olefin copolymers, polyphenylene sulfides, polyethylene naphthalate, glass fibers, Teflon, and polytetrafluoroethylene, or a copolymer or mixture of two or more thereof, or including any one of or including at least one of the above.

[0105] The porous substrate can have a thickness in a range of about 1 µm to about 40 µm, for example, in a range of about 1 µm to about 30 µm, about 1 µm to about 20 µm, about 5 µm to about 15 µm, or about 10 µm to about 15 µm.

[0106] The organic material can include a (meth)acrylic copolymer including a first structural unit derived from a (meth)acrylamide and a second structural unit including at least one of a structural unit derived from a (meth)acrylic acid or a (meth)acrylate and a structural unit derived from a (meth)acrylamide sulfonic acid or a salt thereof.

[0107] The inorganic material can 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 is not limited thereto. The average particle diameter (D 50 ) of the inorganic particles can be in a range of about 1 nm to about 2000 nm, for example, in a range of about 100 nm to about 1000 nm, or about 100 nm to about 700 nm.

[0108] The organic material and the inorganic material can be mixed in one coating layer, or a coating layer including the organic material and a coating layer including the inorganic material can be stacked.

[0109] The thickness of the coating layer can be in a range of about 0.5 µm to about 20 µm, for example, in a range of about 1 µm to about 10 µm, or about 1 µm to about 5 µm.

[0110] Examples and comparative examples of the present disclosure are described below. However, the following examples are merely examples of the present disclosure, and the present disclosure is not limited to the following examples.

[0111] Example 1 9 wt% of multi-walled carbon nanotubes (MWCNTs) and 0.005 wt% of LiTFSI were mixed in an NMP solvent to prepare a conductive material dispersion.

[0112] 99 wt% of a positive electrode active material (LiCoO2) and 1 wt% of a polyvinylidene fluoride binder were mixed in an NMP solvent to prepare a composition including the positive electrode active material.

[0113] The conductive material dispersion and the composition including the positive electrode active material were mixed at a weight ratio of 1:9 to prepare a positive electrode slurry, and the positive electrode slurry was coated on an aluminum foil current collector, then dried and pressed to manufacture a positive electrode.

[0114] Subsequently, a negative electrode active material layer slurry was prepared by mixing 97.5 wt% of the graphite negative electrode active material, 1.5 wt% of carboxymethyl cellulose, and 1 wt% of styrene butadiene rubber in an aqueous solvent. The negative electrode active material layer slurry was coated on a copper foil current collector, and then dried and pressed to manufacture a negative electrode.

[0115] The positive electrode and the negative electrode were used together with a polytetrafluoroethylene separator and an electrolyte solution prepared by dissolving 1 M LiPF6in a mixed solvent of ethylene carbonate and dimethyl carbonate in a volume ratio of 3:7, thereby manufacturing a rechargeable lithium battery cell in a conventional manner.

[0116] Example 2 The conductive material dispersion liquid, the positive electrode, the negative electrode, and the rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that the conductive material dispersion liquid was prepared by using 9 wt% of multi-walled carbon nanotubes (MWCNTs) and 0.01 wt% of LiTFSI.

[0117] Example 3 The conductive material dispersion liquid, the positive electrode, the negative electrode, and the rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that the conductive material dispersion liquid was prepared by using 9 wt% of multi-walled carbon nanotubes (MWCNTs) and 0.02 wt% of LiTFSI.

[0118] Example 4 The conductive material dispersion liquid, the positive electrode, the negative electrode, and the rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that the conductive material dispersion liquid was prepared by using 9 wt% of multi-walled carbon nanotubes (MWCNTs) and 0.05 wt% of LiTFSI.

[0119] Example 5 The conductive material dispersion liquid, the positive electrode, the negative electrode, and the rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that the conductive material dispersion liquid was prepared by using 9 wt% of multi-walled carbon nanotubes (MWCNTs) and 0.1 wt% of LiTFSI.

[0120] Example 6 The conductive material dispersion liquid, the positive electrode, the negative electrode, and the rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that the conductive material dispersion liquid was prepared by using 9 wt% of multi-walled carbon nanotubes (MWCNTs) and 1 wt% of LiTFSI.

[0121] Comparative Example 1 The conductive material dispersion, positive electrode, negative electrode, and rechargeable lithium battery cell are basically manufactured in the same manner as in Example 1, except that the conductive material dispersion is prepared by using 9 wt% multi-walled carbon nanotubes (MWCNTs) alone.

[0122] Comparative Example 2 The negative electrode and rechargeable lithium battery cell are manufactured in essentially the same manner as in Example 1, except that the positive electrode is manufactured by mixing 98.5 wt% of positive electrode active material (LiCoO2), 1.0 wt% of polyvinylidene fluoride binder and 0.5 wt% of multi-walled carbon nanotube (MWCNT) conductive material to prepare a positive electrode active material layer slurry, instead of preparing a conductive material dispersion and a composition containing positive electrode active material. The positive electrode active material layer slurry is coated onto an aluminum foil current collector, and then dried and pressed.

[0123] Evaluation Example 1: Viscosity evaluation The viscosity changes of each conductive material dispersion in Examples 1 to 6 and Comparative Example 1 were measured according to the amount of fluorinated lithium salt, and the results are presented in... Figure 5 In this study, a rotational rheological viscometer (Rheostress1 model from HÄKKE) was used to measure the viscosity at room temperature (25°C) for 10 seconds. -1 The shear rate is used to measure viscosity.

[0124] like Figure 5 As shown, Comparative Example 1, which prepared a conductive material dispersion without adding a fluorinated lithium salt, exhibited excessively high viscosity. Therefore, the conductive material dispersion of Comparative Example 1 presented challenges in increasing the solid content, as seen in Evaluation Example 2, which will be described below. Unless otherwise stated, all viscosity values ​​described in this specification were measured under the same conditions.

[0125] Conversely, Examples 1 to 6, which prepared conductive material dispersions by adding fluorinated lithium salts, exhibited sufficiently low viscosity. According to the examples above, as shown in Evaluation Example 2 described below, the addition of nano-carbon increased the solid content.

[0126] Evaluation Example 2: Measurement of solid content In the conductive material dispersions of Examples 1 to 5, the solid content was increased by adding nano-carbon while fixing the amount of fluorinated lithium salt until the concentration was 10 s at room temperature (25°C). -1 The viscosity reached 1,300 cps when the shear rate was measured, and these were named Examples 7 to 11 respectively.

[0127] The maximum solid content of Examples 7 to 11 was measured under the above viscosity conditions, and the results are shown in Table 1 below. Here, the solid content indicates the total content of the nanocarbon and the fluorine-containing lithium salt based on 100 wt% of the conductive material dispersion liquid.

[0128] Table 1:

[0129] As shown in Table 1, the conductive material dispersion liquids of Examples 7 to 11 exhibited a higher solid content than the 9 wt% solid content of the conductive material dispersion liquid of Comparative Example 1.

[0130] Accordingly, Examples 7 to 11 including the conductive material dispersion liquid according to some example embodiments exhibited a viscosity similar to that of Comparative Example 1 including the conductive material dispersion liquid but not including the fluorine-containing lithium salt, but the solid content of the example embodiments was further increased compared to that of Comparative Example 1. Thus, the positive electrode manufactured by using such a conductive material dispersion liquid improved the battery performance due to the desired or improved conductivity, but reduced the processing cost and improved the processability. Furthermore, the positive electrode manufactured by using such a conductive material dispersion liquid improved the binder migration and achieved better adhesion.

[0131] Evaluation Example 3: Evaluation of electromotive potential The zeta potential of the nanocarbon in the conductive material dispersion liquids of Example 1 and Example 6 and Comparative Example 1 was measured by using an electrokinetic potential measuring device (Zetasizer Nano ZS, Malvern Panalytical), and the results are shown in Table 2 below.

[0132] Table 2:

[0133] The nanocarbon in the conductive material dispersion liquid of Comparative Example 1 was confirmed to have a zeta potential outside the range of ±10 mV to ±25 mV.

[0134] In contrast, the nanocarbon in the conductive material dispersion liquid of Example 1 was confirmed to have a zeta potential within the range of ±10 mV to ±25 mV, and thus exhibited a desired or improved dispersibility.

[0135] On the other hand, as examined in Evaluation Example 1, the conductive material dispersion liquid of Example 6 was confirmed to have a sufficiently low viscosity, but the dispersibility was deteriorated due to the decrease in the zeta potential thereof.

[0136] Evaluation Example 4: Adhesion evaluation To evaluate the adhesion, the adhesion strength of each of the positive electrodes according to Example 1 and Examples 7 to 11 and Comparative Example 1 was measured by attaching a polyvinyl chloride (PVC) double-sided tape to the positive electrode active material layer formed on the positive electrode current collector and peeling the tape at 10 mm / min to 180°.

[0137] Here, when the adhesion force is greater than 2.5 gf / cm,'is given, when the adhesion force is between 1.8 gf / cm and 2.5 gf / cm,'is given, and when the adhesion force is less than 1.8 gf / cm,'is given, and the results are shown in Table 3 below.

[0138] Table 3:

[0139] As shown in Table 3, the positive electrodes of Examples 1 and 7 to 11 exhibited desired or improved adhesion. In particular, the positive electrodes of Examples 7 to 9 having a high solid content of the conductive material dispersion exhibited much more desired or improved adhesion than the positive electrode of Example 1 having a high solid content of the conductive material dispersion.

[0140] In contrast, the positive electrode of Comparative Example 1 manufactured by preparing the conductive material dispersion without adding the fluorine-containing lithium salt exhibited worse adhesion than Examples 7 to 11.

[0141] While the present disclosure has been described in connection with what is presently considered to be the best examples, it is to be understood that the disclosure is not limited to the disclosed example embodiments. On the contrary, the disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0142] Description of symbols: 100: rechargeable lithium battery; 10: positive electrode 11: positive electrode lead tab; 12: positive electrode terminal 20: negative electrode; 21: negative electrode lead tab 22: negative electrode terminal; 30: separator 40: electrode assembly; 50: case 60: sealing member; 70: electrode tab 71: positive electrode tab; 72: negative electrode tab.

Claims

1. A conductive material dispersion liquid, comprising: a nano-carbon; a fluorine-containing lithium salt; and a solvent. The conductive material dispersion liquid has a viscosity in a range of 100 cps to 2,000 cps.

2. The electroconductive material dispersion liquid according to claim 1, wherein A total solid content of the nano-carbon and the fluorine-containing lithium salt is in a range of 1 wt% to 20 wt% based on 100 wt% of the conductive material dispersion liquid.

3. The electroconductive material dispersion liquid according to claim 1, wherein, The fluorine-containing lithium salt includes at least one of LiPF6, LiBF4, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(oxalato)borate, and lithium difluoro(oxalato)borate.

4. The electroconductive material dispersion liquid according to claim 1, wherein, The fluorine-containing lithium salt includes a fluorine-containing imide-based lithium salt.

5. The electroconductive material dispersion liquid according to claim 1, wherein A content of the fluorine-containing lithium salt is in a range of 0.001 wt% to 1 wt% based on 100 wt% of the conductive material dispersion liquid.

6. The electroconductive material dispersion liquid according to claim 1, wherein The nano-carbon includes at least one of carbon black, carbon nanotube, fullerene, and graphene.

7. The electroconductive material dispersion liquid according to claim 1, wherein An electromotive potential of the nano-carbon is in a range of ±10 mV to ±25 mV.

8. The electroconductive material dispersion liquid according to claim 1, wherein, A content of the nano-carbon is in a range of 1 wt% to 20 wt% based on 100 wt% of the conductive material dispersion liquid.

9. The electroconductive material dispersion liquid according to claim 1, wherein, A W value defined by Equation 1 is in a range of 90 to 20,000:

10. The electroconductive material dispersion liquid according to claim 1, wherein Equation 1: W = (1 - z)2 / (z2) The conductive material dispersion liquid is used in an electrode composition for a rechargeable lithium battery. W = W S W F and wherein, in Equation 1, W S represents the weight percentage content of the sum of the nanocarbon and the fluorine-containing lithium salt with respect to 100 wt% of the conductive material dispersion liquid, and W F represents the weight percentage content of the fluorine-containing lithium salt with respect to 100 wt% of the conductive material dispersion liquid.

11. The electroconductive material dispersion liquid according to claim 1, wherein An electrode active material is not included in the conductive material dispersion liquid.

12. The electroconductive material dispersion liquid according to claim 1, wherein, 13.An electrode composition, comprising: the conductive material dispersion liquid according to any one of claims 1 to 12; and an electrode active material. An electrode to which the electrode composition is used is a positive electrode. 15.An electrode for a rechargeable lithium battery, comprising the electrode composition according to claim 13.

14. The electrode composition of claim 13, wherein, 16.A rechargeable lithium battery, comprising: a positive electrode; a negative electrode; and an electrolyte; wherein at least one of the positive electrode and the negative electrode includes the electrode for a rechargeable lithium battery according to claim 15. ​ ​ ​

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