WO2017043919A1 - Matériau conducteur pour batterie secondaire, et batterie secondaire le contenant - Google Patents

Matériau conducteur pour batterie secondaire, et batterie secondaire le contenant Download PDF

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WO2017043919A1
WO2017043919A1 PCT/KR2016/010173 KR2016010173W WO2017043919A1 WO 2017043919 A1 WO2017043919 A1 WO 2017043919A1 KR 2016010173 W KR2016010173 W KR 2016010173W WO 2017043919 A1 WO2017043919 A1 WO 2017043919A1
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Prior art keywords
secondary battery
conductive material
carbon nanotubes
carbon
metal
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PCT/KR2016/010173
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English (en)
Korean (ko)
Inventor
강경연
설종헌
우지희
김예린
조동현
최상훈
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주식회사 엘지화학
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Priority claimed from KR1020160115896A external-priority patent/KR101923466B1/ko
Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority to JP2018503498A priority Critical patent/JP6598223B2/ja
Priority to EP16844735.7A priority patent/EP3349280B1/fr
Priority to CN201680034406.9A priority patent/CN107735890B/zh
Priority to US15/578,177 priority patent/US10665890B2/en
Publication of WO2017043919A1 publication Critical patent/WO2017043919A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a secondary battery conductive material having excellent dispersibility and a secondary battery comprising the same.
  • lithium secondary batteries having high energy density and voltage, long cycle life, and low self discharge rate have been commercialized and widely used.
  • an electrode for a high capacity lithium secondary battery research is being actively conducted on a method for improving an electrode density to produce an electrode having a higher energy density per unit volume.
  • the high-density electrode is formed by molding electrode active material particles having a size of several micrometers to several tens of micrometers by a high pressure press, so that the particles are deformed, the space between the particles is reduced, and electrolyte permeability is easily degraded.
  • the electrically conductive material which has the intensity
  • the conductive material is dispersed between the compressed electrode active material to maintain fine pores between the active material particles to facilitate penetration of the electrolyte, and to reduce the resistance in the electrode with excellent conductivity.
  • the use of carbon nanotubes, which are fibrous carbon-based conductive materials, which can further reduce electrode resistance by forming an electrically conductive path in the electrode has recently increased.
  • Carbon nanotubes which are a kind of fine carbon fibers, are tubular carbons having a diameter of 1 ⁇ m or less, and are expected to be applied to various fields due to their high conductivity, tensile strength and heat resistance due to their specific structures.
  • carbon nanotubes have limited use due to their low solubility and dispersibility. That is, the carbon nanotubes do not form a stable dispersion state in the aqueous solution due to the strong van der Waals attraction between each other, there is a problem that agglomeration phenomenon occurs.
  • the first problem to be solved by the present invention is to provide a secondary battery conductive material having excellent dispersibility.
  • a second problem to be solved by the present invention is to provide a secondary battery electrode, a lithium secondary battery, a battery module and a battery pack including the conductive material.
  • a carbon nanotube unit having a diameter of 20nm to 150nm has an entangled spherical secondary structure, true density (TD) and bulk
  • a conductive material for a secondary battery including carbon nanotubes having a density ratio (TD / BD) of 30 to 120 and a metal content of 50 ppm or less.
  • a carbon nanotube is prepared by contacting a supported catalyst having a metal catalyst supported on an ⁇ -alumina support with a carbon source at a temperature of at least 650 ° C. and less than 800 ° C .; And it provides a method for producing a secondary battery conductive material comprising the step of removing the metal impurities in the carbon nanotubes by chlorination.
  • a lithium secondary battery electrode and a lithium secondary battery comprising the conductive material.
  • a battery module including the lithium secondary battery as a unit cell and a battery pack including the same.
  • the conductive material for a secondary battery according to the present invention may include a large diameter carbon nanotube unit and at the same time have a low density, thereby exhibiting excellent dispersibility in the composition of the composition for forming an electrode for a secondary battery.
  • the conductive material and the electrode including the same as a conductive material are particularly required for batteries requiring high capacity and long life, such as automotive batteries or power tool batteries, particularly batteries requiring minimal performance deterioration at room temperature and low temperature, such as automotive batteries. useful.
  • FIG. 1A is a photograph of a conductive material prepared in Example 1-1 using a scanning electron microscope, and FIG. 1B is a partially enlarged view thereof.
  • FIG. 2A is a photograph of the conductive material prepared in Comparative Example 1-1 using a scanning electron microscope
  • FIG. 2B is a partially enlarged view thereof.
  • Example 3 is a graph showing the results of measuring powder resistance of the conductive material prepared in Example 1-1 and Comparative Example 1-1.
  • FIG. 4 is a graph showing the results of observing the rate characteristic at room temperature (25 ° C.) of the lithium secondary batteries prepared in Examples 2-1 and Comparative Examples 2-1 and 3.
  • FIG. 4 is a graph showing the results of observing the rate characteristic at room temperature (25 ° C.) of the lithium secondary batteries prepared in Examples 2-1 and Comparative Examples 2-1 and 3.
  • FIG. 4 is a graph showing the results of observing the rate characteristic at room temperature (25 ° C.) of the lithium secondary batteries prepared in Examples 2-1 and Comparative Examples 2-1 and 3.
  • FIG. 5 is a graph showing results of observing output characteristics during discharge at room temperature (25 ° C.) of lithium secondary batteries prepared in Examples 2-1 and Comparative Examples 2-1 and 3.
  • FIG. 5 is a graph showing results of observing output characteristics during discharge at room temperature (25 ° C.) of lithium secondary batteries prepared in Examples 2-1 and Comparative Examples 2-1 and 3.
  • FIG. 6 is a graph illustrating results of observing output characteristics during discharge at low temperature (-20 ° C) of the lithium secondary batteries manufactured in Examples 2-1 and Comparative Examples 2-1 and 3.
  • FIG. 6 is a graph illustrating results of observing output characteristics during discharge at low temperature (-20 ° C) of the lithium secondary batteries manufactured in Examples 2-1 and Comparative Examples 2-1 and 3.
  • the term 'bundle type' refers to a secondary shape in the form of a bundle or rope in which a plurality of CNT units are arranged side by side or spirally twisted, unless otherwise stated. do.
  • non-bundle type or “entangled type” refers to a form in which a plurality of CNT units are entangled without being limited to a specific orientation.
  • the conductive material according to the embodiment of the present invention has a spherical secondary structure in which carbon nanotube units having a diameter of 20 nm to 150 nm are entangled, and have true density (TD) and bulk density (BD). And carbon nanotubes having a ratio (TD / BD) of 30 to 120 and a metal content of 50 ppm or less.
  • the conductive material for a secondary battery according to an embodiment of the present invention includes carbon nanotubes including a large diameter carbon nanotube unit but having a low density and exhibiting excellent dispersibility, thereby increasing conductivity in an electrode. It is possible to improve battery performance, in particular battery performance at room temperature and low temperature.
  • the carbon nanotubes have a secondary structure having a spherical shape in which carbon nanotube units are entangled.
  • the term “spherical” or “spherical” includes a case where the shape is substantially spherical in addition to the shape of a sphere, and may include a case where the cross section has an elliptic shape such as a potato shape.
  • the spherical carbon nanotubes have a long axis and a short axis length passing through the particle center in the carbon nanotube particles measured by an average circularity using a flow particulate analyzer or observed through a scanning electron micrograph. When the average circularity is obtained from the ratio (length ratio of major axis / short axis), the value may be 0.9 to 1.0.
  • the carbon nanotube unit has a graphite sheet having a nano-size diameter cylinder shape, and has a sp 2 bond structure.
  • the graphite surface may exhibit characteristics of a conductor or a semiconductor depending on the angle and structure of the surface.
  • the carbon nanotube unit may be a single-walled carbon nanotube (SWCNT), a double-walled carbon nanotube (DWCNT) and a multi-walled carbon nanotube (MWCNT, multi-walled carbon nanotubes).
  • SWCNT single-walled carbon nanotube
  • DWCNT double-walled carbon nanotube
  • MWCNT multi-walled carbon nanotube
  • the carbon nanotubes may include any one or two or more of the single-walled, double-walled and multi-walled carbon nanotube units, more specifically,
  • the multi-walled carbon nanotube unit may include 20 wt% or more based on the total weight of the carbon nanotubes.
  • the diameter of the carbon nanotube unit when the diameter of the carbon nanotube unit is too large as the secondary battery conductive material, the pore diameter of the electrode is too large, the electrode density may be lowered.
  • the diameter of the carbon nanotube unit used is too small, the dispersed carbon nanotube unit or carbon nanotube is buried in the space between the electrode active material particles, it is difficult to form sufficient pores.
  • the diameter of the unit in the carbon nanotubes usable in the present invention may be specifically 20 nm to 150 nm, considering the effect of improving the dispersibility of the conductive material and reducing the resistance of the electrode by controlling the diameter of the unit, the carbon The diameter of the nanotube unit may be more specifically 20nm to 80nm.
  • the length of the carbon nanotube unit is not particularly limited, but as the length of the carbon nanotube is longer, electrical conductivity, strength, and electrolyte storage retention of the electrode may be improved. However, when the length of a carbon nanotube is too long, there exists a possibility that a dispersibility may fall. Accordingly, the length of the unit in the carbon nanotubes usable in the present invention may be specifically 0.5 ⁇ m to 100 ⁇ m. In addition, in consideration of the diameter of the carbon nanotube unit, the carbon nanotube unit may have an aspect ratio defined as the ratio of the carbon nanotube length and the diameter of 5 to 50,000, and more specifically 10 to 15,000.
  • the carbon nanotube unit may improve the electrical conductivity, strength, and electrolyte storage retention of the electrode in the branched phase, but when the amount thereof is too large, dispersibility may decrease. Accordingly, it is desirable to appropriately control the content of the branched tannonanotube units in the carbon nanotubes, which is possible through a grinding process performed during or after the production of the carbon nanotubes.
  • the carbon nanotubes including the carbon nanotube units as described above may have a ratio of true density and bulk density (TD / BD) of 30 to 120.
  • the lower the bulk density of the carbon nanotubes may exhibit excellent dispersibility, but if the bulk density is too low, it is difficult to prepare a high concentration dispersion due to the high viscosity increase during the dispersion process of the carbon nanotubes.
  • the true density of the conductive material if the true density of the conductive material is too small, there are many gaps and the surface area of the conductive material increases, so that the electrical conductivity of the battery is lowered. Can be.
  • the ratio between the true density and the bulk density of the carbon nanotubes usable in the present invention may be 40 to 60.
  • the bulk density of the carbon nanotubes may be determined according to Equation 1 below, and the bulk density of the carbon nanotubes usable in the present invention may be specifically 20 kg / m 3 to 80 kg / m 3 .
  • the bulk density of the carbon nanotubes is measured after weighing the carbon nanotubes in a 20 ml container, from which the bulk density can be calculated according to Equation (1).
  • the conductive material usable in the present invention simultaneously controls the diameter and bulk density of the carbon nanotube unit described above, but includes a large diameter carbon nanotube unit but has a low density and excellent dispersibility without fear of lowering the electrical conductivity in the electrode. Can be represented.
  • the bulk density of the carbon nanotubes is more specifically 30kg / m 3 ⁇ 70kg / m 3 , more specifically 30kg / m 3 ⁇ 60kg / m 3 days Can be.
  • the true density of the carbon nanotubes usable in the present invention is specifically under the conditions satisfying the true density / bulk density ratio. May be from 2100 kg / m 3 to 2500 kg / m 3 .
  • the true density of the carbon nanotubes may be measured according to a conventional true density measuring method, and specifically, may be measured using the AccuPycII-1340 device of Micromeritics.
  • the carbon nanotubes usable in the present invention have a low BET specific surface area because the diameter of the unit has a large diameter as described above, and as a result can exhibit excellent dispersibility.
  • the BET specific surface area of the carbon nanotube can be used in the present invention may be 30m 2 / g to 120m 2 / g, may be more particularly to 30m 2 / g to 85m 2 / g.
  • the specific surface area of the carbon nanotubes is measured by the BET method, and specifically, it can be calculated from the nitrogen gas adsorption amount under the liquid nitrogen temperature (77K) using BELSORP-mino II manufactured by BEL Japan. have.
  • the carbon nanotubes of the spherical secondary structure in which the carbon nanotube units are entangled may have an average particle diameter (D 50 ) of 200 ⁇ m to 800 ⁇ m.
  • the average particle diameter (D 50 ) of the carbon nanotubes may be defined as the particle size at 50% of the particle size distribution.
  • the average particle diameter (D 50 ) of the carbon nanotube particles can be measured using, for example, a scanning electron microscope or a laser diffraction method, more specifically, when measured by a laser diffraction method, After dispersing the carbon nanotubes in a solution, a commercially available laser diffraction particle size measuring apparatus (eg, Microtrac MT 3000) may be introduced to calculate an average particle diameter (D 50 ) based on 50% of the particle size distribution.
  • a commercially available laser diffraction particle size measuring apparatus eg, Microtrac MT 3000
  • the carbon nanotubes may have a particle size distribution (D cnt ) defined by Equation 2 below 0.5 to 1.0.
  • Dn 90 is a number average particle diameter measured under 90% in absorption mode using a Microtrac particle size analyzer with carbon nanotubes in distilled water
  • Dn 10 is a number average particle diameter measured under 10% in standard
  • 50 is the number average particle diameter measured on a 50% basis.
  • the carbon nanotubes may contain 50 ppm or less, more specifically 5 ppm or less, of metal elements derived from a main catalyst or promoter, such as Fe, Co, Mo, V, or Cr, used in the manufacturing process. .
  • the carbon nanotubes may have a volume resistivity of 0.01 ohm ⁇ cm to 0.02 ohm ⁇ cm at a powder density of 0.9 g / cc to 1.5 g / cc.
  • the carbon nanotube according to the present invention exhibits the above-described volume resistance under the conditions of the powder density, thereby lowering the resistance in the electrode when the electrode is applied, and as a result, the battery performance may be improved.
  • the conductive material according to an embodiment of the present invention including the carbon nanotubes described above may be manufactured using a conventional method such as an arc discharge method, a laser evaporation method, or a chemical vapor deposition method.
  • the above-described physical properties may be implemented through control of a heat treatment temperature and an atmosphere or a method of removing impurities.
  • the conductive material is a step of preparing a carbon nanotube by contacting a supported catalyst carrying a metal catalyst on the ⁇ -alumina support with a carbon source at a temperature of 650 °C to less than 800 °C (step 1); And it may be prepared by a manufacturing method comprising the step of removing the metal impurities in the carbon nanotubes by chlorination (step 2).
  • step 1 for the production of the conductive material is carbon by growing carbon nanotubes by chemical vapor phase synthesis by decomposition of a carbon source using a supported catalyst on which a metal catalyst is supported on the ⁇ -alumina support. Step of preparing nanotubes.
  • the supported catalyst is introduced into a horizontal fixed bed reactor or a fluidized bed reactor, and the carbon is heated at a temperature above the thermal decomposition temperature of the gaseous carbon source to below the melting point of the supported metal catalyst.
  • Source or by injecting a mixture of the carbon source and a reducing gas and a carrier gas.
  • the carbon source is thermally decomposed by heat at a high temperature and then permeates into the supported catalyst.
  • the pyrolytic carbon source penetrated into the supported catalyst is saturated, carbons are precipitated from the saturated supported catalyst to form a hexagonal ring structure.
  • the carbon nanotubes produced by the above chemical vapor phase synthesis method have a crystal growth direction substantially parallel to the tube axis and high crystallinity of the graphite structure in the tube length direction. As a result, the diameter of the unit is small, and the electrical conductivity and strength are high.
  • vapor grown carbon nanotubes may have many irregularities and rough portions on the surface thereof. Accordingly, when the electrode is formed, it may exhibit excellent adhesion to the electrode active material.
  • the carbon-based material is used as the electrode active material for the negative electrode of the secondary battery, the gas-grown carbon nanotubes exhibit higher adhesion to the carbon-based active material. It can be adhered to the carbon-based active material without being separated can maintain electrical conductivity and further improve cycle characteristics.
  • the production of the carbon nanotubes may be carried out at a temperature of more than 650 °C 800 °C, more specifically at 650 °C to 700 °C.
  • a temperature of more than 650 °C 800 °C more specifically at 650 °C to 700 °C.
  • dispersibility may be further improved due to the decrease in the bulk density.
  • a heat source for the heat treatment induction heating, radiant heat, laser, infrared (IR), microwave, plasma or surface plasmon heating may be used.
  • carbon may be supplied to the carbon source and may be used without particular limitation as long as it can exist in the gas phase at a temperature of 300 ° C. or higher.
  • it may be a carbon-based compound having 6 or less carbon atoms, more specifically carbon monoxide, methane, ethane, ethylene, ethanol, acetylene, propane, propylene, butane, butadiene, pentane, pentene, cyclopentadiene, hexane, cyclohexane, Benzene, toluene, and the like, and any one or a mixture of two or more thereof may be used.
  • the mixed gas of the reducing gas and the carrier gas transports a carbon source, prevents carbon nanotubes from burning at a high temperature, and assists decomposition of the carbon source.
  • the reducing gas may be a known reducing gas, and specifically, hydrogen may be cited.
  • the carrier gas may be one that is usually used as a carrier gas in the production of carbon nanotubes, specifically, nitrogen and the like.
  • gaseous carbon sources, reducing gases and carrier gases can be used in various volume ratios.
  • the gaseous carbon source may be used in a volume ratio of 0.5 to 1.5 based on one volume of reducing gas
  • the carrier gas may be used in a volume ratio of 0.5 to 1.5 based on one volume of reducing gas.
  • the flow rate of the mixed gas including the carbon source, the reducing gas, and the carrier gas may be appropriately selected in the range of 50 sccm to 10,000 sccm.
  • a cooling process for more regularly aligning the arrangement of the carbon nanotubes is selectively performed.
  • the cooling process may be performed using natural cooling or a cooler according to the removal of the heat source.
  • the supported catalyst used for the production of the conductive material is a metal catalyst supported on a spherical ⁇ -alumina support.
  • ⁇ -alumina has a very low porosity compared with ⁇ -alumina, and thus has low utility as a catalyst support.
  • the firing temperature when preparing a supported catalyst including ⁇ -alumina as a support it is possible to increase the diameter by reducing the specific surface area while suppressing the generation of amorphous carbon in the synthesis of carbon nanotubes.
  • the bulk density of carbon nanotubes can be reduced to improve dispersibility.
  • the ⁇ - alumina is available as a support in the present invention in which the average particle diameter (D 50) 20 ⁇ m to 200 ⁇ m, may be one having a BET specific surface area of 1m 2 / g to 50m 2 / g.
  • the ⁇ -alumina may have a very low porosity, specifically, a porosity of 0.001 cm 3 / g to 0.1 cm 3 / g.
  • the supported catalyst comprising the spherical ⁇ -alumina as a support may be prepared by baking the metal catalyst on the spherical ⁇ -alumina support. Specifically, the supported catalyst is carried out by adding and mixing the spherical ⁇ -alumina support to a metal catalyst precursor solution prepared by dissolving the precursor of the metal catalyst in water, followed by calcining at a temperature of 600 ° C. or lower. Can be.
  • the metal catalyst supported on the support serves to help the carbon components present in the gaseous carbon source combine with each other to form a six-membered ring structure.
  • a main catalyst such as iron (Fe), nickel (Ni) or cobalt (Co) may be used alone, or the main catalyst may be molybdenum (Mo), vanadium (V), chromium (Cr), or the like. It may also be used in the form of a main catalyst-catalyst complex catalyst with a promoter of.
  • the complex catalyst may be FeCO, CoMo, CoV, FeCoMo, FeMoV, FeV or FeCoMoV, etc. Any one or a mixture of two or more thereof may be used.
  • the cocatalyst may be used in an amount of 0.01 mol to 1 mol, more specifically 0.05 mol to 0.5 mol with respect to 1 mol of the main catalyst.
  • a metal salt or metal oxide soluble in water may be used as a precursor of the metal catalyst.
  • the precursor of the metal catalyst may be used in an aqueous solution dissolved in water, in which case, the concentration of the metal catalyst precursor in the aqueous solution may be appropriately adjusted in consideration of the impregnation efficiency. Specifically, the concentration of the metal catalyst precursor in the aqueous solution may be 0.1 g / ml to 0.4 g / ml.
  • an organic acid may be selectively used in addition and mixing of the ⁇ -alumina support in the aqueous solution containing the metal catalyst precursor to control the bulk density of the carbon nanotubes.
  • the metal catalyst precursor solution may be used in an amount corresponding to 3 to 40 moles, more specifically 5 to 30 moles, of the metal catalyst with respect to 1 mole of the organic acid.
  • the organic acid may be citric acid, or the like, or a mixture of two or more kinds may be used.
  • the mixing process of the metal catalyst precursor solution and the spherical ⁇ -alumina support may be performed according to a conventional method, and specifically, may be performed by rotating or stirring under a temperature of 45 ° C. to 80 ° C.
  • the metal catalyst precursor and the support may be mixed in consideration of the content of the metal catalyst supported on the finally prepared supported catalyst.
  • the supported amount of the metal catalyst in the supported catalyst increases, the bulk density of the carbon nanotubes produced using the supported catalyst tends to increase.
  • the metal catalyst may be mixed to be supported in an amount of 5% by weight to 30% by weight based on the total weight of the supported catalyst.
  • a drying process may be optionally further performed prior to the firing process.
  • the drying process may be performed according to a conventional method, specifically, may be carried out by rotary evaporation under vacuum at a temperature of 40 °C to 100 °C for 3 minutes to 1 hour.
  • firing is performed on the mixture of the metal catalyst precursor and the support prepared in the above manner.
  • the firing can be carried out under air or an inert atmosphere at temperatures of up to 600 ° C, specifically 400 ° C to 600 ° C.
  • a preliminary firing process may be optionally further performed at a temperature of 250 ° C. to 400 ° C. after the drying process and before the firing process.
  • the supported catalyst on which the above-described metal catalyst is supported on the aluminum-based support can be obtained.
  • the supported catalyst has a structure in which one or two or more layers of metal catalysts are coated on the surface of a spherical ⁇ -alumina support, and they may have a continuous coating layer structure or a discontinuous coating structure. have. More specifically, it may have a discontinuous coating structure.
  • the supported catalyst may have an average particle diameter (D 50 ) of 30 ⁇ m to 150 ⁇ m and a BET specific surface area of 1 m 2 / g to 50 m 2 / g.
  • the supported catalyst may have a surface roughness of 10nm to 50nm when scanning electron microscope (SEM) observation.
  • the supported catalyst has a number average particle size measured value of 5% or less, specifically 3% or less, when the particle size of 32 ⁇ m or less is defined as an ultrasonic fraction in consideration of the average particle diameter of the ⁇ -alumina support. Can be.
  • the ultrasonic fine powder is an agglomerate of metal catalysts attached to the supported catalyst in the form of islands, and does not come out when sifted, but is separated out at the time of ultrasonic because it is weakly bound to the supported catalyst. These materials differ in particle size and catalyst activity from metal catalysts well coated on supports.
  • the ultrasonic differential amount means the number average particle diameter differential amount measured by the particle size analyzer after the ultrasonic treatment.
  • step 2 is a step of removing the metal impurities in the carbon nanotubes prepared by using the supported catalyst in step 1.
  • step 2 may be performed by chlorination of a metal present as an impurity in the carbon nanotubes prepared in step 1 and then evaporation at a high temperature.
  • metal components in the carbon nanotubes can be removed to 50 ppm or less without fear of deterioration of physical properties of the carbon nanotubes due to defects.
  • physical properties such as bulk density and powder density of the carbon nanotubes may be further changed and controlled.
  • the removal of the metal impurities the step of contacting the carbon nanotubes prepared in step 1 with a chlorine source at a temperature of 450 °C to 900 °C under a nitrogen atmosphere or a vacuum atmosphere to chlorinate the metal in the carbon nanotubes; And heating and evaporating and removing the resulting chlorinated metal.
  • the metal impurity removal process may be performed using a fluidized bed reactor and a static furnace. Specifically, after filling the carbon nanotubes in the reactor of the quartz tube capable of gas inlet and outlet, the temperature is raised to 450 °C to 900 °C using a static furnace in nitrogen or vacuum atmosphere, and the chlorine source is supplied through the gas inlet
  • the carbon nanotubes By contacting the carbon nanotubes can be carried out by chlorination of the metal impurities in the carbon nanotubes, followed by increasing the temperature in the reactor and then evaporating the chlorinated metals under nitrogen atmosphere or under vacuum atmosphere.
  • Cl 2 or CHCl 3 may be used as the chlorine source.
  • the heat treatment temperature for evaporating the chlorinated metal may be 800 °C to 1500 °C. If the heat treatment temperature is less than 800 ° C, the removal efficiency of the chlorinated metal may be lowered. If the heat treatment temperature is higher than 1500 ° C, side reaction may occur.
  • the main catalyst such as Fe, Ni or Co, or the promoter-derived metal impurities in the carbon nanotubes may be reduced to 50 ppm or less, more specifically, 5 ppm or less.
  • the content of metal impurities remaining in the carbon nanotubes can be analyzed using an inductively coupled plasma (ICP).
  • the conductive material including the carbon nanotubes prepared according to the manufacturing method as described above may include a large diameter carbon nanotube unit and exhibit low density, thereby exhibiting excellent dispersibility in the composition during the preparation of the composition for forming an electrode of a secondary battery. .
  • the conductive material according to an embodiment of the present invention may further include a particulate carbon-based material together with the carbon nanotubes.
  • the particulate matter means a particle having a predetermined form, independently present and separable.
  • the particulate carbon-based material may have various shapes such as spherical shape, elliptical shape, conical shape, scale shape or fibrous shape, and specifically, have a spherical shape or substantially spherical shape having an elliptical shape in cross section like a potato shape. It includes the case having.
  • the particulate carbonaceous material has an average circularity of 0.9 to 1.0 obtained by using a flow particulate analyzer or through a length ratio of the long axis and the short axis (length ratio of the long axis / short axis) observed after observation of the runner electron microscope. It may be.
  • the particulate carbonaceous material may be specifically spherical particles having an average particle diameter (D 50 ) of 10 nm to 45 nm and a BET specific surface area of 40 m 2 / g to 170 m 2 / g.
  • D 50 average particle diameter
  • the reactivity can be improved by increasing the electron supply property at the three-phase interface between the electrode active material and the electrolyte during electrode production.
  • the average particle diameter of the particulate carbonaceous material is less than 10 nm, or if the BET specific surface area exceeds 170 m 2 / g, the dispersibility in the electrode mixture is greatly reduced by aggregation of the particulate carbonaceous materials, and the average particle diameter exceeds 45 nm or Alternatively, when the BET specific surface area is only 40 m 2 / g, the size may be excessively large and partially biased in the conductive material arrangement according to the porosity of the positive electrode active material without being uniformly dispersed throughout the positive electrode mixture.
  • the particulate carbonaceous material has an average particle diameter (D 50 ) of 30nm to 45nm, BET specific surface area It may be 40m 2 / g to 120m 2 / g.
  • the specific surface area of a particulate carbonaceous material can be computed from the nitrogen gas adsorption amount under liquid nitrogen temperature (77K) using BELSORP-mino II by BEL Japan.
  • the average particle diameter (D 50 ) of the particulate carbonaceous material may be defined as the particle size based on 50% of the particle size distribution.
  • the average particle diameter (D 50 ) of the particulate carbonaceous material can be measured using, for example, a laser diffraction method. More specifically, after dispersing the conductive material in a solution, it is commercially available. It can be introduced into a laser diffraction particle size measuring device (for example, Microtrac MT 3000) to calculate the average particle diameter (D 50 ) at 50% of the particle size distribution.
  • the particulate carbonaceous material may be used without particular limitation as long as it has conductivity and satisfies its morphological conditions. However, considering that the particulate carbonaceous material is excellent in improving the effect of using the particulate conductive material, the particulate carbonaceous material may be non-graphite carbon. It may be a substance. Specifically, the particulate carbonaceous material may be carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, summer black, or denka black, and any one or a mixture of two or more thereof may be used. . More specifically, the particulate carbonaceous material may be carbon black in consideration of the remarkable improvement effect when used in combination with the carbon nanotubes.
  • the particulate carbonaceous material may be included by being simply mixed with the carbon nanotubes in the conductive material according to an embodiment of the present invention, or may be included in a complex manner by coating or the like.
  • the particulate carbon-based material may be included in 50 parts by weight to 200 parts by weight with respect to 100 parts by weight of carbon nanotubes. When included in the above content range, it is possible to further improve the battery characteristics improvement effect of the mixed use.
  • a secondary battery electrode including the conductive material.
  • the secondary battery electrode may be a positive electrode or a negative electrode, and more specifically, may be a positive electrode.
  • the electrode may be manufactured according to a conventional method except for including the conductive material described above.
  • the positive electrode when the electrode is a positive electrode, the positive electrode includes a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector.
  • the positive electrode current collector is not particularly limited as long as it has conductivity without causing chemical changes in the battery.
  • carbon, nickel, titanium on the surface of aluminum or stainless steel Or surface treated with silver or the like can be used.
  • the positive electrode current collector may have a thickness of typically 3 ⁇ m to 500 ⁇ m, and may form fine irregularities on the surface of the current collector to increase adhesion of the positive electrode active material.
  • it can be used in various forms, such as a film, a sheet, a foil, a net, a porous body, a foam, or a nonwoven body.
  • the cathode active material layer formed on the cathode current collector may further include a cathode active material, a conductive material, and optionally a binder.
  • the cathode active material may be a compound capable of reversible intercalation and deintercalation of lithium (lithiated intercalation compound), and specifically, a metal of lithium with cobalt, manganese, nickel, or a combination thereof It may be a composite metal oxide.
  • the positive electrode active material is a lithium-manganese oxide (eg, LiMnO 2 , LiMn 2 O Etc.), lithium-cobalt-based oxides (e.g., LiCoO 2, etc.), lithium-nickel-based oxides (e.g., LiNiO 2, etc.), lithium-nickel-manganese-based oxides (e.g., LiNi 1 - Y Mn Y O 2 (where, 0 ⁇ Y ⁇ 1), LiMn 2-z Ni z O 4 (where, 0 ⁇ z ⁇ 2) and the like), lithium-nickel-cobalt-based oxide (for example, LiNi 1- Y Co Y O 2 (here, 0 ⁇ Y ⁇ 1) and the like, lithium-manganese-cobalt-based oxide (eg, LiCo 1-Y Mn Y O 2 (here, 0 ⁇ Y ⁇ 1), LiMn 2 - z Co z O 4 (here,
  • the lithium transition metal oxide may be doped with tungsten (W) or the like.
  • the positive electrode active material is LiCoO 2 , LiMnO 2 , LiNiO 2 , lithium nickel manganese cobalt oxide (eg, Li (Ni 0.6 Mn 0.2 Co 0.2 ) O 2 , LiNi 0 . 5 Mn 0 . 3 Co 0 . 2 O 2 , or LiNi 0.8 Mn 0.1 Co 0.1 O 2 , or the like, or lithium nickel cobalt aluminum oxide (eg, LiNi 0.8 Co 0.15 Al 0.05 O 2, etc.).
  • the cathode active material may be included in an amount of 70 wt% to 98 wt% based on the total weight of the cathode active material layer. If the content of the positive electrode active material is less than 70% by weight, there is a concern that the capacity is lowered. When the amount of the positive electrode active material is higher than 98% by weight, the relative content of the binder and the conductive material decreases, thereby reducing the adhesion to the positive electrode current collector and the conductivity.
  • the conductive material is the same as described above, it may be included in 1% to 30% by weight relative to the total weight of the positive electrode active material layer.
  • the binder serves to improve adhesion between the cathode active material particles and adhesion between the cathode active material and the current collector.
  • specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC).
  • the binder may be included in an amount of 1% by weight to 30% by weight based on the total weight of the positive electrode active material layer.
  • the positive electrode may be manufactured according to a conventional positive electrode manufacturing method except using the above conductive material.
  • the positive electrode active material and the binder, and optionally a composition for forming a positive electrode active material layer prepared by dispersing or dissolving a conductive material in a solvent are applied onto a positive electrode current collector, followed by drying and rolling;
  • the composition for forming the cathode active material layer may be cast on a separate support, and then the film obtained by peeling from the support may be manufactured by laminating on a cathode current collector.
  • the solvent may be used without particular limitation as long as it is generally used in the art.
  • the solvent may include dimethyl sulfoxide (DMSO), isopropyl alcohol, isomethyl alcohol, N-methylpyrrolidone (NMP), acetone (acetone) or water, etc., any one of these Or mixtures of two or more may be used.
  • the amount of the solvent is sufficient to dissolve or disperse the positive electrode active material, the conductive material, and the binder in consideration of the coating thickness of the slurry and the production yield, and to have a viscosity that can exhibit excellent thickness uniformity during application for the production of the positive electrode. Do.
  • the negative electrode when the electrode is a negative electrode, the negative electrode includes a negative electrode current collector and a negative electrode active material layer positioned on the negative electrode current collector.
  • the negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery.
  • the negative electrode current collector may be formed on a surface of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper, or stainless steel. Surface-treated with carbon, nickel, titanium, silver, and the like, aluminum-cadmium alloy and the like can be used.
  • the negative electrode current collector may have a thickness of 3 ⁇ m to 500 ⁇ m, and like the positive electrode current collector, fine concavities and convexities may be formed on the surface of the current collector to enhance the bonding force of the negative electrode active material.
  • it can be used in various forms, such as a film, a sheet, a foil, a net, a porous body, a foam, a nonwoven body.
  • the negative electrode active material layer may include a negative electrode active material and a conductive material, and optionally a binder.
  • a compound capable of reversible intercalation and deintercalation of lithium may be used.
  • Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fibers, and amorphous carbon;
  • Metallic compounds capable of alloying with lithium such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloys, Sn alloys or Al alloys;
  • Metal oxides capable of doping and undoping lithium such as SiO x (0 ⁇ x ⁇ 2), SnO 2 , vanadium oxide, lithium vanadium oxide;
  • a composite including the metallic compound and the carbonaceous material such as a Si-C composite or a Sn-C composite, and any one or a mixture of two or more thereof may be used.
  • a metal lithium thin film may be used as the anode active material.
  • the carbon material both low crystalline carbon and high crystalline carbon can be used. Soft crystalline carbon and hard carbon are typical low crystalline carbon, and high crystalline carbon is amorphous, plate, scaly, spherical or fibrous natural graphite or artificial graphite, Kish graphite (Kish) graphite, pyrolytic carbon, mesophase pitch based carbon fiber, meso-carbon microbeads, mesophase pitches and petroleum or coal tar pitch High-temperature calcined carbon such as derived cokes is typical.
  • the binder and the conductive material may be the same as described above in the positive electrode.
  • the negative electrode is coated with a negative electrode active material and a conductive material, and optionally a composition for forming a negative electrode prepared by dispersing or dissolving a binder in a solvent, followed by drying;
  • the negative electrode forming composition may be cast on a separate support, and then the film obtained by peeling from the support may be laminated on a negative electrode current collector.
  • the solvent may be the same as described above in the positive electrode.
  • an electrochemical device including the electrode is provided.
  • the electrochemical device may be specifically a battery or a capacitor, and more specifically, may be a lithium secondary battery.
  • the lithium secondary battery may specifically include a positive electrode, a negative electrode positioned to face the positive electrode, a separator and an electrolyte interposed between the positive electrode and the negative electrode, and at least one of the positive electrode and the negative electrode may be the electrode.
  • the lithium secondary battery may further include a battery container for accommodating the electrode assembly of the positive electrode, the negative electrode, and the separator, and a sealing member for sealing the battery container.
  • the separator separates the negative electrode and the positive electrode and provides a movement path of lithium ions, and can be used without particular limitation as long as it is usually used as a separator in a lithium secondary battery. It is preferable that it is resistance and excellent in electrolyte solution moisture-wetting ability.
  • a porous polymer film for example, a porous polymer film made of a polyolefin-based polymer such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer and ethylene / methacrylate copolymer or the like Laminate structures of two or more layers may be used.
  • porous nonwoven fabrics such as nonwoven fabrics made of high melting point glass fibers, polyethylene terephthalate fibers and the like may be used.
  • a coated separator containing a ceramic component or a polymer material may be used to secure heat resistance or mechanical strength, and may be optionally used as a single layer or a multilayer structure.
  • examples of the electrolyte used in the present invention include an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel polymer electrolyte, a solid inorganic electrolyte, a molten inorganic electrolyte, and the like, which can be used in manufacturing a lithium secondary battery. It doesn't happen.
  • the electrolyte may include an organic solvent and a lithium salt.
  • the organic solvent may be used without particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move.
  • the organic solvent may be an ester solvent such as methyl acetate, ethyl acetate, ⁇ -butyrolactone or ⁇ -caprolactone; Ether solvents such as dibutyl ether or tetrahydrofuran; Ketone solvents such as cyclohexanone; Aromatic hydrocarbon solvents such as benzene and fluorobenzene; Dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), propylene carbonate, Carbonate solvents such as PC); Alcohol solvents such as ethyl alcohol and isopropyl alcohol; Nitriles such as R-CN (R is a C2 to C20 linear, branched or cyclic hydrocarbon group, which may include a
  • carbonate-based solvents are preferable, and cyclic carbonates having high ionic conductivity and high dielectric constant (for example, ethylene carbonate or propylene carbonate) that can improve the charge and discharge performance of a battery, and low viscosity linear carbonate compounds (for example, a mixture of ethyl methyl carbonate, dimethyl carbonate or diethyl carbonate and the like is more preferable.
  • the cyclic carbonate and the chain carbonate may be mixed and used in a volume ratio of about 1: 1 to about 1: 9, so that the performance of the electrolyte may be excellent.
  • the lithium salt may be used without particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery.
  • the lithium salt is LiPF 6 , LiClO 4 , LiAsF 6 , LiBF 4 , LiSbF 6 , LiAl0 4 , LiAlCl 4 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , LiN (C 2 F 5 SO 3 ) 2 , LiN (C 2 F 5 SO 2 ) 2 , LiN (CF 3 SO 2 ) 2 .
  • LiCl, LiI or LiB (C 2 O 4 ) 2 and the like can be used.
  • the concentration of the lithium salt is preferably used within the range of 0.1M to 2.0M. When the concentration of the lithium salt is included in the above range, since the electrolyte has an appropriate conductivity and viscosity, it can exhibit excellent electrolyte performance, and lithium ions can move effectively.
  • the electrolyte includes halogenated carbonate-based compounds such as difluoro ethylene carbonate, pyridine, triethyl phosphate, etc., for the purpose of improving battery life characteristics, reducing battery capacity, and improving discharge capacity of the battery.
  • halogenated carbonate-based compounds such as difluoro ethylene carbonate, pyridine, triethyl phosphate, etc.
  • the lithium secondary battery including the electrode manufactured by using the conductive material according to the present invention can stably exhibit excellent discharge capacity, output characteristics, and capacity retention rate by decreasing resistance due to an increase in electrical conductivity in the electrode.
  • portable devices such as a mobile telephone, a notebook computer, a digital camera, and the electric vehicle field
  • HEV hybrid electric vehicle
  • a battery module including the lithium secondary battery as a unit cell and a battery pack including the same are provided.
  • the battery module or the battery pack is a power tool (Power Tool); Electric vehicles including electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); Or it can be used as a power source for any one or more of the system for power storage.
  • Power Tool Electric vehicles including electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); Or it can be used as a power source for any one or more of the system for power storage.
  • Fe (NO 3) 2 ⁇ 9H 2 O 2.391mg, Co (NO 3) 2 ⁇ 6H 2 O 7.341mg, (NH 4) 6 Mo 7 O 24 0.552mg and NH 4 VO 3 A solution in which 0.344 mg was completely dissolved in 15.0 ml of distilled water was prepared.
  • As a support after adding the solution prepared above to 12.5 mg of spherical ⁇ -Al 2 O 3 (pore volume: 0.01 cm 3 / g, BET specific surface area: 4.9 m 2 / g, manufactured by Saint Gobain), 100 ° C Aged by stirring for 15 hours in a constant temperature reactor including a reflux bath.
  • Carbon nanotubes were synthesized in a laboratory scale fluidized bed reactor using the supported catalyst prepared in Preparation Example.
  • the supported catalyst prepared above was mounted at the center of a quartz tube having an inner diameter of 55 mm, and then maintained at a synthesis temperature of 670 ° C. in a nitrogen atmosphere, and maintained at a volume mixing ratio of nitrogen, hydrogen, and ethylene gas.
  • Carbon nanotubes were synthesized by reacting for 2 hours while flowing at the same rate (1: 1: 1 volume ratio) at a rate of 60 sccm per minute.
  • a conductive material was prepared in the same manner as in Example 1, except that it was carried out under the conditions shown in Table 1 below.
  • Carbon nanotubes were prepared by the same method as in Example 1, except that the conditions described in Table 1 were performed.
  • the prepared carbon nanotubes were impregnated in hydrochloric acid solution (4N) and then left at room temperature overnight to remove metal chlorides in the carbon nanotubes. Since the resulting carbon nanotubes were washed with water and dried to prepare a conductive material.
  • Example 1-1 Carbon nanotubes prepared in Example 1-1 and Comparative Example 1-1 were observed using a scanning electron microscope (SEM). The results are shown in FIGS. 1A to 2B, respectively.
  • the carbon nanotubes of Example 1-1 and the carbon nanotubes of Comparative Example 1-1 were secondary structures in which the tubular units having the same level of diameter were tangled.
  • the carbon nanotube unit prepared by the manufacturing method according to the present invention has a longer length and a higher linearity than that of Comparative Example 1-1.
  • the spherical particles of the secondary structure also have a larger particle diameter than that of Comparative Example 1-1 in Example 1-1.
  • the conductive materials prepared in Examples 1-1, 1-2 and Comparative Examples 1-1, 1-2, 1-3, 1-4, and 1-5 were prepared by the following method.
  • the primary structure shape, average particle diameter, average circularity, purity, BET specific surface area, bulk density, true density, secondary structure shape, content of metal impurities, and diameters of the units constituting the carbon nanotubes were respectively measured. The results are shown in Table 2 below.
  • Shape of carbon nanotube, average particle diameter (D 50 ), average circularity The shape of the average particle diameter and secondary structure of the carbon nanotubes were observed using a scanning electron microscope.
  • the average circularity was measured from the observed length ratio of the major axis and minor axis (length ratio of major axis / short axis) in the observed carbon nanotubes.
  • BET specific surface area BELSORP-mino II, manufactured by BEL Japan, was calculated from the amount of nitrogen gas adsorption under liquid nitrogen temperature (77K).
  • Example 1-1 Example 1-2 Comparative Example 1-1 Comparative Example 1-2 Comparative Example 1-3 Comparative Example 1-4 Comparative Example 1-5 Secondary structure shape Entangle Entangle Entangle Entangle Entangle Entangle Entangle Diameter of the unit (nm) 50 80 10 500 50 50 60 Average particle diameter of the secondary structure D 50 ( ⁇ m) 530 620 453 820 730 220 520 Average circularity of secondary structure One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One One
  • the volume resistance of the powder was measured for the carbon nanotubes synthesized in Example 1-1 and Comparative Example 1-1. The results are shown in FIG.
  • the carbon nanotube of Example 1-1 has a volume resistivity of 0.01 ohm ⁇ cm to 0.025 ohm ⁇ cm at a packing density of 0.9 g / cc to 1.5 g / cc, The volume resistivity was lower than that of the carbon nanotubes of Comparative Example 1-1 in the same powder density section.
  • a cathode for a lithium secondary battery and a lithium secondary battery were manufactured using the conductive material prepared in Example 1-1.
  • the positive electrode active material, the conductive material and the PVdF binder are mixed in an N-methylpyrrolidone solvent in a weight ratio of 95: 2.5: 2.5 to prepare a composition for forming a positive electrode (viscosity: 5000 mPa ⁇ s), which is aluminum After applying to the current collector, dried at 130, and then rolled to prepare a positive electrode.
  • a composition for forming a positive electrode viscosity: 5000 mPa ⁇ s
  • the current collector dried at 130, and then rolled to prepare a positive electrode.
  • a negative electrode active material a natural graphite, a carbon black conductive material, and a PVdF binder are mixed in an N-methylpyrrolidone solvent in a weight ratio of 85: 10: 5 to prepare a composition for forming a negative electrode, which is applied to a copper current collector. To prepare a negative electrode.
  • An electrode assembly was manufactured between the positive electrode and the negative electrode prepared as described above through a separator of porous polyethylene, the electrode assembly was placed in a case, and an electrolyte solution was injected into the case to prepare a lithium secondary battery.
  • Example 1-2 Except for using the carbon nanotubes prepared in Example 1-2 as the conductive material for forming the positive electrode was carried out in the same manner as in Example 2-1 to prepare a positive electrode and a lithium secondary battery.
  • Example 3 As shown in Table 3, it was carried out in the same manner as in Example 2-1, except that only 1.3% by weight of the carbon nanotubes prepared in Example 1-1 as the conductive material for forming the anode To prepare a positive electrode and a lithium secondary battery.
  • Example 2-1 Except for using the carbon nanotubes prepared in Comparative Examples 1-1 to 1-5 as the conductive material for forming the anode in the amounts shown in Table 3, respectively, the same method as in Example 2-1 To prepare a positive electrode and a lithium secondary battery, respectively.
  • a positive electrode and a lithium secondary battery were prepared in the same manner as in Example 2-1, except that only 1.7 wt% of carbon black was used as the conductive material for forming the positive electrode.
  • Example 1-1 Example 1-1 (0.7 wt%) CB (0.7 wt%) Example 2-2
  • Example 1-2 Example 1 wt.%) CB (0.7 wt%) Example 3
  • Example 1-1 Comparative Example 2-1 Comparative Example 1-1 (0.7 wt%) CB (0.7 wt%) Comparative Example 2-2 Comparative Example 1-2 (0.7 wt.%) CB (0.7 wt%) Comparative Example 2-3
  • Comparative Example 1-3 Comparative 1-3 (0.7 wt.%) CB (0.7 wt%) Comparative Example 2-4
  • Example 1-4 Comparative Example 1-5 (0.7 wt%) CB (0.7 wt%) Comparative Example 3 - CB (1.7 wt%)
  • the lithium secondary batteries prepared in Examples 2-1, 2-2 and 3, Comparative Examples 2-1 to 2-5, and Comparative Example 3 were 2.8 V to room temperature (25 ° C.). Capacity change during charging and discharging within the 4.3 V drive voltage range under the conditions shown in Table 4 below, and capacity change during charging and discharging under the conditions of 1 C / 1C within the 2.8 V to 4.3 V driving voltage range at room temperature (25 ° C.). The voltage drop accordingly was measured and shown in Table 4 and FIGS. 4 and 5.
  • Example 2-1 100 99.6 97.5 88.1 40.0
  • Example 2-2 100 99.6 97.5 87.1 39.1
  • Example 3 100 99.5 95.5 89.0 41.0 Comparative Example 2-1 100 99.5 97.2 83.3 34.5
  • Example 2-1, 2-2 and Example 3 containing the carbon nanotubes prepared in Examples 1-1 or 1-2 as a conductive material were compared using conventional catalysts.
  • Example 2-1 When the charge and discharge of the lithium secondary battery in Example 2-1, Comparative Example 2-1, and Comparative Example 3 at a low temperature (-20 °C) at a temperature of 0.2C within the range of 2.7V to 3.8V drive voltage, The discharge characteristic was evaluated. The results are shown in Table 5 and FIG. 6.
  • Example 2-1 including the carbon nanotubes prepared in Example 1-1 as the conductive material exhibited improved low-temperature discharge characteristics compared to Comparative Example 2-1 and Comparative Example 3.

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Abstract

La présente invention concerne un matériau conducteur pour une batterie secondaire, et une batterie secondaire le contenant, le matériau conducteur comprenant un nanotube de carbone, ayant une structure secondaire dans laquelle sont enchevêtrées des unités de nanotube de carbone ayant un diamètre de 20 à 150 nm, ayant un rapport de masse volumique absolue à masse volumique apparente (TD/BD) de 30 à 120, ayant une teneur en métal inférieure ou égale à 50 ppm, et ayant à la fois une excellente dispersibilité et une pureté élevée, étant ainsi capable d'améliorer, par augmentation de la conductivité à l'intérieur d'une électrode, les performances de la batterie, en particulier, les performances de la batterie à température ambiante et à basse température lorsqu'il est appliqué sur une batterie.
PCT/KR2016/010173 2015-09-10 2016-09-09 Matériau conducteur pour batterie secondaire, et batterie secondaire le contenant WO2017043919A1 (fr)

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EP16844735.7A EP3349280B1 (fr) 2015-09-10 2016-09-09 Matériau conducteur pour batterie secondaire, et batterie secondaire le contenant
CN201680034406.9A CN107735890B (zh) 2015-09-10 2016-09-09 用于二次电池的导电材料以及包含该导电材料的二次电池
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