WO2008088180A1 - Cathode active material and secondary battery comprising the same - Google Patents

Cathode active material and secondary battery comprising the same Download PDF

Info

Publication number
WO2008088180A1
WO2008088180A1 PCT/KR2008/000305 KR2008000305W WO2008088180A1 WO 2008088180 A1 WO2008088180 A1 WO 2008088180A1 KR 2008000305 W KR2008000305 W KR 2008000305W WO 2008088180 A1 WO2008088180 A1 WO 2008088180A1
Authority
WO
WIPO (PCT)
Prior art keywords
lithium
composite oxide
metal composite
containing metal
active material
Prior art date
Application number
PCT/KR2008/000305
Other languages
French (fr)
Inventor
Pil-Kyu Park
Young-Sun Park
Jae-Won Lee
Original Assignee
Lg Chem, Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lg Chem, Ltd. filed Critical Lg Chem, Ltd.
Priority to CN200880002550.XA priority Critical patent/CN101595582B/en
Priority to US12/523,392 priority patent/US8084159B2/en
Priority to EP08704841.9A priority patent/EP2108203B1/en
Priority to JP2009546325A priority patent/JP5474563B2/en
Publication of WO2008088180A1 publication Critical patent/WO2008088180A1/en
Priority to US13/303,450 priority patent/US8304111B2/en

Links

Classifications

    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • 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
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • 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 cathode active material and a secondary battery comprising the same, which can suppress the temporary flow of a large amount of electrons and lithium ions during an internal short, thereby improving safety.
  • lithium secondary battery materials allowing intercalation and deintercalation of lithium ions are used as an anode and a cathode, and organic electrolyte or polymer electrolyte is charged between the cathode and the anode. Also, when lithium ions are intercalated and deintercalated at the cathode and the anode, oxidation/reduction reactions generate electrical energy.
  • the present inventors found that when an entire surface of a first lithium-containing metal composite oxide is coated with a second lithium-containing metal composite oxide having a higher resistance and a lower potential vs. lithium potential than the first lithium- containing metal composite oxide, during an internal short, it is possible to slow down the moving rate of a large amount of lithium ions and electrons from an anode to a cathode, and thus to prevent heat generation caused by the temporary occurrence of over-current, and to improve safety of a battery. Accordingly, the surface of the first cathode active material is stabilized, and thus it is possible to increase the temperature where the first cathode active material is decomposed. Also, since the first cathode active material is not in contact with electrolyte, the side reactions are inhibited, and the ignition temperature is increased. Therefore, it is possible to improve thermal stability of a battery.
  • a cathode active material comprising (a) a first lithium-containing metal composite oxide and (b) a second lithium-containing metal composite oxide coated on an entire particle surface of the first lithium-containing metal composite oxide, the second lithium-containing metal composite oxide having a higher resistance and a lower potential vs. lithium potential (Li/Li + ) than the first lithium-containing metal composite oxide.
  • a secondary battery comprising a cathode, an anode, electrolyte, and a separator, the cathode comprising the cathode active material.
  • the present invention is characterized by a first lithium-containing metal composite oxide of which the entire surface is coated with a second lithium-containing metal composite oxide, wherein the second lithium-containing metal composite oxide has a lower potential vs. lithium potential (Li/Li + ) and a higher resistance than the first lithium- containing metal composite oxide.
  • a first lithium-containing metal composite oxide at a discharge rate of less than 5C, a first lithium-containing metal composite oxide, the entire surface of which is coated with a second lithium-containing metal composite oxide of a high resistance value, shows a similar discharge graph to an uncoated first lithium-containing metal composite oxide (see FIGs. 4 and 5).
  • the coated firsb lithium-containing metal composite oxide shows a different discharge graph from the uncoated first lithium-containing metal composite oxide (see
  • FIGs. 6-8 At a discharge rate of less than
  • a second lithium-containing metal composite oxide having a high resistance value does not act as a significant internal resistance, and on the other hand, at a discharge rate of more than 5C, when the first lithium-containing metal composite oxide is discharged, the second lithium-containing metal composite oxide having a high resistance value acts as a significant internal resistance.
  • lithium ions are intercalated in a cathode active material, and herein, the cathode active material is reduced by receiving electrons. Also, during a discharge process including an internal short, a potential of a cathode is decreased, and lithium ions (Li + ) and electrons are firstly intercalated in a first lithium- containing metal composite oxide having a higher potential than a second lithium-containing metal composite oxide. In the present invention, an entire surface of a first lithium-containing metal composite oxide is coated with a second lithium-containing metal composite oxide having a lower potential vs. lithium potential and a higher resistance than the first lithium-containing metal composite oxide.
  • the second lithium-containing metal composite oxide acts as a significant electric resistance layer, and suppresses the inflow of electrons into the core of the first lithium- containing metal composite oxide having a high potential vs. lithium potential, thereby inhibiting the intercalation of lithium ions.
  • lithium ions and electrons may be intercalated in the first lithium-containing metal composite oxide through the uncoated surface. Accordingly, it is impossible to slow down the intercalation rate of lithium ions and electrons. Also, since a narrow surface, through which lithium ions and electrons pass, causes a nozzle effect, a moving rate of lithium ions and electrons is increased. Therefore, heat is locally generated, and thus may reduce the safety of a battery (see FIG. 3) . Conventionally, in order to adjust a discharge potential of a cathode within a certain range, an electrode in which cathode active materials of different potentials vs.
  • lithium potential Li/Li +
  • Li/Li + lithium potential
  • a cathode active material according to the present invention includes a second lithium-containing metal composite oxide capable of intercalating and deintercalating lithium. Accordingly, there are very few problems of performance degradation of a battery (such as, degradation of capacity, a lifetime property, etc.) which has been conventionally caused by an electrode additive not concerned in the electrochemical reactions in a battery.
  • first lithium-containing metal composite oxide having a high potential vs. lithium potential and a second lithium-containing metal composite oxide having a relatively low potential vs. lithium potential, are used as a large amount of core material and a small amount of coating material, respectively, the first lithium-containing metal composite oxide having a high drive voltage and high energy density can act as a main cathode active material.
  • a cathode active material includes a much smaller amount of second lithium-containing metal composite oxide than a different cathode active material in which a first lithium-containing metal composite oxide and a second lithium-containing metal composite oxide are simply mixed with each other, it is possible to achieve the same or an even higher level of improved safety as the different cathode active material. Accordingly, it is possible to reduce the degradation of electrochemical properties, which may be caused by an excessive amount of a second lithium-containing metal composite oxide.
  • the surface of a first lithium-containing metal composite oxide is completely covered with a second lithium-containing metal composite oxide. Accordingly, the surface energy of the first lithium-containing metal composite oxide is lowered and stabilized, and thus it is possible to increase a exothermic temperature where the first lithium- containing metal composite oxide is decomposed and generates oxygen. Also, it is possible to improve thermal stability by inhibiting side reactions of the first lithium-containing metal composite oxide and electrolyte.
  • the range of a potential difference vs. lithium potential between the first lithium-containing metal composite oxide and the second lithium-containing metal composite oxide is not particularly limited.
  • the first lithium- containing metal composite oxide preferably has a potential of 3.7 V or more (Li/Li + ) in such a manner that oxidation/reduction reactions of the first lithium-containing metal composite oxide can be performed at a relatively high potential.
  • the second lithium-containing metal composite oxide preferably has a potential vs. lithium potential of less than 3.7 V (Li/Li + ) , which is relatively lower than that of the first lithium-containing metal composite oxide.
  • lithium potential (Li/Li + , ⁇ P) between the first lithium-containing metal composite oxide and the second lithium-containing metal composite oxide is within a range of 0.3 V ⁇ ⁇ p ⁇ 5 V, and more preferably within a range of 0.3V ⁇ p ⁇ 3.5V, but is not limited to this range .
  • An electric resistance of an object varies according to the shape, the size, and the way of current flow (even in the case of objects using the same material) .
  • the resistivity is expressed in ⁇ » m (as an MKSA unit) .
  • the second lithium-containing metal composite oxide may not function as an internal electric resistance layer during a normal discharge, but may function as an internal electric resistance layer during a high-rate discharge more than a certain value (for example, 5C) .
  • a certain value for example, 5C
  • the coated thickness (L) and the specific surface area (S) are thicker and smaller, respectively, the second lithium-containing metal composite oxide has a higher resistance value (R 2 ) .
  • the specific surface area is adjusted by adjusting the size of the second lithium- containing metal composite oxide.
  • the range of a current rate, in which a coated layer of the second lithium-containing metal composite oxide acts as a significant electric resistance layer is not limited as long as the current is out of the range of a normal battery operation.
  • the range may be 5C or more.
  • a resistance difference between a first lithium-containing metal composite oxide and a second lithium- containing metal composite oxide may be represented in the electrical conductivity ratio of the second lithium-containing metal composite oxide to the first lithium-containing metal composite oxide.
  • the electrical conductivity ratio preferably has a range of 10 ⁇ x ⁇ 10 ⁇ 7 , and more preferably has a range of 10 "1 ⁇ 10 ⁇ 3 , but is not limited to this.
  • the second lithium-containing metal composite oxide coated on the first lithium-containing metal composite oxide inevitably acts as a resistance. Also, when the electrical conductivity ratio of the second lithium-containing metal composite oxide to the first lithium-containing metal composite oxide is less than the above described range, (that is, the resistance difference is large) , it is possible to coat the surface of the second lithium-containing metal composite oxide with a conductive material (for example, a carbonaceous material, etc.) in order to adjust the ratio to the above described range.
  • a conductive material for example, a carbonaceous material, etc.
  • a reversible compound capable of intercalating and deintercalat ing lithium which has a potential difference and a resistance ratio as described above, thereby improving the safety of a battery, may be used in the present invention.
  • the cathode active material according to the present invention it is preferable that particles of a second lithium-containing metal composite oxide having a relatively low potential vs. lithium potential and a high resistance are covered on the entire surface of a first lithium-containing metal composite oxide (see FIG. 1) .
  • the surface area, size, and usage rate of a first lithium-containing metal composite oxide and a second lithium-containing metal composite oxide are required to be adjusted.
  • a cathode according to the present invention will be obtained by adjusting the surface area, size, and usage rate of a second lithium-containing metal composite oxide.
  • a second lithium-containing metal composite oxide (particle size: 5 ⁇ m) is required to be used in an amount of about 20 wt% .
  • a particle size of a second lithium-containing metal composite oxide is 2.5 ⁇ m
  • the first lithium- containing metal composite oxide may be completely coated with an amount of 7.5 wt% of the second lithium-containing metal composite oxide.
  • the surface area, particle size, and usage rate of the second lithium-containing metal composite oxide may be appropriately adjusted within a conventional range known to one skilled in the art.
  • the weight ratio of the first lithium-containing metal composite oxide to the second lithium-containing metal composite oxide is preferably within the range of 70:30 ⁇ 97.5:2.5, but is not limited to this. When the weight ratio is less than the above range, electrochemical performance may be reduced. On the other hand, when the weight ratio is more than the above range, the second lithium-containing metal composite oxide cannot sufficiently act as a resistance, and thus the safety of a battery cannot be improved.
  • the first lithium-containing metal composite oxide has a particle size within the range of 5/zm ⁇ 30 ⁇ m
  • the second lithium-containing metal composite oxide has a particle size within the range of 30 nm ⁇ 5 ⁇ m.
  • the first lithium-containing metal composite oxide has a specific surface area within the range of 0.01 ⁇ 0.2 m 2 /g
  • the second lithium-containing metal composite oxide has a specific surface area within the range of 0.5 ⁇ 30 m 2 /g.
  • the particle size and the specific area are not limited to the above described ranges.
  • the particle size may be within the range of 10-20 IM 1 the electrical conductivity may be about 10 ⁇ 2 S/cm, and the specific surface area may be about 0.2 m 2 /g.
  • LiMnO 4 Li (Nii /3 Mni /3 C ⁇ i / 3) O 2 , LiFePO 4 , etc. may be used.
  • the particle size may be within the range of 0.5 ⁇ 5 ⁇ m
  • the electrical conductivity may be about 10 ⁇ 4 ⁇ 10 "9 S/cm
  • the specific surface area may be about 0.5 ⁇ 13 m 2 /g.
  • the conductivity may be increased up to the range of 10 ⁇ 2 ⁇ 10 ⁇ 3 .
  • Non-limiting examples of a method of obtaining a cathode active material according to the present invention include jet mill, spray drying, etc.
  • a Mechanofusion method may be used, and also, a NOBILTATM (Hosokawa Micron Corporation) , which has better milling power than the Mechanofusion method, may be used.
  • Such a coated particle is obtained by the steps of: fixing both kinds of powder on the inner wall of a rotative container by a centrifugal force; momentarily compacting the powder by an inner member fixed to a center shaft; scraping the powder with a scraper at a high speed; complexing the particles through repeated compacting/scraping (shearing) operation and heat-adhering both kinds of powder by a mechanofusion operation.
  • this example is illustrative only, and the scope of the present invention is not limited thereto.
  • particle hardness of the second lithium-containing metal composite oxide may be lower than that of the first lithium-containing metal composite oxide because, in the process of coating the second lithium- containing metal composite oxide on the surface of the first lithium-containing metal composite oxide by milling the two materials, the second lithium-containing metal composite oxide has to be finely ground so as to be uniformly coated on the surface of the first lithium-containing metal composite oxide.
  • the first lithium-containing metal composite oxide does not have to be ground.
  • the secondary battery is a lithium secondary battery
  • the lithium secondary battery include a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, a lithium ion polymer secondary battery, etc.
  • the electrolyte for the battery includes conventional electrolyte components known to one skilled in the art, that is, electrolyte salts and an organic solvent.
  • An electrolyte salt that may be used in the present invention includes a salt represented by the formula of A + B " , wherein A + represents an alkali metal cation selected from the group including Li + , Na + , K + and combinations thereof, and B- represents an anion selected from the group including PF ⁇ ⁇ , BF4 “ , Cl “ , Br “ , I “ , ClO 4 “ , AsF 6 “ , CH 3 CO 2 " , CF 3 SO 3 " , N (CF 3 SO 2 ) 2 ⁇ , C (CF 2 SO 2 ) 3 ⁇ and combinations thereof.
  • a lithium salt is particularly preferred.
  • organic solvent a conventional solvent known to one skilled in the art, that is, cyclic carbonate and/or linear carbonate, may be used, and non-limiting examples of such carbonate include propylene carbonate (PC) , ethylene carbonate (EC) , diethyl carbonate (DEC) , dimethyl carbonate (DMC) , dipropyl carbonate (DPC) , dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP) , ethyl methyl carbonate (EMC) , gamma-butyrolactone (GBL) , fluoroethylene carbonate (FEC), methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, pentyl acetate, methyl propionate, ethyl
  • separator there is no particular limitation in the separator that may be used in the present invention, as long as the separator is a porous material.
  • Non-limiting examples of the separator that may be used include a polypropylene-based, polyethylene- based, polyolefin-based porous separator. Porous separators to which inorganic materials are added may also be used.
  • the secondary battery may be a cylindrical battery using a can, a prismatic battery, a pouch-type battery or a coin-type battery.
  • FIG. 1 is a scanning electron microscopy (SEM) picture of an active material LiCoC> 2 surface-coated with LiFePO 4 , which is prepared by Example 1;
  • FIG. 2 is a SEM picture of an active material LiCoO 2 simply mixed with LiFePO 4 , which is prepared by Comparative Example 2;
  • FIG. 3 is a schematic drawing illustrating active materials according to Examples and Comparative Examples;
  • FIGs. 4 ⁇ 8 illustrate DC impedance values of an active material LiCoO 2 surface-coated with LiFePO 4 , which is prepared by Example 4, and DC impedance values of an active material LiCoO 2 , which is prepared by Comparative Example 1.
  • FIG. 4, FIG. 5, FIG. 6, FIG. 7 and FIG. 8 illustrate the values at the current rates of 1C, 5C, 1OC, 2OC, and 3OC, respectively.
  • FIG. 9 is a SEM picture of an active material LiCoO 2 surface-coated with LiFePO 4 , which is prepared by Example 5.
  • FIG. 1 shows a scanning electron microscopy (SEM) picture of the obtained powder.
  • SEM scanning electron microscopy
  • fine particles of LiFePO 4 are uniformly coated on the surface of LiCoO 2 particles .
  • the coated cathode active material together with a conductive material and a binding agent, was added in a solvent NMP (N-methyl-2-pyrrolidone) , to obtain cathode slurry. Then, a cathode was obtained by coating the cathode slurry on Al current collector.
  • NMP N-methyl-2-pyrrolidone
  • anode active material a graphite material was used as an anode active material.
  • a binding agent was added in NMP to obtain anode slurry.
  • an anode was obtained by coating the anode slurry on Cu current collector.
  • electrolyte As electrolyte, EC/EMC (ethyl carbonate/ethyl methyl carbonate, volumetric ratio 1:2) solution containing IM LiPF ⁇ dissolved therein was used. A polyolefin-based separator was inserted between the obtained cathode and anode, and then the electrolyte was charged to obtain a battery.
  • EMC ethyl carbonate/ethyl methyl carbonate, volumetric ratio 1:2
  • a cathode active material and a battery were obtained in the same manner as described in Example 1, except that LiCoO 2 and LiFePO 4 were mixed in a weight ratio of 95: 5 instead of 97.5: 2.5.
  • Example 3 A cathode active material and a battery were obtained in the same manner as described in Example 1, except that LiCoO 2 and LiFePO 4 were mixed in a weight ratio of 90: 10 instead of 97.5: 2.5. [Example 4]
  • a cathode active material and a battery were obtained in the same manner as described in Example 1, except that LiCo ⁇ 2 and LiFeP0 4 were mixed in a weight ratio of 85: 15 instead of 97.5: 2.5.
  • a cathode active material and a battery were obtained in the same manner as described in Example 1, except that a NOBILTATM (Hosokawa Micron Corporation) was performed instead of a mechanofusion method.
  • NOBILTATM Hosokawa Micron Corporation
  • Example 1 A cathode active material and a battery were obtained in the same manner as described in Example 1, except that LiCoO 2 was used alone as a cathode active material.
  • the thermal stability of a battery was determined by using Differential Scanning Calorimetry (DSC) , and the performance of a battery was determined by manufacturing a coin half cell.
  • DSC Differential Scanning Calorimetry

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

Disclosed are a cathode active material and a secondary battery including the same. Herein, the cathode active material includes (a) a first lithium-containing metal composite oxide and (b) a second lithium-containing metal composite oxide coated on an entire particle surface of the first lithium-containing metal composite oxide, the second lithium-containing metal composite oxide having a higher resistance and a lower potential vs. lithium potential (Li/Li'1) than the first lithium-containing metal composite oxide. In the disclosed cathode active material, an entire surface of a first lithium-containing metal composite oxide is coated with a second lithium-containing metal composite oxide having a high resistance value and a low potential vs. lithium potential. Therefore, during an internal short of a secondary battery, it is possible to slow down the moving rate of a large amount of lithium ions and electrons from an anode to a cathode, and thus to prevent heat generation caused by the occurrence of temporary over-current. Also, it is possible to increase the temperature where a cathode active material is decomposed and gas is generated, and to improve thermal stability by inhibiting side reactions of the cathode active material and electrolyte.

Description

CATHODE ACTIVE MATERIAL AND SECONDARY BATTERY COMPRISING THE
SAME
Technical Field The present invention relates to a cathode active material and a secondary battery comprising the same, which can suppress the temporary flow of a large amount of electrons and lithium ions during an internal short, thereby improving safety.
Background Art
Recently, as electronic devices have been miniaturized, and lightened, and portable electronic devices have been widely used, research on a lithium secondary battery of high energy density has been actively performed. In a lithium secondary battery, materials allowing intercalation and deintercalation of lithium ions are used as an anode and a cathode, and organic electrolyte or polymer electrolyte is charged between the cathode and the anode. Also, when lithium ions are intercalated and deintercalated at the cathode and the anode, oxidation/reduction reactions generate electrical energy.
In a lithium secondary battery, a lithium-containing metal composite oxide having a high potential vs. lithium potential (Li/Li+) (for example, LiCoO2) has been mainly used as a cathode active material, and a carbonaceous material has been mainly used as an anode active material. Such materials enable the lithium secondary battery to have high capacity and high power. However, when the above described cathode active material having a high potential vs. lithium potential (Li/Li+) is used alone, electrons and lithium ions suddenly move from an anode to a cathode during an internal short caused by internal/external conditions. Accordingly, a large amount of current temporarily flows, and thus heat is suddenly generated within the battery, thereby causing fire or explosion of the battery.
In addition, when the cathode active material is exposed at a high temperature atmosphere or a battery temperature is increased by an abnormal operation of a battery, the cathode active material is decomposed at temperatures higher than a certain temperature, and thus generates oxygen. Accordingly, fire or explosion may occur in the battery. Also, when side reactions occur by contacting the cathode active material with nonaqueous electrolyte, an exothermic reaction may cause an explosion. Especially, when gas is generated within the battery due to the side reactions, the possibility of battery explosion is increased.
Disclosure of the Invention
Therefore, the present inventors found that when an entire surface of a first lithium-containing metal composite oxide is coated with a second lithium-containing metal composite oxide having a higher resistance and a lower potential vs. lithium potential than the first lithium- containing metal composite oxide, during an internal short, it is possible to slow down the moving rate of a large amount of lithium ions and electrons from an anode to a cathode, and thus to prevent heat generation caused by the temporary occurrence of over-current, and to improve safety of a battery. Accordingly, the surface of the first cathode active material is stabilized, and thus it is possible to increase the temperature where the first cathode active material is decomposed. Also, since the first cathode active material is not in contact with electrolyte, the side reactions are inhibited, and the ignition temperature is increased. Therefore, it is possible to improve thermal stability of a battery.
According to an aspect of the present invention, there is provided a cathode active material comprising (a) a first lithium-containing metal composite oxide and (b) a second lithium-containing metal composite oxide coated on an entire particle surface of the first lithium-containing metal composite oxide, the second lithium-containing metal composite oxide having a higher resistance and a lower potential vs. lithium potential (Li/Li+) than the first lithium-containing metal composite oxide.
According to another aspect of the present invention, there is provided a secondary battery comprising a cathode, an anode, electrolyte, and a separator, the cathode comprising the cathode active material.
Reference will now be made in detail to the exemplary embodiments of the present invention.
The present invention is characterized by a first lithium-containing metal composite oxide of which the entire surface is coated with a second lithium-containing metal composite oxide, wherein the second lithium-containing metal composite oxide has a lower potential vs. lithium potential (Li/Li+) and a higher resistance than the first lithium- containing metal composite oxide. According to experimental examples, at a discharge rate of less than 5C, a first lithium-containing metal composite oxide, the entire surface of which is coated with a second lithium-containing metal composite oxide of a high resistance value, shows a similar discharge graph to an uncoated first lithium-containing metal composite oxide (see FIGs. 4 and 5). On the other hand, when the current rate is suddenly increased up to more than 5C, the coated firsb lithium-containing metal composite oxide shows a different discharge graph from the uncoated first lithium-containing metal composite oxide (see
FIGs. 6-8). In other words, at a discharge rate of less than
5C, when a first lithium-containing metal composite oxide
(which is firstly reduced due to a high potential vs. lithium potential Li/Li+) is discharged, a second lithium-containing metal composite oxide having a high resistance value does not act as a significant internal resistance, and on the other hand, at a discharge rate of more than 5C, when the first lithium-containing metal composite oxide is discharged, the second lithium-containing metal composite oxide having a high resistance value acts as a significant internal resistance.
During a discharge process, lithium ions are intercalated in a cathode active material, and herein, the cathode active material is reduced by receiving electrons. Also, during a discharge process including an internal short, a potential of a cathode is decreased, and lithium ions (Li+) and electrons are firstly intercalated in a first lithium- containing metal composite oxide having a higher potential than a second lithium-containing metal composite oxide. In the present invention, an entire surface of a first lithium-containing metal composite oxide is coated with a second lithium-containing metal composite oxide having a lower potential vs. lithium potential and a higher resistance than the first lithium-containing metal composite oxide. Therefore, during a high-rate discharge, such as an internal short, the second lithium-containing metal composite oxide acts as a significant electric resistance layer, and suppresses the inflow of electrons into the core of the first lithium- containing metal composite oxide having a high potential vs. lithium potential, thereby inhibiting the intercalation of lithium ions. In other words, during an internal short, it is possible to slow down the intercalation rate of a large amount of lithium ions and electrons from an anode to a cathode, and thus to prevent heat generation caused by the temporary occurrence of over-current, thereby improving the safety of a battery.
If only a part of the surface of a first lithium- containing metal composite oxide is coated with the second lithium-containing metal composite oxide, lithium ions and electrons may be intercalated in the first lithium-containing metal composite oxide through the uncoated surface. Accordingly, it is impossible to slow down the intercalation rate of lithium ions and electrons. Also, since a narrow surface, through which lithium ions and electrons pass, causes a nozzle effect, a moving rate of lithium ions and electrons is increased. Therefore, heat is locally generated, and thus may reduce the safety of a battery (see FIG. 3) . Conventionally, in order to adjust a discharge potential of a cathode within a certain range, an electrode in which cathode active materials of different potentials vs. lithium potential (Li/Li+) are included has been used as a cathode for a lithium secondary battery. However, when an internal short occurs, for the same reason described above, there has been a problem in that fire or explosion of a battery may suddenly occur.
Meanwhile, in the present invention, since the surface of a first lithium-containing metal composite oxide is uniformly coated with a second lithium-containing metal composite oxide of a high potential difference and a high resistance, it is possible to maximize a resistance function and thus to suppress the flow of lithium ions when over- current flows . Contrary to an electrochemically irreversible electrode additive, which has been conventionally used for a specific effect, a cathode active material according to the present invention includes a second lithium-containing metal composite oxide capable of intercalating and deintercalating lithium. Accordingly, there are very few problems of performance degradation of a battery (such as, degradation of capacity, a lifetime property, etc.) which has been conventionally caused by an electrode additive not concerned in the electrochemical reactions in a battery. In addition, since a first lithium- containing metal composite oxide having a high potential vs. lithium potential, and a second lithium-containing metal composite oxide having a relatively low potential vs. lithium potential, are used as a large amount of core material and a small amount of coating material, respectively, the first lithium-containing metal composite oxide having a high drive voltage and high energy density can act as a main cathode active material. Also, in the present invention, although a cathode active material includes a much smaller amount of second lithium-containing metal composite oxide than a different cathode active material in which a first lithium-containing metal composite oxide and a second lithium-containing metal composite oxide are simply mixed with each other, it is possible to achieve the same or an even higher level of improved safety as the different cathode active material. Accordingly, it is possible to reduce the degradation of electrochemical properties, which may be caused by an excessive amount of a second lithium-containing metal composite oxide.
Also, in the cathode active material according to the present invention, the surface of a first lithium-containing metal composite oxide is completely covered with a second lithium-containing metal composite oxide. Accordingly, the surface energy of the first lithium-containing metal composite oxide is lowered and stabilized, and thus it is possible to increase a exothermic temperature where the first lithium- containing metal composite oxide is decomposed and generates oxygen. Also, it is possible to improve thermal stability by inhibiting side reactions of the first lithium-containing metal composite oxide and electrolyte. The range of a potential difference vs. lithium potential between the first lithium-containing metal composite oxide and the second lithium-containing metal composite oxide is not particularly limited. However, the first lithium- containing metal composite oxide preferably has a potential of 3.7 V or more (Li/Li+) in such a manner that oxidation/reduction reactions of the first lithium-containing metal composite oxide can be performed at a relatively high potential. Also, the second lithium-containing metal composite oxide preferably has a potential vs. lithium potential of less than 3.7 V (Li/Li+) , which is relatively lower than that of the first lithium-containing metal composite oxide. Herein, the range of a potential difference vs. lithium potential (Li/Li+, ΔP) between the first lithium-containing metal composite oxide and the second lithium-containing metal composite oxide is within a range of 0.3 V < Λp < 5 V, and more preferably within a range of 0.3V<Δp < 3.5V, but is not limited to this range .
An electric resistance of an object varies according to the shape, the size, and the way of current flow (even in the case of objects using the same material) . For example, when the constant current flows between a couple of opposite surfaces of a Im3 cube, V is represented by V= p» I according to Ohm's law (herein, V represents the voltage between the surfaces, I represents the current, and p represents the resistivity) . The resistivity is expressed in Ω»m (as an MKSA unit) . When an object has a cross sectional area of Sm2, and a length of Lm, the resistance R is represented by R= p» L / S. In the present invention, it is possible to adjust the resistance value (R2) of a second lithium-containing metal composite oxide, by adjusting a coated thickness (L) and a specific surface area (S) of the second lithium-containing metal composite oxide. Accordingly, the second lithium- containing metal composite oxide may not function as an internal electric resistance layer during a normal discharge, but may function as an internal electric resistance layer during a high-rate discharge more than a certain value (for example, 5C) . For example, as the coated thickness (L) and the specific surface area (S) are thicker and smaller, respectively, the second lithium-containing metal composite oxide has a higher resistance value (R2) . The specific surface area is adjusted by adjusting the size of the second lithium- containing metal composite oxide. When the resistance value (R2) of the second lithium- containing metal composite oxide is increased, the current value (I) passing through the coated layer of the second lithium-containing metal composite oxide is decreased because of V=IR (V: voltage, I: current, and R: resistance). Therefore, when heating value (Q/t=VI, Q= heating value, t=time) per unit time (t) is decreased in the core particle of a first lithium-containing metal composite oxide, the safety of a battery can be improved.
The range of a current rate, in which a coated layer of the second lithium-containing metal composite oxide acts as a significant electric resistance layer, is not limited as long as the current is out of the range of a normal battery operation. For example, the range may be 5C or more.
Further, a resistance difference between a first lithium-containing metal composite oxide and a second lithium- containing metal composite oxide may be represented in the electrical conductivity ratio of the second lithium-containing metal composite oxide to the first lithium-containing metal composite oxide. Herein, the electrical conductivity ratio preferably has a range of 10~x ~ 10~7, and more preferably has a range of 10"1 ~ 10~3, but is not limited to this. When the resistance difference between the two materials has a large value, the battery safety is improved, but the battery performance may be reduced, and on the other hand, when the resistance difference has a small value, it is difficult to achieve a desired effect of the present invention. Since during an internal short (that is, discharge) , lithium ions prefer to be intercalated in the first lithium-containing metal composite oxide having higher potential, the second lithium-containing metal composite oxide coated on the first lithium-containing metal composite oxide inevitably acts as a resistance. Also, when the electrical conductivity ratio of the second lithium-containing metal composite oxide to the first lithium-containing metal composite oxide is less than the above described range, (that is, the resistance difference is large) , it is possible to coat the surface of the second lithium-containing metal composite oxide with a conductive material (for example, a carbonaceous material, etc.) in order to adjust the ratio to the above described range.
Non-limiting examples of the first lithium-containing metal composite oxide that may be used in the present invention include LiMO2(M = Co, Mn, Ni, Nii/3Cθi/3Mni/3, Cr, V), LiMO4(M = CoMn, NiV, CoV, CoP, MnP, NiP, Mn2) and a mixture of the materials, and non-limiting examples of the second lithium-containing metal composite oxide include LiMO4(M = V2, FeP), LiMO2(M = Mn, Mo, W), LiV6Oi3, LiTiS2, LiWO2 and a mixture of the materials. In addition, a reversible compound capable of intercalating and deintercalat ing lithium, which has a potential difference and a resistance ratio as described above, thereby improving the safety of a battery, may be used in the present invention.
In the cathode active material according to the present invention, it is preferable that particles of a second lithium-containing metal composite oxide having a relatively low potential vs. lithium potential and a high resistance are covered on the entire surface of a first lithium-containing metal composite oxide (see FIG. 1) . In order to obtain such a cathode active material, the surface area, size, and usage rate of a first lithium-containing metal composite oxide and a second lithium-containing metal composite oxide are required to be adjusted. A cathode according to the present invention will be obtained by adjusting the surface area, size, and usage rate of a second lithium-containing metal composite oxide. For example, in order to coat a first lithium-containing metal composite oxide particle having a particle size of 20//m, a second lithium-containing metal composite oxide (particle size: 5μm) is required to be used in an amount of about 20 wt% . On the other hand, when a particle size of a second lithium- containing metal composite oxide is 2.5μm, the first lithium- containing metal composite oxide may be completely coated with an amount of 7.5 wt% of the second lithium-containing metal composite oxide.
Therefore, in the present invention, in order to obtain a cathode active material having a coated surface as described above, the surface area, particle size, and usage rate of the second lithium-containing metal composite oxide may be appropriately adjusted within a conventional range known to one skilled in the art. Herein, the weight ratio of the first lithium-containing metal composite oxide to the second lithium-containing metal composite oxide is preferably within the range of 70:30 ~ 97.5:2.5, but is not limited to this. When the weight ratio is less than the above range, electrochemical performance may be reduced. On the other hand, when the weight ratio is more than the above range, the second lithium-containing metal composite oxide cannot sufficiently act as a resistance, and thus the safety of a battery cannot be improved.
However, when there is a large difference between specific surface areas of the first lithium-containing metal composite oxide and the second lithium-containing metal composite oxide, it is possible to achieve the same effect as that of the above described range although the weight ratio is smaller than that of the range. Also, contrary to simply blended two active materials in which the weight ratio is required to be increased due to unmixed and conglomerated particles, when the surface of either particle is coated with another material as in the present invention, it is possible to achieve the same effect as that of the above described range although the weight ratio is smaller than that of the range.
As described above, in order to coat the surface of a first lithium-containing metal composite oxide with a second lithium-containing metal composite oxide, it is preferable that the first lithium-containing metal composite oxide has a particle size within the range of 5/zm ~ 30 μm, and the second lithium-containing metal composite oxide has a particle size within the range of 30 nm ~ 5 βm. Also, it is preferable that the first lithium-containing metal composite oxide has a specific surface area within the range of 0.01 ~ 0.2 m2/g, and the second lithium-containing metal composite oxide has a specific surface area within the range of 0.5 ~ 30 m2/g. But, the particle size and the specific area are not limited to the above described ranges.
For example, in the case of LiCoO2 used as a first lithium-containing metal composite oxide, the particle size may be within the range of 10-20 IM1 the electrical conductivity may be about 10~2 S/cm, and the specific surface area may be about 0.2 m2/g. As a second lithium-containing metal composite oxide to be coated on the surface of the above described particle, LiMnO4, Li (Nii/3Mni/3Cθi/3) O2, LiFePO4, etc. may be used. In the case of LiFePO4 used as a second lithium- containing metal composite oxide, the particle size may be within the range of 0.5~5 μm, the electrical conductivity may be about 10~4 ~ 10"9 S/cm, and the specific surface area may be about 0.5 ~ 13 m2/g. When the whole or partial surface of LiFePO4 (the second lithium-containing metal composite oxide) is coated with a carbonaceous material, the conductivity may be increased up to the range of 10~2 ~ 10~3.
Non-limiting examples of a method of obtaining a cathode active material according to the present invention (in which the surface of a first lithium-containing metal composite oxide is coated with a second lithium-containing metal composite oxide) include jet mill, spray drying, etc. Preferably, a Mechanofusion method may be used, and also, a NOBILTA™ (Hosokawa Micron Corporation) , which has better milling power than the Mechanofusion method, may be used.
When a first lithium-containing metal composite oxide and a second lithium-containing metal composite oxide are charged in a Mechanofusion mixer, the materials are mixed by adding mechanical energy and thermal energy at the same time. Accordingly, it is possible to obtain a cathode active material in which the surface of a first lithium-containing metal composite oxide particle is uniformly coated with a second lithium-containing metal composite oxide. In a Mechanofusion method, when a high striking energy is added to particles, two kinds of particles are fused in such a manner that a base particle is completely surrounded by coating particles. For example, Such a coated particle is obtained by the steps of: fixing both kinds of powder on the inner wall of a rotative container by a centrifugal force; momentarily compacting the powder by an inner member fixed to a center shaft; scraping the powder with a scraper at a high speed; complexing the particles through repeated compacting/scraping (shearing) operation and heat-adhering both kinds of powder by a mechanofusion operation. However, this example is illustrative only, and the scope of the present invention is not limited thereto. In the present invention, particle hardness of the second lithium-containing metal composite oxide may be lower than that of the first lithium-containing metal composite oxide because, in the process of coating the second lithium- containing metal composite oxide on the surface of the first lithium-containing metal composite oxide by milling the two materials, the second lithium-containing metal composite oxide has to be finely ground so as to be uniformly coated on the surface of the first lithium-containing metal composite oxide. On the other hand, the first lithium-containing metal composite oxide does not have to be ground.
A cathode including the cathode active material according to the present invention is obtained by applying cathode slurry including the cathode active material according to the present invention on a current collector, and drying the applied slurry. Herein, a small amount of conductive material or binder may be optionally added.
Non-limiting examples of a cathode current collector include aluminum, nickel, and foil obtained by combination of aluminum and nickel. As a binder, a conventional binding agent may be used, and non-limiting examples of the binder include PVDF (polyvinylidene fluoride) , SBR (styrene butadiene rubber) , etc.
The present invention provides a secondary battery including a cathode including a first cathode active material surface-coated with a second cathode active material, an anode, electrolyte, and a separator, the second cathode active material having a relatively low potential and a high resistance.
It is preferable that the secondary battery is a lithium secondary battery, and non-limiting examples of the lithium secondary battery include a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, a lithium ion polymer secondary battery, etc.
The secondary battery according to the present invention may be obtained by a conventional method known to one skilled in the art in which a porous separator is inserted between a cathode and an anode, and electrolyte is added. An anode according to the present invention may be obtained by a conventional method known to one skilled in the art, that is, by applying anode slurry including an anode active material on a current collector, and drying the applied slurry. Herein, the anode active material may include a conventional anode active material that may be used in an anode of a conventional secondary battery, and non-limiting examples of the anode active material include lithium metal or lithium alloy, a lithium intercalating material, such as carbon, petroleum coke, activated carbon, graphite, or other carbons, etc.
The electrolyte for the battery includes conventional electrolyte components known to one skilled in the art, that is, electrolyte salts and an organic solvent.
An electrolyte salt that may be used in the present invention includes a salt represented by the formula of A+B", wherein A+ represents an alkali metal cation selected from the group including Li+, Na+, K+ and combinations thereof, and B- represents an anion selected from the group including PFβ~, BF4" , Cl", Br", I", ClO4 ", AsF6 ", CH3CO2 ", CF3SO3 ", N (CF3SO2) 2 ~, C (CF2SO2) 3 ~ and combinations thereof. A lithium salt is particularly preferred.
As an organic solvent, a conventional solvent known to one skilled in the art, that is, cyclic carbonate and/or linear carbonate, may be used, and non-limiting examples of such carbonate include propylene carbonate (PC) , ethylene carbonate (EC) , diethyl carbonate (DEC) , dimethyl carbonate (DMC) , dipropyl carbonate (DPC) , dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP) , ethyl methyl carbonate (EMC) , gamma-butyrolactone (GBL) , fluoroethylene carbonate (FEC), methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, pentyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, or a mixture thereof. Halogen derivatives of the above organic solvents may also be used.
There is no particular limitation in the separator that may be used in the present invention, as long as the separator is a porous material. Non-limiting examples of the separator that may be used include a polypropylene-based, polyethylene- based, polyolefin-based porous separator. Porous separators to which inorganic materials are added may also be used.
There is no particular limitation in the outer shape of the secondary battery according to the present invention. The secondary battery may be a cylindrical battery using a can, a prismatic battery, a pouch-type battery or a coin-type battery.
Brief Description of the Drawings
The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:
FIG. 1 is a scanning electron microscopy (SEM) picture of an active material LiCoC>2 surface-coated with LiFePO4, which is prepared by Example 1; FIG. 2 is a SEM picture of an active material LiCoO2 simply mixed with LiFePO4, which is prepared by Comparative Example 2;
FIG. 3 is a schematic drawing illustrating active materials according to Examples and Comparative Examples; FIGs. 4~8 illustrate DC impedance values of an active material LiCoO2 surface-coated with LiFePO4, which is prepared by Example 4, and DC impedance values of an active material LiCoO2, which is prepared by Comparative Example 1. FIG. 4, FIG. 5, FIG. 6, FIG. 7 and FIG. 8 illustrate the values at the current rates of 1C, 5C, 1OC, 2OC, and 3OC, respectively.
FIG. 9 is a SEM picture of an active material LiCoO2 surface-coated with LiFePO4, which is prepared by Example 5.
Best Mode for Carrying Out the Invention Reference will now be made in detail to the preferred embodiments of the present invention. However, the following examples are illustrative only, and the scope of the present invention is not limited thereto.
[Example 1]
LiCoO2 (specific surface area: 0.2 m2/g, D50 = 5 ~ 20 [M) and LiFePO4 (specific surface area: 13 m2/g, D50 = 0.5 ~ 5 β\a) were mixed in a weight ratio of 97.5: 2.5, and the mixture was charged into a mechanofusion mixer. A mechanofusion process was performed for 5-30 minutes to obtain LiCoO2 powder surface- coated with LiFePO4. Although the mechanofuxion process was performed at room temperature, the process inevitably generated considerable amount of heat. So, the coating of LiFePO4 is facilitated by the heat. FIG. 1 shows a scanning electron microscopy (SEM) picture of the obtained powder. Herein, the potential difference vs. lithium potential between the two materials was 0.3V ~ 0.8V, and the electrical conductivity ratio of LiFePO4 to LiCoO2 was 10"2 ~ 10~7.
As shown in FIG. 1, fine particles of LiFePO4 are uniformly coated on the surface of LiCoO2 particles .
The coated cathode active material, together with a conductive material and a binding agent, was added in a solvent NMP (N-methyl-2-pyrrolidone) , to obtain cathode slurry. Then, a cathode was obtained by coating the cathode slurry on Al current collector.
As an anode active material, a graphite material was used. A binding agent was added in NMP to obtain anode slurry. Then, an anode was obtained by coating the anode slurry on Cu current collector.
As electrolyte, EC/EMC (ethyl carbonate/ethyl methyl carbonate, volumetric ratio 1:2) solution containing IM LiPFβ dissolved therein was used. A polyolefin-based separator was inserted between the obtained cathode and anode, and then the electrolyte was charged to obtain a battery.
[Example 2]
A cathode active material and a battery were obtained in the same manner as described in Example 1, except that LiCoO2 and LiFePO4 were mixed in a weight ratio of 95: 5 instead of 97.5: 2.5.
[Example 3] A cathode active material and a battery were obtained in the same manner as described in Example 1, except that LiCoO2 and LiFePO4 were mixed in a weight ratio of 90: 10 instead of 97.5: 2.5. [Example 4]
A cathode active material and a battery were obtained in the same manner as described in Example 1, except that LiCoθ2 and LiFeP04 were mixed in a weight ratio of 85: 15 instead of 97.5: 2.5.
[Example 5]
A cathode active material and a battery were obtained in the same manner as described in Example 1, except that a NOBILTA™ (Hosokawa Micron Corporation) was performed instead of a mechanofusion method.
[Comparative Example 1] A cathode active material and a battery were obtained in the same manner as described in Example 1, except that LiCoO2 was used alone as a cathode active material.
[Comparative Example 2] A cathode active material and a battery were obtained in the same manner as described in Example 3 (LiCoO2: LiFeP04 = 90: 10), except that LiCoO2 and LiFePC>4 were simply mixed by a ball mill process, instead of a mechanofusion process.
[Comparative Example 3]
A cathode active material and a battery were obtained in the same manner as described in Example 1, except that
LiNi0.9C00.1O2 (specific surface area: 0.4 m2/g, D50 = 10 μm) , instead of LiFePO4, was coated on the surface of LiCoO2 via a mechanofusion process.
Herein, the potential difference vs. lithium potential between the two materials was -0.2V ~ 0.5V, and the electrical conductivity ratio of LiNi0.9Co0.1O2 to LiCoθ2 was 1. When the secondary battery according to Comparative Example 3 was used, the safety of a battery cannot be improved due to an inappropriate resistance ratio.
[Experimental Example 1] Determination on the safety of a battery
On each of the secondary batteries according to Examples 1~4 and the batteries according to Comparative Examples 1~3, a nail penetration test was performed with voltage of 4.2V at 60 °C.
As noted in Table 1, batteries according to Comparative Examples 1~3 caused fire, and on the other hand, batteries according to Examples 1-4 did not cause fire or explosion, and maintained safety. Therefore, although an internal short was caused by an external impact, it is possible to significantly reduce the momentary movement of a large amount of lithium ions, and the flow of current, from an anode to a cathode. In other words, heat accumulation of a battery, which is caused by the flow of current, is reduced, thereby suppressing sudden fire or explosion of a battery.
[Table 1]
0.3m/min lm/min 3m/min
Exp. 1 Pass (0/3) Pass (0/3) Pass (0/3)
Exp.2 Pass (0/3) Pass (0/3) Pass (0/3)
Exp.3 Pass (0/3) Pass (0/3) Pass (0/3)
Exp.4 Pass (0/3) Pass (0/3) Pass (0/3)
Comp. Exp. 1 Fail (3/3) Fail (3/3) Fail (3/3)
Comp. Exp. 2 Fail (3/3) Fail (3/3) Fail (3/3)
Comp. Exp. 3 Fail (3/3) Fail (3/3) Fail (3/3)
[Experimental Example 2] Determination on the resistance of a battery On each of the secondary battery according to Example 1 and the battery according to Comparative Example 1, an internal resistance (DC impedance) was measured by changing the current rate into 1C, 5C, 1OC, 2OC, and 3OC.
Based on the test results, as the current rate is increased, the difference in DC impedance between LiCoO2 surface-coated with LiFePO4 and uncoated LiCoO2 gets larger (see FIGs. 4-8) . Accordingly, it is determined that during discharge, LiFePO4 acting as a second lithium-containing metal composite oxide functions as a resistance.
Therefore, it is determined that during a discharge of 5C or more (for example, an internal short of a battery) in which the resistance difference of two or more kinds of cathode active materials occurs, the moving rate of a large amount of lithium ions and electrons from an anode to a cathode is decreased, thereby preventing the heat generation caused by the sudden occurrence of over current, thus improving the safety of a battery.
[Experimental Example 3] Determination on the thermal stability of a battery
The thermal stability of a battery was determined by using Differential Scanning Calorimetry (DSC) , and the performance of a battery was determined by manufacturing a coin half cell.
[Table 2]
Comp. Exp. Exp. 1 Comp. Exp.
1 2
Sample weight (mg) 9.0 9.0 9.0
Relative weight (%) OfLiCoO2 100 97.5 90
Figure imgf000022_0001
Based on the heat values as noted in Table 2, a surface- coated sample according to Example 1 has a lower value than an uncoated sample according to Comparative Example 1. Therefore, it is determined that the thermal stability of an active material of the battery according to Example 1 is better. On the other hand, the thermal stability of the battery according to Comparative Example 2, which is simply mixed sample, is not good.
Also, as noted in Table 2, at a low-rate, a surface- coated sample according to Example 1 shows similar performance to an uncoated sample according to Comparative Example 1. Therefore, it is determined that an active material according to the present invention may improve the stability while minimizing the reduction of battery performance. On the other hand, in the case of simply mixed sample according to Comparative Example 2, since the content of LiCoC>2 is decreased, the loss of capacity is unavoidable.
In the case of high-rates such as 5C, 1OC, 3OC, etc. (not noted in Table 2), as shown in FIGs. 4~8, since the resistance is increased, the performance of a battery is reduced and the moving rate of electrons and lithium ions is reduced. Therefore, it is possible to improve the safety at the occurrence of over current.
Industrial Applicability
In the present invention, an entire surface of a first lithium-containing metal composite oxide is coated with a second lithium-containing metal composite oxide having a high resistance value and a low potential vs. lithium potential. Therefore, during an internal short of a secondary battery, it is possible to slow down the moving rate of a large amount of lithium ions and electrons from an anode to a cathode, and thus to prevent heat generation caused by the occurrence of temporary over-current. Also, it is possible to increase the temperature where a cathode active material is decomposed and gas is generated, and to improve thermal stability by inhibiting side reactions of the cathode active material and electrolyte.
Also, since the second lithium-containing metal composite oxide is coated on the entire surface of the first lithium-containing metal composite oxide, a small amount of second lithium-containing metal composite oxide is required. Accordingly, it is possible to minimize the degradation of battery capacity and performance. While this invention has been described in connection with what is presently considered to be the most practical and exemplary embodiment, it is to be understood that the invention is not limited to the disclosed embodiment and the drawings, but, on the contrary, it is intended to cover various modifications and variations within the spirit and scope of the appended claims.

Claims

Claims
1. A cathode active material comprising:
(a) a first lithium-containing metal composite oxide; and (b) a second lithium-containing metal composite oxide coated on an entire surface of the first lithium-containing metal composite oxide particle,
Wherein the second lithium-containing metal composite oxide having a higher resistance and a lower potential vs. lithium potential (Li/Li+) than the first lithium-containing metal composite oxide.
2. The cathode active material according to claim 1, wherein the first lithium-containing metal composite oxide has a potential vs. lithium potential of 3.7 V or more (Li/Li+) , and the second lithium-containing metal composite oxide has a potential vs. lithium potential of less than 3.7 V (Li/Li+) .
3. The cathode active material according to claim 1, wherein a potential difference vs. lithium potential (ΔP) between the first lithium-containing metal composite oxide and the second lithium-containing metaL composite oxide is within a range of 0.3 V < Δ p < 5 V.
4. The cathode active material according to claim 1, wherein an electrical conductivity ratio of the second lithium-containing metal composite oxide to the first lithium- containing metal composite oxide is within a range of 10"1 ~ lO"7.
5. The cathode active material according to claim 1, wherein a whole or partial surface of the second lithium- containing metal composite oxide is coated with a conductive material.
6. The cathode active material according to claim 5, wherein the conductive material comprises a carbonaceous material.
7. The cathode active material according to claim 1, wherein a weight ratio of the first lithium-containing metal composite oxide to the second lithium-containing metal composite oxide is within a range of 70:30 ~ 97.5:2.5.
8. The cathode active material according to claim 1, wherein the first lithium-containing metal composite oxide has a particle size within a range of 5-30/M, and the second lithium-containing metal composite oxide has a particle size within a range of 30 nm ~ 5 μm.
9. The cathode active material according to claim 1, wherein the first lithium-containing metal composite oxide has a specific surface area within a range of 0.01 ~ 0.2 m2/g, and the second lithium-containing metal composite oxide has a specific surface area within a range of 0.5 ~ 30 m2/g.
10. The cathode active material according to claim 1, wherein the first lithium-containing metal composite oxide is selected from the group consisting of LiMO2(M = Co, Mn, Ni, Nii/3Cθi/3Mni/3, Cr, or V) and LiMO4(M = CoMn, NiV, CoV, CoP, MnP, NiP, or Mn2) , and the second lithium-containing metal composite oxide is selected from the group consisting of LiMθ4 (M = V2, or FeP), LiMO2(M = Mn, Mo, or W), LiV6Oi3, LiTiS2, and LiWO2.
11. The cathode active material according to claim 1, wherein the second lithium-containing metal composite oxide has a lower particle hardness than the first lithium- containing metal composite oxide.
12. A secondary battery comprising a cathode, an anode, electrolyte, and a separator, wherein the cathode comprises the cathode active material according to any one of claims 1 to 11.
13. The secondary battery according to claim 12, wherein during a discharge of 5C or more, a moving rate of a large amount lithium ions and electrons, which is suddenly transferred from an anode to a cathode, is adjusted to slowed down, thereby preventing fire occurrence of the battery.
PCT/KR2008/000305 2007-01-18 2008-01-18 Cathode active material and secondary battery comprising the same WO2008088180A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
CN200880002550.XA CN101595582B (en) 2007-01-18 2008-01-18 Cathode active material and secondary battery comprising the same
US12/523,392 US8084159B2 (en) 2007-01-18 2008-01-18 Cathode active material and secondary battery comprising the same
EP08704841.9A EP2108203B1 (en) 2007-01-18 2008-01-18 Cathode active material and secondary battery comprising the same
JP2009546325A JP5474563B2 (en) 2007-01-18 2008-01-18 Positive electrode active material and secondary battery including the same
US13/303,450 US8304111B2 (en) 2007-01-18 2011-11-23 Cathode active material and secondary battery comprising the same

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR10-2007-0005568 2007-01-18
KR20070005568 2007-01-18
KR20070022440 2007-03-07
KR10-2007-0022440 2007-03-07

Related Child Applications (2)

Application Number Title Priority Date Filing Date
US12/523,392 A-371-Of-International US8084159B2 (en) 2007-01-18 2008-01-18 Cathode active material and secondary battery comprising the same
US13/303,450 Continuation US8304111B2 (en) 2007-01-18 2011-11-23 Cathode active material and secondary battery comprising the same

Publications (1)

Publication Number Publication Date
WO2008088180A1 true WO2008088180A1 (en) 2008-07-24

Family

ID=39636141

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2008/000305 WO2008088180A1 (en) 2007-01-18 2008-01-18 Cathode active material and secondary battery comprising the same

Country Status (7)

Country Link
US (2) US8084159B2 (en)
EP (1) EP2108203B1 (en)
JP (2) JP5474563B2 (en)
KR (2) KR20080068593A (en)
CN (1) CN101595582B (en)
TW (2) TWI481100B (en)
WO (1) WO2008088180A1 (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008091074A1 (en) 2007-01-24 2008-07-31 Lg Chem, Ltd. A secondary battery with improved safety
JP2010086940A (en) * 2008-09-02 2010-04-15 Sumitomo Chemical Co Ltd Electrode active material, electrode, and nonaqueous electrolyte secondary battery
WO2011032264A1 (en) 2009-09-15 2011-03-24 HYDRO-QUéBEC Material consisting of composite oxide particles, method for preparing same, and use thereof as electrode active material
US20110300292A1 (en) * 2010-06-03 2011-12-08 Hon Hai Precision Industry Co., Ltd. Method for making lithium battery cathode composite material
EP2312677A3 (en) * 2009-10-16 2012-02-08 Sunyen Co., Ltd. Composite Positive Active Material of Lithium Battery and Method for Manufacturing the Same
WO2015003947A1 (en) 2013-07-08 2015-01-15 Basf Se Electrode materials for lithium ion batteries
JP2015028958A (en) * 2010-04-28 2015-02-12 株式会社半導体エネルギー研究所 Power storage device
JP2015035433A (en) * 2010-06-02 2015-02-19 株式会社半導体エネルギー研究所 Power storage device
WO2016095177A1 (en) 2014-12-18 2016-06-23 Dow Global Technologies Llc Lithium ion battery having improved thermal stability
US9911970B2 (en) 2013-07-09 2018-03-06 Dow Global Technologies Llc Lithium ion batteries
US10446833B2 (en) 2013-09-20 2019-10-15 Basf Se Electrode material including lithium transition metal oxide, lithium iron phosphate, further iron-phosphorous compound. and carbon, and lithium battery including the same

Families Citing this family (38)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2108203B1 (en) * 2007-01-18 2014-03-12 LG Chemical Limited Cathode active material and secondary battery comprising the same
JP5223281B2 (en) * 2007-09-28 2013-06-26 Ｔｄｋ株式会社 Lithium ion secondary battery or composite particle for positive electrode of lithium secondary battery, and lithium ion secondary battery or lithium secondary battery
US9172086B2 (en) 2008-12-05 2015-10-27 Samsung Sdi Co., Ltd. Cathode and lithium battery using the same
JP5673991B2 (en) * 2009-07-07 2015-02-18 三菱レイヨン株式会社 Dispersibility improver, thermoplastic resin composition, and molded article
CN111785958A (en) * 2010-06-29 2020-10-16 尤米科尔公司 High density and high voltage stable cathode material for secondary battery
CN110419131B (en) * 2010-06-29 2020-08-11 尤米科尔公司 High density and high voltage stable cathode material for secondary battery
JP2012048865A (en) * 2010-08-24 2012-03-08 Asahi Glass Co Ltd Method of manufacturing positive electrode active material for lithium ion secondary battery, positive electrode active material for lithium ion secondary battery, and lithium ion secondary battery
CN102792491A (en) 2010-09-30 2012-11-21 株式会社Lg化学 Cathode for lithium secondary battery and lithium secondary battery including same
JP5611066B2 (en) * 2011-01-20 2014-10-22 関東電化工業株式会社 Positive electrode active material and manufacturing method thereof
JP2012174485A (en) * 2011-02-22 2012-09-10 Fuji Heavy Ind Ltd Cathode active material and lithium ion power storage device using the same and manufacturing method thereof
KR101308677B1 (en) * 2011-05-31 2013-09-13 주식회사 코캄 Lithium secondary batteries
JP5696850B2 (en) * 2011-09-28 2015-04-08 三菱自動車工業株式会社 Secondary battery
KR101669111B1 (en) 2011-10-11 2016-10-26 삼성에스디아이 주식회사 Electrode active material for lithium secondary battery, preparing method thereof, electrode for lithium secondary battery including the same, and lithium secondary battery using the same
KR101515678B1 (en) 2011-12-07 2015-04-28 주식회사 엘지화학 Positive-electrode active material with improved output and secondary battery including them
CN104396082B (en) * 2012-04-13 2017-09-22 株式会社Lg化学 Battery system and its management equipment and method for the secondary cell including blended anode material
CN102779998A (en) * 2012-07-19 2012-11-14 东莞新能源科技有限公司 Lithium ion monomer battery capable of preventing overdischarge
US9917301B2 (en) * 2012-08-01 2018-03-13 Ningbo Institute Of Materials Technology & Engineering Chinese Academy Of Sciences Solid solution composite LIMVO4-LINI-X-YCOXMNYO2 material for rechargeable lithium ion batteries
WO2015001632A1 (en) * 2013-07-03 2015-01-08 株式会社日立製作所 Cathode material for lithium ion secondary battery, cathode for lithium ion secondary battery, lithium ion secondary battery, and method for producing each of same
JP6132164B2 (en) * 2014-04-25 2017-05-24 株式会社豊田自動織機 Positive electrode for non-aqueous secondary battery and non-aqueous secondary battery
KR101764266B1 (en) 2014-12-02 2017-08-04 주식회사 엘지화학 Electrolyte Solution for Lithium Secondary Battery with Improved Low Temperature Performance and Lithium Secondary Battery Comprising The Same
JP2017111930A (en) * 2015-12-15 2017-06-22 トヨタ自動車株式会社 All-solid battery and production method thereof
CN107154491B (en) * 2016-03-04 2020-12-22 中国科学院宁波材料技术与工程研究所 High-efficiency lithium ion battery positive electrode material and preparation method and application thereof
KR102670558B1 (en) * 2016-03-15 2024-05-28 삼성에스디아이 주식회사 Positive active material for rechargeable lithium battery and rechargeable lithium battery including same
EP3465805B1 (en) * 2016-05-27 2021-08-18 Umicore Positive electrode for lithium ion battery
CN106159241A (en) * 2016-08-31 2016-11-23 四川剑兴锂电池有限公司 A kind of anode pole piece and the amorphous carbon lithium battery containing this positive plate
CN106129380A (en) * 2016-08-31 2016-11-16 四川剑兴锂电池有限公司 A kind of anode pole piece and the amorphous carbon lithium battery containing this positive plate
US20180083315A1 (en) * 2016-09-16 2018-03-22 Robert Bosch Gmbh Coated Cathode Active Material for Engineered Solid-State Battery Interfaces
CN106654224B (en) * 2017-01-16 2019-11-29 湖南瑞翔新材料股份有限公司 A kind of cobalt acid lithium composite material and preparation method, positive electrode
DE102017201313A1 (en) * 2017-01-27 2018-08-02 Robert Bosch Gmbh Stabilized active material for lithium-ion batteries
JP6410384B1 (en) * 2017-05-29 2018-10-24 太平洋セメント株式会社 Positive electrode active material composite for lithium ion secondary battery or positive electrode active material composite for sodium ion secondary battery, secondary battery using these, and production method thereof
CN109004174A (en) * 2017-06-06 2018-12-14 宁德时代新能源科技股份有限公司 Positive plate, preparation method thereof and all-solid-state lithium secondary battery using positive plate
CN109428066A (en) * 2017-08-30 2019-03-05 中国科学院宁波材料技术与工程研究所 Core-shell material and preparation method thereof, lithium ion battery negative material and lithium ion battery
US12080861B2 (en) * 2018-02-20 2024-09-03 Hulico LLC Recycling of coated electrode materials
JP6590973B2 (en) * 2018-03-23 2019-10-16 太平洋セメント株式会社 Positive electrode active material composite for lithium ion secondary battery and method for producing the same
JP7336680B2 (en) * 2018-10-30 2023-09-01 パナソニックＩｐマネジメント株式会社 secondary battery
CN113939928B (en) * 2019-06-27 2024-09-17 东丽株式会社 Positive electrode for lithium ion secondary battery and lithium ion secondary battery
CN112242519B (en) * 2019-07-17 2023-01-06 比亚迪股份有限公司 Positive electrode material, preparation method thereof and solid-state lithium battery
WO2023033009A1 (en) * 2021-08-31 2023-03-09 古河電池株式会社 Positive electrode for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001110414A (en) * 1999-10-04 2001-04-20 Nippon Telegr & Teleph Corp <Ntt> Material for activating positive electrode of lithium secondary battery and the lithium secondary battery
JP2002279989A (en) * 2001-03-16 2002-09-27 Sony Corp Battery
KR20040003738A (en) * 2002-07-04 2004-01-13 한국전기연구원 Method of fabricating electrode of Lithium secondary battery and Lithium secondary battery with the electrode

Family Cites Families (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2561556B2 (en) * 1990-08-24 1996-12-11 本田技研工業株式会社 Positive electrode active material for lithium secondary battery
JP3111791B2 (en) * 1994-02-21 2000-11-27 松下電器産業株式会社 Non-aqueous electrolyte secondary battery
JP3077508B2 (en) * 1994-05-06 2000-08-14 松下電器産業株式会社 Non-aqueous electrolyte lithium secondary battery
JP3577907B2 (en) * 1996-11-06 2004-10-20 株式会社デンソー Method for producing positive electrode for non-aqueous electrolyte secondary battery
JPH1154119A (en) * 1997-08-04 1999-02-26 Toshiba Battery Co Ltd Lithium secondary battery
JP3595734B2 (en) * 1999-02-15 2004-12-02 株式会社デンソー Positive active material for non-aqueous electrolyte secondary battery, method for producing the positive active material, and secondary battery using the positive active material
JP3362025B2 (en) * 1999-04-30 2003-01-07 同和鉱業株式会社 Positive electrode active material and lithium secondary battery using the positive electrode active material
JP3959929B2 (en) * 2000-04-25 2007-08-15 ソニー株式会社 Positive electrode and non-aqueous electrolyte battery
JP4716072B2 (en) * 2001-07-02 2011-07-06 株式会社豊田中央研究所 Lithium vanadium composite oxide for negative electrode active material of water based lithium secondary battery, method for producing the same, and lithium secondary battery using the same
JP2002075368A (en) * 2000-09-05 2002-03-15 Sony Corp Positive electrode active material, nonaqueous electrolyte battery, and their manufacturing method
KR100404891B1 (en) * 2001-03-13 2003-11-10 주식회사 엘지화학 Positive active material for lithium secondary battery and method for preparing the same
JP4510331B2 (en) * 2001-06-27 2010-07-21 パナソニック株式会社 Nonaqueous electrolyte secondary battery
JP4180363B2 (en) * 2002-01-31 2008-11-12 日本化学工業株式会社 Ferrous phosphate hydrate salt crystal, method for producing the same, and method for producing lithium iron phosphorus composite oxide
JP2003272618A (en) * 2002-03-12 2003-09-26 Mitsubishi Electric Corp Positive electrode active material and its manufacturing method as well as lithium ion secondary battery using said positive electrode active material
JP2004014405A (en) * 2002-06-10 2004-01-15 Japan Storage Battery Co Ltd Non-aqueous electrolyte secondary battery
KR20050094346A (en) 2002-06-21 2005-09-27 유미코르 Carbon-coated li-containing powders and process for production thereof
CA2394056A1 (en) 2002-07-12 2004-01-12 Hydro-Quebec Particles with a non-conductive or semi-conductive core covered by a conductive layer, the processes for obtaining these particles and their use in electrochemical devices
JP3632686B2 (en) * 2002-08-27 2005-03-23 ソニー株式会社 Positive electrode active material and non-aqueous electrolyte secondary battery
JP4061586B2 (en) * 2003-04-11 2008-03-19 ソニー株式会社 Positive electrode active material for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery using the same
JP4641375B2 (en) * 2003-10-20 2011-03-02 日立マクセル株式会社 Method for producing composite of olivine type lithium phosphate and carbon material
JP5135664B2 (en) * 2003-12-05 2013-02-06 日産自動車株式会社 Cathode material for non-aqueous electrolyte lithium ion battery and battery using the same
US8617745B2 (en) * 2004-02-06 2013-12-31 A123 Systems Llc Lithium secondary cell with high charge and discharge rate capability and low impedance growth
JP2005302300A (en) * 2004-03-19 2005-10-27 Sanyo Electric Co Ltd Nonaqueous electrolyte battery
US7381496B2 (en) * 2004-05-21 2008-06-03 Tiax Llc Lithium metal oxide materials and methods of synthesis and use
JP4923397B2 (en) * 2004-09-06 2012-04-25 日産自動車株式会社 Non-aqueous electrolyte lithium ion secondary battery positive electrode material and method for producing the same
CN1855587B (en) * 2005-04-28 2010-05-05 比亚迪股份有限公司 Battery anode preparation method and preparation method of lithium ion batteries using the battery anode
US8445129B2 (en) * 2005-05-27 2013-05-21 Sony Corporation Cathode active material, method of manufacturing it, cathode, and battery
JP4869629B2 (en) * 2005-05-30 2012-02-08 住友大阪セメント株式会社 Method for producing positive electrode active material for lithium battery, positive electrode active material for lithium battery, and lithium battery
EP2108203B1 (en) * 2007-01-18 2014-03-12 LG Chemical Limited Cathode active material and secondary battery comprising the same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001110414A (en) * 1999-10-04 2001-04-20 Nippon Telegr & Teleph Corp <Ntt> Material for activating positive electrode of lithium secondary battery and the lithium secondary battery
JP2002279989A (en) * 2001-03-16 2002-09-27 Sony Corp Battery
KR20040003738A (en) * 2002-07-04 2004-01-13 한국전기연구원 Method of fabricating electrode of Lithium secondary battery and Lithium secondary battery with the electrode

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP2108203A4 *

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008091074A1 (en) 2007-01-24 2008-07-31 Lg Chem, Ltd. A secondary battery with improved safety
EP2108202A1 (en) * 2007-01-24 2009-10-14 LG Chem, Ltd. A secondary battery with improved safety
EP2108202A4 (en) * 2007-01-24 2011-08-10 Lg Chemical Ltd A secondary battery with improved safety
JP2010086940A (en) * 2008-09-02 2010-04-15 Sumitomo Chemical Co Ltd Electrode active material, electrode, and nonaqueous electrolyte secondary battery
CN102498596A (en) * 2009-09-15 2012-06-13 魁北克水电公司 Material consisting of composite oxide particles, method for preparing same, and use thereof as electrode active material
WO2011032264A1 (en) 2009-09-15 2011-03-24 HYDRO-QUéBEC Material consisting of composite oxide particles, method for preparing same, and use thereof as electrode active material
US20120237833A1 (en) * 2009-09-15 2012-09-20 Abdelbast Guerfi Material consisting of composite oxide particles, method for preparing same, and use thereof as electrode active material
US9431675B2 (en) 2009-09-15 2016-08-30 Hydro-Quebec Material consisting of composite oxide particles, method for preparing same, and use thereof as electrode active material
KR101897645B1 (en) * 2009-09-15 2018-09-12 하이드로-퀘벡 Material consisting of composite oxide particles, method for preparing same, and use thereof as electrode active material
EP2478580B1 (en) * 2009-09-15 2021-12-08 Hydro-Québec Material consisting of composite oxide particles, method for preparing same, and use thereof as electrode active material
JP2013504858A (en) * 2009-09-15 2013-02-07 イドロ−ケベック Materials comprising composite oxide particles, their production method, and their use as electrode active materials
JP2015065171A (en) * 2009-09-15 2015-04-09 イドロ−ケベックＨｙｄｒｏ−Ｑｕｅｂｅｃ Material comprising composite oxide particle, method for preparing the same, and use thereof as electrode active material
EP2312677A3 (en) * 2009-10-16 2012-02-08 Sunyen Co., Ltd. Composite Positive Active Material of Lithium Battery and Method for Manufacturing the Same
JP2015028958A (en) * 2010-04-28 2015-02-12 株式会社半導体エネルギー研究所 Power storage device
JP2015035433A (en) * 2010-06-02 2015-02-19 株式会社半導体エネルギー研究所 Power storage device
US9929402B2 (en) 2010-06-02 2018-03-27 Semiconductor Energy Laboratory Co., Ltd. Power storage device
US8455139B2 (en) * 2010-06-03 2013-06-04 Tsinghua University Method for making lithium battery cathode composite material of lithium iron phosphate/lithium vanadium phosphate composite
US20110300446A1 (en) * 2010-06-03 2011-12-08 Hon Hai Precision Industry Co., Ltd. Lithium battery cathode composite material
US20110300292A1 (en) * 2010-06-03 2011-12-08 Hon Hai Precision Industry Co., Ltd. Method for making lithium battery cathode composite material
WO2015003947A1 (en) 2013-07-08 2015-01-15 Basf Se Electrode materials for lithium ion batteries
US10026954B2 (en) 2013-07-08 2018-07-17 Basf Se Electrode materials for lithium ion batteries
US9911970B2 (en) 2013-07-09 2018-03-06 Dow Global Technologies Llc Lithium ion batteries
US10446833B2 (en) 2013-09-20 2019-10-15 Basf Se Electrode material including lithium transition metal oxide, lithium iron phosphate, further iron-phosphorous compound. and carbon, and lithium battery including the same
WO2016095177A1 (en) 2014-12-18 2016-06-23 Dow Global Technologies Llc Lithium ion battery having improved thermal stability
US11251419B2 (en) 2014-12-18 2022-02-15 Dow Global Technologies Llc Lithium ion battery having improved thermal stability

Also Published As

Publication number Publication date
US8084159B2 (en) 2011-12-27
JP2010517218A (en) 2010-05-20
JP5474563B2 (en) 2014-04-16
TWI458162B (en) 2014-10-21
TW200841507A (en) 2008-10-16
KR101293265B1 (en) 2013-08-09
JP2014075352A (en) 2014-04-24
US20120100430A1 (en) 2012-04-26
CN101595582A (en) 2009-12-02
CN101595582B (en) 2015-03-25
EP2108203A1 (en) 2009-10-14
EP2108203B1 (en) 2014-03-12
TW201347277A (en) 2013-11-16
US20100028776A1 (en) 2010-02-04
US8304111B2 (en) 2012-11-06
TWI481100B (en) 2015-04-11
EP2108203A4 (en) 2011-02-16
KR20100130973A (en) 2010-12-14
KR20080068593A (en) 2008-07-23

Similar Documents

Publication Publication Date Title
US8304111B2 (en) Cathode active material and secondary battery comprising the same
EP3291338B1 (en) Cathode for lithium-sulfur battery, manufacturing method therefor, and lithium-sulfur battery containing same
JP5882516B2 (en) Lithium secondary battery
US7875388B2 (en) Electrodes including polyacrylate binders and methods of making and using the same
JP4725594B2 (en) Method for manufacturing lithium secondary battery
JP4650603B2 (en) Anode material for secondary battery, method for producing the same, and secondary battery using the same
US10862108B2 (en) Positive electrode for a lithium electrochemical cell
WO2009014399A2 (en) Electrode active material having core-shell structure
US20060194119A1 (en) Lithium secondary battery with high performance
EP2160788A1 (en) Non-aqueous electrolyte and lithium secondary battery having the same
EP3121874A1 (en) Cathodes for lithium ion batteries comprising solid lithium oxalate
WO2023212540A1 (en) Polymer-supported and lithiophilic material impregnated carbon fiber protection for li-metal stability
JP2020047608A (en) Negative electrode material for lithium ion battery, negative electrode for lithium ion battery, and lithium ion battery
WO2014115322A1 (en) Negative electrode active material for lithium ion secondary cell, and lithium ion secondary cell obtained using same
US9172089B2 (en) Anode active material, method of preparing the same, anode including the anode active material, and lithium battery including the anode
KR20240056447A (en) Method of manufacturing electrode for rechargeable lithium battery, electrode manufactured therefrom, and rechargeable lithium battery including the electrode
EP3255706A1 (en) Process for treating a cathode material
JP2002313334A (en) Negative electrode material for use in nonaqueous electrolyte secondary battery and manufacturing method therefor

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 200880002550.X

Country of ref document: CN

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 08704841

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2008704841

Country of ref document: EP

ENP Entry into the national phase

Ref document number: 2009546325

Country of ref document: JP

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 12523392

Country of ref document: US

NENP Non-entry into the national phase

Ref country code: DE