[DESCRIPTION]
ANODE ACTIVE MATERIAL AND SECONDARY BATTERY COMPRISING
THE SAME
[TECHNICAL FIELD]
5 The present invention relates to an anode active material and a secondary
battery comprising the same. More specifically, the present invention relates to an
anode active material for secondary batteries, capable of intercalating and
deintercalating ions, comprising: a core comprising a crystalline carbon-based material;
and a composite coating layer comprising one or more materials selected from the group
10 consisting of low crystalline carbon and amorphous carbon, and a hydrophilic material
containing oxide capable of intercalating and deintercalating ions, wherein the
composite coating layer comprises: a matrix comprising one component selected from
one or more materials selected from the group consisting of low crystalline carbon and
amorphous carbon, and a hydrophilic material containing oxide capable of intercalating
15 and deintercalating ions; and a filler comprising the other component, incorporated in
the matrix.
[BACKGROUND ART]
-1-
Technological development and increased demand for mobile equipment have
led to a rapid increase in demand for secondary batteries as energy sources. Among
these secondary batteries, lithium secondary batteries having high energy density and
voltage, long cycle span and low self-discharge are commercially available and widely
5 used.
In addition, increased interest in environmental issues has brought about a great
deal of research associated with electric vehicles, hybrid electric vehicles and plug-in
hybrid electric vehicles as alternatives to vehicles using fossil fuels such as gasoline
vehicles and diesel vehicles which are major causes of air pollution. These electric
10 vehicles generally use nickel-metal hydride (Ni-MH) secondary batteries as power
sources. However, a great deal of study associated with use of lithium secondary
batteries with high energy density, discharge voltage and power stability is currently
underway and some are commercially available.
A lithium secondary battery has a structure in which a non-aqueous electrolyte
15 comprising a lithium salt is impregnated into an electrode assembly comprising a
cathode and an anode, each comprising an active material coated on a current collector,
and a porous separator interposed therebetweeii.
Lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium
composite oxide and the like are generally used as cathode active materials of lithium
-2-
secondary batteries and carbon-based materials are generally used as anode active
materials thereof. Use of silicon compounds, sulfur compounds and the like has also
been considered.
However, lithium secondary batteries have various problems, in particular,
5 problems associated with fabrication and driving properties of an anode.
First, regarding fabrication of an anode, a carbon-based material used as an
anode active material is highly hydrophobic and thus has problems of low miscibility
with a hydrophilic solvent in the process of preparing a slurry for electrode fabrication
and low dispersion uniformity of solid components. In addition, this hydrophobicity
10 of the anode active material complicates impregnation of highly polar electrolytes in the
battery fabrication process. The electrolyte impregnation process is a kind of
bottleneck in the battery fabrication process, thus greatly decreasing productivity.
In order to solve these problems, addition of a surfactant to an anode, an
electrolyte or the like is suggested. However, disadvantageously, the surfactant may
15 have side effects on driving properties of batteries.
Meanwhile, regarding driving properties of the anode, disadvantageously, the
carbon-based anode active material induces initial irreversible reaction, since a solid
electrolyte interface (SEI) layer is formed on the surface of the carbon-based anode
active material during an initial charge/discharge process (activation process), and
-3-
i
battery capacity is reduced due to exhaustion of the electrolyte caused by removal
(breakage) and regeneration of the SEI layer during a continuous charge/discharge
process.
In order to solve these problems, various methods such as formation of an SEI
5 layer through stronger bond, or formation of an oxide layer on the surface of the anode
active material have been attempted. These methods have properties unsuitable for
commercialization such as deterioration in electrical conductivity caused by the oxide
layer and deterioration in productivity caused by additional processes. Also, there still
exists a problem in that growth of lithium dendrites on the surface of the anode active
10 material may cause short-circuit.
Accordingly, there is an increasing need for secondary batteries capable of
solving these problems.
[DISCLOSURE]
[TECHNICAL PROBLEM]
15 Therefore, the present invention has been made to solve the above and other
technical problems that have yet to be resolved.
As a result of a variety of extensive and intensive studies and experiments to
solve the problems as described above, the present inventors discovered that, when an
-4-
anode active material is produced by forming a composite coating layer on a crystalline
carbon-based core, various problems associated with anode fabrication and battery
driving properties can be solved. The present invention has been completed, based on
this discovery.
5 [TECHNICAL SOLUTION]
In accordance with one aspect of the present invention, provided is an anode
active material for secondary batteries, capable of intercalating and deintercalating ions,
comprising: a core comprising a crystalline carbon-based material; and a composite
coating layer comprising one or more materials selected from the group consisting of
10 low crystalline carbon and amorphous carbon, and a hydrophilic material containing
oxide capable of intercalating and deintercalating ions, wherein the composite coating
layer comprises: a matrix comprising one component selected from (a) the one or more
materials selected from the group consisting of low crystalline carbon and amorphous
carbon and (b) the hydrophilic material containing oxide capable of intercalating and
15 deintercalating ions; and a filler comprising the other component, incorporated in the
matrix.
As such, the anode active material having a structure in which the core
comprising a crystalline carbon-based material is coated with the composite coating
layer having a matrix/filler structure comprising one or more materials selected from the
-5-
group consisting of low crystalline carbon and amorphous carbon, and a hydrophilic
material containing oxide capable of intercalating and deintercalating ions can solve the
problems in the related art, based on a specific active material structure and
components.
5 First, the surface of the oxide capable of intercalating and deintercalating ions
comprised as a matrix or filler component in the composite coating layer exhibits high
miscibility with a hydrophilic solvent in a slurry for fabrication of an anode according
to the type of materials used, thus improving dispersibility in solid components in the
slurry. Accordingly, when an anode is fabricated by applying this slurry to a current
10 collector, distribution uniformity between components such as a binder and the anode
active material can be improved and superior electrode properties can thus be obtained.
The improvement in uniformity caused by the hydrophilic material can
i
! minimize a decrease in bonding strength between the slurry and the partial current
| collector which occurs on the non-uniform electrode. The hydrophilic material
i
i
15 improves affinity between the active material layer and the surface of the current
collector, and bonding strength between the active material layer and the current
collector and thereby solves a problem of increase in internal resistance caused by
separation of the active material layer from the current collector.
-6-
!
Similarly, the hydrophilic material containing oxide capable of intercalating
and deintercalating ions comprised in the composite coating layer imparts relatively
high hydrophilicity to at least a part of the anode active material, thereby greatly
reducing impregnation time of the highly polar electrolyte in the electrode fabrication
5 process and considerably improving battery productivity.
Second, the hydrophilic material containing oxide capable of intercalating and
deintercalating ions comprised in the composite coating layer forms a layer that has the
same function as SEI having a strong chemical bond and has a stronger bond to the
surface of the anode, thereby reducing an amount of irreversible ions required for
10 formation of the SEI layer, minimizing collapse of the SEI layer during repeated charge
and discharge and ultimately improving battery lifespan.
Third, the oxide capable of intercalating and deintercalating ions comprised as
a matrix or filler in the composite coating layer minimizes deterioration in electrical
conductivity which may be induced by presence of materials incapable of intercalating
15 and deintercalating ions.
Also, in the case of a lithium secondary battery, growth of lithium dendrites
may occur, since the crystalline carbon-based material serving as a core has a similar
electric potential to lithium, but this growth can be inhibited by coating a hydrophilic
-7-
material on the surface of the crystalline carbon-based material at a high oxidationreduction
potential.
[BEST MODE]
Hereinafter, the present invention will be described in detail.
5 As described above, the anode active material according to the present
invention comprises: a core comprising a crystalline carbon-based material; and a
composite coating layer comprising: a matrix comprising one component (for example,
amorphous carbon) selected from one or more materials selected from the group
consisting of low crystalline carbon and amorphous carbon, and a hydrophilic material
10 containing oxide capable of intercalating and deintercalating ions; and a filler
comprising the other component (for example, a hydrophilic material containing oxide
capable of intercalating and deintercalating ions,), incorporated in the matrix.
Generally, a carbon-based material is classified into graphite having a complete
layered crystal structure such as natural graphite, soft carbon having a low-crystalline
15 layered crystal structure (graphene structure in which hexagonal honeycomb shaped
planes of carbon are arrayed in the form of a layer), and hard carbon having a structure
in which the low-crystalline structures are mixed with non-crystalline parts.
-8-
In a preferred embodiment, the core component of the present invention,
namely the crystalline carbon-based material, may be graphite or a mixture of graphite
and low crystalline carbon, and one of the composite coating layer components may be
low-crystalline carbon, amorphous carbon or a mixture thereof.
5 Meanwhile, there is no limitation as to the hydrophilic material containing
oxide capable of intercalating and deintercalating ions which is another component
constituting the composite coating layer in the present invention so long as it exhibits
relatively high hydrophilicity and polarity to one or more materials selected from the
group consisting of low crystalline carbon and amorphous carbon and does not have a
10 negative effect on driving characteristics of batteries. Preferably, the hydrophilic
material is a metal oxide, lithium metal composite oxide or the like that is capable of
intercalating and deintercalating ions. This substance may be used alone or in
combination thereof.
The metal is preferably titanium, a metalloid or a mixture thereof and is more
15 preferably titanium, but is not limited thereto.
In one embodiment, the oxide capable of intercalating and deintercalating ions
is a substance represented by the following Formula 1.
Li4Ti5.xMxOi2-y-zAy(l)
-9-
wherein M is at least one selected from the group consisting of Mo, W, Zr, Hf,
Mn, Fe, Co, Ni, Zn, Al and Mg, A is at least one selected from the group consisting of
S, Se and Te, and 0< x< 1, 0< y< 2, and 0< z< 0.02.
The substance has defects in an oxygen position. When an amount of the
5 defects is excessively high, disadvantageous^, a stable crystal structure cannot be
maintained. Preferably, z is 0.02 or less.
In another embodiment, the oxide capable of intercalating and deintercalating
ions is Ti02 or LiTi204, but is not limited thereto.
The titanium oxide or lithium titanium oxide is a substance that forms a voltage
10 not lower than 0V and lower than 2V with respect to the lithium metal standard
electrode and has a voltage higher than that of graphite having a substantially equivalent
voltage to lithium. Accordingly, the titanium oxide or lithium titanium oxide causes
intercalation and deintercalation of lithium ions into the oxide, when power is
instantaneously applied at a low temperature due to relatively high voltage and may
15 provide an instant power which cannot be realized by carbon-based anode active
materials.
i
Also, in the case of lithium secondary batteries, titanium oxide or lithium
titanium oxide can inhibit lithium dendrites due to the difference in voltage.
-10-
In the present invention, the structure of the composite coating layer may be
determined, depending on matrix and filler components.
In a first exemplary structure, a filler comprising a hydrophilic material
containing oxide capable of intercalating and deintercalating ions is incorporated in a
5 matrix comprising one or more materials selected from the group consisting of low
crystalline carbon and amorphous carbon.
In a second exemplary structure, a filler comprising one or more materials
selected from the group consisting of low crystalline carbon and amorphous carbon is
incorporated in a matrix comprising a hydrophilic material containing oxide capable of
10 intercalating and deintercalating ions.
In the composite coating layer, since the matrix has a structure, components of
which have a continuous phase and the filler has a structure, components of which have
independent phases, the content of the matrix component is not necessarily greater than
the content of the filler component.
15 In the composite coating layer, the content of one or more materials selected
from the group consisting of low crystalline carbon and amorphous carbon, and the
content of the a hydrophilic material containing oxide capable of intercalating and
deintercalating ions are not particularly limited so long as the intended effects of the
present invention (described above) can be exerted. In a preferred embodiment, the
-11-
content of one or more materials selected from the group consisting of low crystalline
carbon and amorphous carbon may be 10 to 95% by weight, based on the total amount
of the composite coating layer and the content of the hydrophilic material containing
oxide capable of intercalating and deintercalating ions, may be 5 to 90% by weight,
5 based on the total amount of the composite coating layer.
The amount (coating amount) of the composite coating layer is preferably 0.1
to 20% by weight, based on the total amount of the anode active material. When the
amount of the composite coating layer is excessively low or the thickness thereof is
excessively small, effects caused by formation of the composite coating layer may not
10 be obtained and, on the other hand, when the amount of the composite coating layer is
excessively high or the thickness thereof is excessively great, disadvantageous^, the
desired core-composite coating layer structure may not be formed and capacity may be
deteriorated.
The present invention also provides an anode mix comprising the anode active
15 material.
The anode mix according to the present invention comprises 1 to 20% by
weight of a binder, and optionally comprises 0 to 20% by weight of a conductive
material, based on the total weight of the anode mix.
-12-
Examples of the binder include polytetrafiuoroethylene (PTFE), polyvinylidene
fluoride (PVdF), cellulose, polyvinyl alcohol, carboxymethylcellulose (CMC), starch,
hydroxypropylcellulose, regenerated cellulose, polyvinyl pyrollidone,
tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymers
5 (EPDM), sulfonated EPDM, styrene butadiene rubbers, fluoro-rubbers, various
copolymers, and polymer-saponified polyvinyl alcohol.
Any conductive material may be used without particular limitation so long as
it has suitable conductivity without causing chemical changes in the fabricated battery.
Examples of conductive materials include graphite; carbon blacks such as carbon black,
10 acetylene black, Ketjen black, channel black, furnace black, lamp black and thermal
black; conductive fibers such as carbon fibers and metallic fibers; metallic powders such
as carbon fluoride powder, aluminum powder and nickel powder; conductive whiskers
such as zinc oxide and potassium titanate; conductive metal oxides such as titanium
oxide; and polyphenylene derivatives. Specific examples of commercially available
15 conductive materials may include various acetylene black products (available from
Chevron Chemical Company, Denka Singapore Private Limited and Gulf Oil
Company), Ketjen Black EC series (available from Armak Company), Vulcan XC-72
(available from Cabot Company) and Super P (Timcal Co.).
If desired, a filler is optionally added to inhibit expansion of the anode. Any
20 filler may be used without particular limitation so long as it does not cause adverse
-13-
chemical changes in the manufactured battery and is a fibrous material. Examples of
the filler include olefin polymers such as polyethylene and polypropylene; and fibrous
materials such as glass fibers and carbon fibers.
Other components such as viscosity controllers or adhesion promoters may be
5 added alone or in combination.
The viscosity controller is a component to control the viscosity of the electrode
mix and thereby facilitate mixing of the electrode mix and application of the same to a
current collector and is present in an amount of 30% by weight or less, based on the
total weight of the anode mix. Examples of the viscosity controller include, but are not
10 limited to, carboxymethyl cellulose and polyvinylidene fluoride. In some cases, the
afore-mentioned solvent may also act as the viscosity controller.
The adhesion promoter is an auxiliary ingredient to improve adhesion of an
active material to a current collector and is present in an amount of 10% by weight,
based on the binder and examples thereof include oxalic acid, adipic acid, formic acid,
15 acrylic acid derivatives and itaconic acid derivatives.
The present invention also provides an anode for secondary batteries in which
the anode mix is applied to a current collector.
-14-
For example, the anode is produced by adding an anode material containing an
anode active material, a binder or the like to a solvent such as NMP to prepare a slurry,
and applying the slurry to an anode current collector, followed by drying and pressing.
The anode current collector is generally fabricated to have a thickness of 3 to
5 500 |un. Any anode current collector may be used without particular limitation so long
as it has suitable conductivity without causing adverse chemical changes in the
fabricated battery. Examples of the anode current collector include copper, stainless
steel, aluminum, nickel, titanium, sintered carbon, and copper or stainless steel
surface-treated with carbon, nickel, titanium or silver, and aluminum-cadmium alloys.
10 The anode current collector includes fine irregularities on the surface thereof so as to
enhance adhesion of anode active materials. In addition, the current collectors may be
used in various forms including films, sheets, foils, nets, porous structures, foams and
non-woven fabrics.
The present invention also provides a secondary battery comprising the anode
15 and the battery is preferably a lithium secondary battery.
The lithium secondary battery has a structure in which a lithium salt-containing
non-aqueous electrolyte is impregnated into an electrode assembly comprising a
separator interposed between the cathode and the anode.
-15-
For example, the cathode is prepared by applying a cathode active material to a
cathode current collector, followed by drying and pressing and further optionally
comprises other components such as binders or conductive materials as described above
associated with the configuration of the anode.
5 The cathode current collector is generally manufactured to have a thickness of
3 to 500 p . Any cathode current collector may be used without particular limitation
so long as it has suitable conductivity without causing adverse chemical changes in the
fabricated battery. Examples of the cathode current collector include stainless steel,
aluminum, nickel, titanium, sintered carbon, and aluminum or stainless steel surface-
10 treated with carbon, nickel, titanium or silver. Similar to the anode current collector,
the cathode current collectors include fine irregularities on the surface thereof so as to
enhance adhesion to the cathode active material. In addition, the cathode current
collector may be used in various forms including films, sheets, foils, nets, porous
structures, foams and non-woven fabrics.
15 The cathode active material is a lithium transition metal oxide comprising two
or more transition metals as a substance that causes electrochemical reaction, and
examples thereof include, but are not limited to, layered compounds such as lithium
cobalt oxide (LiCoC^) or lithium nickel oxide (LiNiC^) substituted by one or more
transition metals; lithium manganese oxide substituted by one or more transition metals;
20 lithium nickel oxide represented by the formula of LiNii.yMy02 (in which M = Co, Mn,
-16-
B
Al, Cu, Fe, Mg, B, Cr, Zn or Ga, the lithium nickel oxide including one or more
elements among the elements, 0.014, LiBF4, LiN(S02CF3)2,
to a mixed solvent of a cyclic carbonate such as EC or PC as a highly dielectric solvent
and linear carbonate such as DEC, DMC or EMC as a low-viscosity solvent.
Accordingly, the present invention provides a middle- or large-sized battery
pack comprising the secondary battery as a unit cell.
!
10 The middle- or large-sized battery pack has a considerably large battery cell
(unit cell) size, as compared to a small battery pack in order to obtain high capacity and
is thus more generally used in the process of impregnating an electrolyte or the like.
Accordingly, according to the present invention, an anode comprising an oxide capable
of intercalating and deintercalating ions is preferred in consideration of substantial
15 reduction in impregnation time.
Preferably, examples of the battery pack include, but are not limited to, lithium
ion secondary battery packs for power storage.
-20-
The structure of middle- or large-sized battery packs using a secondary battery
as a unit cell and a fabrication method thereof are well-known in the art and a detailed
explanation thereof is thus omitted in this specification.
Now, the present invention will be described in more detail with reference to
5 the following examples. These examples are provided only to illustrate the present
invention and should not be construed as limiting the scope and spirit of the present
invention.

Graphite having a mean particle diameter of about 20 |xm as a core material
10 (A), pitch having a carbonization yield of 50% as a material for low crystalline carbon
(B), and lithium titanium oxide (I^TisO^) having a mean particle diameter of about
100 run as a hydrophilic material (C) were homogeneously mixed in a weight ratio of
I
A : B : C = 9 1 : 8 : 1 . This mixture was thermally-treated under a nitrogen atmosphere
at 1,200D for 2 hours in an electric furnace. During thermal treatment, the pitch was
15 softened and carbonized to form a composite with lithium titanium oxide and the
composite was coated on a graphite surface to produce an anode active material coated
i
with a carbon/lithium titanium oxide composite.
The anode active material, SBR and CMC were mixed in a weight ratio of
active material : SBR : CMC = 97.0 : 1.5 : 1.5 to prepare a slurry and the slurry was
-21-
*
applied to a Cu-foil to prepare an electrode. The electrode was roll-pressed to have a
porosity of about 23% and punched to fabricate a coin-type half cell. Li-metal was
used as a counter electrode of the cell and a coin-shaped battery was obtained using a
1M LiPFg electrolyte solution in a carbonate solvent.
5
An anode active material was produced and a coin-type half cell was fabricated
in the same manner as in Example 1, except that titanium oxide (T1O2) having a mean
particle diameter of about 100 nm was used, instead of lithium titanium oxide
(Li4Ti50i2).
10
An anode active material was produced and a coin-type half cell was fabricated
in the same manner as in Example 1, except that the hydrophilic material (C) was not
used.

15 An anode active material was produced by mixing graphite and lithium
titanium oxide in a weight ratio of 99:1 and a coin-type half cell was fabricated in the
same manner as in Example 1. . .. -
Experimental Example 1>
-22-
Electrolyte impregnation properties of the electrodes fabricated in accordance
with Examples 1 and 2 and Comparative Examples 1 to 3 were evaluated. The
electrode was roll-pressed to have a porosity of about 23% and a time taken for 1
microliter (|i£) of a 1M LiPF6 electrolyte solution in a carbonate solvent dropped on the
5 surface of the electrode to completely permeate into the surface was measured.
Results are shown in Table 1 below.

Ex. 1 Comp. Ex. 1 Comp. Ex. 2 Comp. Ex. 3
Imvp re&g nation 93 92 142 123
time (sec)
As can be seen from Table 1, the electrode using an anode active material
coated with a carbon/hydrophilic material composite according to Examples 1 and 2 of
10 the present invention exhibited considerably short electrolyte impregnation times, as
compared to the electrode using an anode active material coated with carbon alone
according to Comparative Example 1. The reason for this is that the surface of the
anode active material was coated with a hydrophilic material, thus enabling a highly
polar electrolyte to be rapidly permeated into particles.
15 In addition, as can be seen from Comparative Example 2, when the mixture of
graphite and a hydrophilic material was used, the hydrophilic material was not
-23-
uniformly distributed on the surface of the graphite and permeation time of an
electrolyte could not greatly reduced.
Experimental Example 2>
Charge/discharge properties were evaluated using the coin-type half cells
5 fabricated in accordance with Examples 1 and 2 and Comparative Examples 1 to 2.
Specifically, during charge, the cells were charged in a CC mode at a current density of
0.1C to 5 mV and then maintained in a CV mode at 5 mV, charging was completed
when current density reached 0.01C. During discharge, the cells were discharged in a
CC mode at a current density of 0.1 C to 1.5V. As a result, charge/discharge capacity
10 and efficiency of a first cycle were obtained. Then, charge/discharge was repeated 50
times under the same conditions as above, except that the current density was changed
to 0.5C. Results are shown in Table 2 below.

Ex. 1 Ex. 2 Comp. Ex. 1 Comp. Ex. 2
Charge 5 caFp acit3y 382.4 382.0 385.1 379.8
(mAh/g)
Discharge
capacity 353.7 354.1 356.6 350.9
(mAh/g)
Efficiency (%) 92^5 92A 92^6 92A
Capacity 90 89 78 83
maintenance
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I (%) after 50 I I I I I
charge/discharge
cycles
As can be seen from Table 2 above, the anode active materials coated with the
carbon/hydrophilic material composite according to Examples 1 and 2 of the present
invention exhibited high capacity maintenance after 50 charge/discharge cycles and
high efficiency, as compared to the anode active material according to Comparative
5 Example 1. The reason for this is that, when the hydrophilic material having the same
function as SEI forms a strong bond with a core material via carbon, removal of the SEI
layer in the repeated charge/discharge process is inhibited. Also, a material having
high charge/discharge voltage is coated, thereby preventing precipitation of lithium and
improving ion conductivity.
10 In addition, in Comparative Example 2 in which a simple mixture of graphite
and a hydrophilic material was used, the hydrophilic material was not homogeneously
distributed and was clustered, making the electrode non-uniform and decreasing
capacity maintenance after 50 charge/discharge cycles.
[INDUSTRIAL APPLICABILITY]
15 As apparent from the fore-going, the anode active material according to the
present invention greatly improves a battery fabrication process, minimizing
deterioration in electrical conductivity, considerably inhibits deterioration in battery
-25-
lifespan through a specific core/composite coating layer structure and minimizes
performance and safety problems associated with lithium precipitation through presence
of a material having a high oxidation-reduction potential on the surface of the active
material.
5 Although the preferred embodiments of the present invention have been
disclosed for illustrative purposes, those skilled in the art will appreciate that various
modifications, additions and substitutions are possible, without departing from the
scope and spirit of the invention as disclosed in the accompanying claims.
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[CLAIMS]
[Claim l ] An anode active material for secondary batteries, capable of
intercalating and deintercalating ions, the anode active material comprising:
a core comprising a crystalline carbon-based material; and
5 a composite coating layer comprising one or more materials selected from the
group consisting of low crystalline carbon and amorphous carbon, and a hydrophilic
material containing oxide capable of intercalating and deintercalating ions,
wherein the composite coating layer comprises:
a matrix comprising one component selected from (a) the one or more
10 materials selected from the group consisting of low crystalline carbon and amorphous
carbon and (b) the hydrophilic material containing oxide capable of intercalating and
deintercalating ions; and
a filler comprising the other component, incorporated in the matrix.
[Claim 2] The anode active material according to claim 1, wherein the
15 crystalline carbon-based material comprises one or more of graphite and low crystalline
carbon.
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[Claim 3] The anode active material according to claim 1, wherein the
hydrophilic material containing oxide capable of intercalating and deintercalating ions
is at least one selected from the group consisting of metal oxide and lithium metal
composite oxide.
5 [Claim 4] The anode active material according to claim 3, wherein the metal is
titanium.
[Claim 51 The anode active material according to claim 3, wherein the oxide is
represented by the following Formula 1.
Li4Ti5.xMxO12-y.2Ay (1)
10 wherein M is at least one selected from the group consisting of Mo, W, Zr, Hf,
Mn, Fe, Co, Ni, Zn, Al and Mg; A is at least one selected from the group consisting of
S, Se and Te; and 0< x< 1, 0< y< 2, and 0< z< 0.02.
[Claim 6] The anode active material according to claim 3, wherein the oxide is
at least one selected from the group consisting of Ti02, I^TisO^ and LiTi204-
15 [Claim 7] The anode active material according to claim 1, wherein the
composite coating layer has a structure in which the filler comprising the hydrophilic
material containing oxide capable of intercalating and deintercalating ions is
-28-
incorporated in the matrix comprising the one or more materials selected from the group
consisting of low crystalline carbon and amorphous carbon.
[Claim 8] The anode active material according to claim 1, wherein the
composite coating layer has a structure in which the filler comprising the one or more
5 materials selected from the group consisting of low crystalline carbon and amorphous
carbon is incorporated in the matrix comprising the hydrophilic material containing
oxide capable of intercalating and deintercalating ions,.
[Claim 9] The anode active material according to claim 1, wherein an amount of
the composite coating layer is 0.1 to 20% by weight, based on the total amount of the
10 anode active material.
[Claim 10] An anode mix comprising the anode active material according to any
one of claims 1 to 9.
[Claim 11 ] An anode for secondary batteries in which the anode mix according to
claim 10 is applied to a current collector.
15 [Claim 12] A secondary battery comprising the anode for secondary batteries
according to claim 11.
[Claim 13] The secondary battery according to claim 12, wherein the battery is a
lithium secondary battery.
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[Claim 14] A middle- or large-sized battery pack comprising the secondary
battery according to claim 13 as a unit cell.