Specification
[DESCRIPTION]
ANODE FOR SECONDARY BATTERY AND SECONDARY BATTERY
INCLUDING THE SAME
[TECHNICAL FIELD]
5 The present invention relates to an anode for secondary batteries in which an
anode mixture including an anode active material is coated on a current collector,
wherein the anode active material includes lithium titanium oxide (LTO) particles
provided on a surface thereof with a cross-linked polymer coating layer, wherein the
LTO particles with the cross-linked polymer coating layer formed thereon have a
10 porous structure formed therebetween, and a cross-linked polymer of the coating layer
is a phosphate-based compound and a secondary battery including the same.
[BACKGROUND ART]
As mobile device technology continues to develop and demand therefor
continues to increase, demand for secondary batteries as energy sources is rapidly
15 increasing. Among these secondary batteries, lithium secondary batteries, which
exhibit high energy density and operating potential, have long cycle lifespan, and have
a low self-discharge rate, are commercially available and widely used.
-1-
In addition, as recent interest in environmental problems is increasing,
research into electric vehicles (EVs), hybrid electric vehicles (HEVs), and the like that
can replace vehicles using fossil fuels, such as gasoline vehicles, diesel vehicles, and
the like, which are one of the main causes behind air pollution, is underway. As a
5 power source of EVs, HEVs, and the like, a nickel-metal hydride (Ni-MH) secondary
battery is mainly used. However, research into lithium secondary batteries having
high energy density, high discharge voltage, and high output stability is actively
carried out and some of the lithium secondary batteries are commercially available.
A lithium secondary battery has a structure in which an electrode assembly,
10 which includes: a cathode prepared by coating a cathode active material on a cathode
current collector; an anode prepared by coating an anode active material on an anode
current collector; and a porous separator disposed between the cathode and the anode,
is impregnated with a lithium salt-containing non-aqueous electrolyte.
Such lithium secondary batteries require a certain level or higher of porosity
15 of an electrode in consideration of ionic conductivity of active materials.
However, excess reduction in porosity of an electrode occurs in a process of
preparing an electrode slurry including an electrode active material and, consequently,
rapid decrease in C-rate may be caused.
-2-
Secondary batteries require a certain level or higher of C-rate according to
individual applications and, in particular, secondary batteries for power tools which
require high power or secondary batteries for EVs and HEVs require much higher Crate.
5 Therefore, there is an urgent need to develop a technology that may address
the above-described problems.
[DISCLOSURE]
[Technical Problem]
Therefore, the present invention has been made to solve the above problems
10 and other technical problems that have yet to be resolved.
As a result of a variety of extensive and intensive studies and experiments, the
inventors of the present invention confirmed that, when lithium titanium oxide, a
surface of which is coated with a phosphate-based compound as a crosslinked polymer,
is used as an anode active material, desired effects may be achieved, thus completing
15 the present invention.
In accordance with one aspect of the present invention, provided is an anode
for secondary batteries in which an anode mixture including an anode active material is
coated on a current collector, wherein the anode active material includes lithium
titanium oxide (LTO) particles provided on a surface thereof with a cross-linked
5 polymer coating layer, wherein the LTO particles with the cross-linked polymer
coating layer formed thereon retain a porous structure formed therebetween, and a
cross-linked polymer of the coating layer is a phosphate-based compound.
The anode according to the present invention uses LTO, a surface of which is
coated with a phosphate-based compound, as an anode active material and thus may
10 enhance power output characteristics and may also enhance lifespan due to a stabilized
electrode interface.
In particular, the LTO particles retain a predetermined porous structure even
though the coating layer is formed on the surfaces of the LTO particles, and thus, a
specific surface area of a layer of the anode active material may be increased and
15 connectivity among pores may be enhanced and, consequently, an impregnation ratio
of an electrolyte may be increased, which results in enhanced charge and discharge
characteristics.
-4-
That is, the phosphate-based compound has high reactivity with radicals and
thus is considered to enhance electrochemical stability of the anode active material
through improvement in progress of polymerization.
In particular, an LTO electrode may accelerate electrolyte decomposition
5 reaction (Ti4+ <—-> Ti3+) during charge and discharge and salt anions may accelerate
LTO catalytic and electrochemical reactions. In these aspects, it is considered that a
phosphate group may reduce liquid electrolyte decomposition by binding to Ti with
high stability and reduction reactivity through binding with anions and also serve to
suppress structural decomposition of the formed film.
10 In addition, the LTO used as an anode active material acts as a catalyst and
thus may accelerate cross-linking polymerization of the phosphate-based compound
and, accordingly, the above-described effects may be maximized.
In an embodiment, the phosphate-based compound may be at least one
material selected from the group consisting of a phosphate-based acrylate represented
15 by Formula 1 below, a pyrophosphate-based acrylate represented by Formula 2 below,
and a phosphate-based urethane acrylate.
O Ri O Rt O
I R2
R, O (1)
-5-
0 Rr Rt O
•|cii2aid]^o-p-o—* aid]^Y^
0 0 J" R?
J
Ri "o • (2)
In Formulas 1 and 2, R\ and R2 are each independently hydrogen, a methyl
group, or F, and n is an integer of 1 to 20.
Specifically, in Formula 1 and/or Formula 2, Ri may be hydrogen and n may
5 bel.
The anode may further include a multifunctional compound polymerizable
with the phosphate-based compound.
When the coating layer of the anode active material is formed together with
the multifunctional compound polymerizable with the phosphate-based compound,
10 various characteristics of a battery may be further enhanced.
That is, when the coating layer of the anode active material is formed by
cross-linking polymerization of the phosphate-based compound with high binding
affinity through a structure capable of satisfactorily coordinating lithium ions and the
multifunctional compound with excellent elasticity, electrochemical properties and
15 mechanical properties of each material may complement each other.
-6-
In an embodiment, the multifunctional compound may be at least one material
selected from the group consisting of a (meth)acrylic acid ester-based compound, an
unsaturated carbonic acid-based compound, a vinyl-based compound.
The (meth)acrylic acid ester-based compound is a (meth)acrylate-based
5 compound having at least two acrylate groups per molecule, and the (meth)acrylatebased
compound may be a monomer represented by Formula 3 below or an oligomer
thereof.
R 3
l m
° R5 R4 (3)
In Formula 3, R3, R4, and R5 are each independently hydrogen or a substituted
10 or unsubstituted C1-C4 alkyl group, and m is an integer of 1 to 20.
In addition, the (metha)acrylic acid ester-based compound may be at least one
material selected from the group consisting of diethylene glycol diacrylate
(Di(EG)DA), diethylene glycol dimethacrylate (Di(EG)DM), ethylene glycol
dimethacrylate (EGDM), dipropylene glycol diacrylate (Di(PG)DA), dipropylene
15 glycol dimethacrylate (Di(PG)DM), ethylene glycol divinyl ether (EGDVE),
ethoxylated(6) trimethylolpropane triacrylate (ETMPTA), diethylene glycol divinyl
ether (Di(EG)DVE), triethylene glycol dimethacrylate (Tri(EG)DM), dipentaerythritol
pentaacrylate (DPentA), trimethylolpropane triacrylate (TMPTA), trimethylolpropane
-7-
trimethacrylate (TMPTM), propoxylated(3) tri methyl olpropane triacrylate
(PO(3)TMPTA), propoxylated(6) trimethylolpropane triacrylate (PO(6)TMPTA), poly
(ethylene glycol) diacrylate (PA1), and poly(ethylene glycol) dimethacrylate, but
embodiments are not limited thereto.
5 The multifunctional compound may also form various types of copolymers
with the phosphate-based compound, e.g., a random copolymer, a block copolymer, a
graft copolymer, or the like.
The amount of the phosphate-based compound may be between 0.01 and 50
parts by weight, in particular between 1 and 30 parts by weight, based on 100 parts by
10 weight of the anode active material.
The coating layer of the phosphate-based compound may have a thickness of
0.001 p,m to 10 jam, in particular 0.1 Lim to 5 \im.
The porosity of the anode may be between 10 and 50%, in particular between
30 and 40%.
15 The term "porosity" used herein refers to a ratio of a hollow portion of a
porous material to a total volume of the porous material and is also referred to as
degree of pores or void fraction.
-8-
The anode for secondary batteries according to the present invention may be
manufactured using a method including: coating an anode slurry including LTO as an
anode active material on a current collector and drying the coated current collector
(step (A)); forming a phosphate-based compound coating layer on surfaces of LTO
5 particles by impregnating the anode manufactured by step (A) with a solution in which
the phosphate-based compound is dissolved (step (B)); and polymerizing the
phosphate-based compound through thermal curing, photocuring by irradiation of
electron beams or gamma rays, or stabilization reaction at a temperature of 30°C to
80°C (step (C)).
10 In step (B), the amount of the phosphate-based compound may be 0.1 wt% to
30 wt% based on a weight of a solvent.
When the amount of the phosphate-based compound is less than 0.1 wt%
based on the weight of the solvent, it is difficult to form the coating layer. On the
other hand, when the amount of the phosphate-based compound exceeds 30 wt% based
15 on the weight of the solvent, a transfer rate of lithium ions may decrease and thus
battery performance may be deteriorated. This is equally applied to a case in which
the multifunctional compound is added to the phosphate-based compound. That is, a
total amount (weight) of the phosphate-based compound and the multifunctional
compound may be between 0.1 and 30 wt%, in particular between 1 to 20 wt%, based
20 on the weight of the solvent.
-9-
The multifunctional compound polymerizable with the phosphate-based
compound may be included in the solution of step (B) in an amount of 0.1 wt% to 10
wt%, in particular 0.1 wt% to 0.5 wt%, based on the weight of the solvent. When the
amount of the multifunctional compound is too low, effects thereof are insufficient.
5 On the other hand, when the amount of the multifunctional compound is too great,
polymerization with the phosphate-based compound may be difficult to implement.
The solution in which the phosphate-based compound is dissolved may
include a polymerization initiator, an electrolyte solution (plasticizer), and a lithium
salt.
10 Examples of the polymerization initiator include, without being limited to,
azo-based compounds such as 2,2-azobis(2-cyanobutane), 2,2-
azobis(methylbutyronitrile), 2,2'-azoisobutyronitrile (AIBN), and azobisdimethylvaleronitrile(
AMVN), peroxy-based compounds such as benzoyl peroxide, acetyl
peroxide, dilauryl peroxide, di-tert-butyl peroxide, cumyl hydroperoxide, and
15 hydrogen peroxide, and hydroperoxides. In particular, the polymerization initiator
may be AIBN, 2,2'-azobis(2,4-dimethyl valeronitrile) (V65), di-(4-
tertbutylcyclohexyl)-peroxydicarbonate (DBC), or the like.
The polymerization initiator decomposes at a temperature of 40°C to 80°C to
form a radical and may react with monomers by free radical polymerization. In
-10-
general, free radical polymerization is implemented through initiation reaction
whereby highly reactive molecules or active sites are temporarily formed, propagation
reaction whereby monomers are added to active chain ends and thus active sites are
formed again at the chain ends, chain transfer reaction whereby active sites are
5 transferred to other molecules, and termination reaction whereby an active chain center
is destroyed. In addition, polymerization may also be implemented without using a
polymerization initiator.
The electrolyte solution also serves as a plasticizer. For example, the
electrolyte solution may be an aprotic organic solvent such as N-methyl-2-
10 pyrrolidinone, propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate
(BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate
(EMC), gamma butyrolactone, 1,2-dimethoxy ethane, tetrahydroxy franc, 2-methyl
tetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide,
dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid
15 triester, trimethoxy methane, dioxolane derivatives, sulfolane, methyl sulfolane, 1,3-
dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran
derivatives, ether, methyl propionate, or ethyl propionate. The electrolyte solution
may be used alone or in combination of at least two thereof.
The lithium salt is a material that is readily soluble in a non-aqueous
20 electrolyte and thus disintegrates into lithium ions. Examples thereof include LiCl,
-11-
LiBr, Lil, LiC104, LiBF4, LiBi0Cii0, LiPF6, LiCF3S03, LiCF3C02, LiAsF6, LiSbF6,
LiAlCi4, CH3S03Li, CF3S03Li, (CF3S02)2NLi, chloroborane lithium, lower aliphatic
carbonic acid lithium, lithium tetraphenyl borate, and imide. These lithium salts may
be used alone or at least two thereof may be used in combination.
5 The lithium salt may be included in an amount of 0.01 wt% to 30 wt%, in
particular 0.1 wt% to 20 wt%, based on total solids.
In addition, in order to improve charge/discharge characteristics and flame
retardancy, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether,
ethylenediamine, n-glyme, hexaphosphoric triamide, nitrobenzene derivatives, sulfur,
10 quinone imine dyes, N-substituted oxazolidinone, N,N-substituted imidazolidine,
ethylene glycol dialkyl ether, ammonium salts, pyrrole, 2-methoxy ethanol, aluminum
trichloride, or the like may be added to the electrolyte. In some cases, in order to
impart incombustibility, the electrolyte may further include a halogen-containing
solvent such as carbon tetrachloride, ethylene trifluoride, or the like. In addition, in
15 order to improve high-temperature storage characteristics, the electrolyte may further
include carbon dioxide gas.
In another embodiment, the anode for secondary batteries according to the
present invention may be manufactured using a method including coating an anode
slurry including LTO as an anode active material and the phosphate-based compound
-12-
on a current collector and drying the coated current collector (step (a)) and
polymerizing the phosphate-based compound by performing thermal curing,
photocuring by irradiation of electron beams or gamma rays, or stabilization reaction at
a temperature of 30°C to 80°C on the anode fabricated in step (a).
5 The present invention also provides a secondary battery including the anode
for secondary batteries. The secondary battery is manufactured so as to have a
structure in which an electrolyte is included in an electrode assembly including a
cathode, an anode, and a separator disposed between the cathode and the anode.
The cathode may for example be manufactured by coating a mixture of a
10 cathode active material, a conductive material, and a binder on a cathode current
collector and drying and pressing the coated cathode current collector. As desired,
the mixture may further include a filler.
The cathode current collector is generally fabricated to a thickness of 3 to 500
pm. The cathode current collector is not particularly limited so long as it does not
15 cause chemical changes in the fabricated lithium secondary battery and has high
conductivity. For example, the cathode current collector may be made of stainless
steel, aluminum, nickel, titanium, sintered carbon, aluminum or stainless steel surfacetreated
with carbon, nickel, titanium, or silver, or the like. The cathode current
collector may have fine irregularities at a surface thereof to increase adhesion between
-13-
the cathode active material and the cathode current collector. In addition, the cathode
current collector may be used in any of various forms including films, sheets, foils,
nets, porous structures, foams, and non-woven fabrics.
Examples of the cathode active material include, without being limited to,
5 layered compounds such as lithium cobalt oxide (UC0O2) and lithium nickel oxide
(LiNiCh) or compounds substituted with one or more transition metals; lithium
manganese oxides represented by Lii+xMn2-x04 where 03,
LiMn203, and LiMnC>2; lithium copper oxide (L12CUO2); vanadium oxides such as
L1V3O8, Li"V*304, V2O5, and CU2V2O7; Ni-site type lithium nickel oxides having the
10 formula LiNii.xMx02 where M=Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and 0.01
Anode Fabrication
Li1.33Ti1.67O4 as an anode active material, Denka black as a conductive
material, and PVdF as a binder were added to NMP and mixed therein in a weight ratio
15 of 95:2.5:2.5 to prepare an anode mixture. Subsequently, the anode mixture was
coated to a thickness of 200 |im on a Cu foil having a thickness of 20 \im and rolled
and dried, thereby completing fabrication of an anode.
-19-
The fabricated anode was impregnated in a coating solution prepared by
dissolving phosphate-based acrylate represented by Formula a below as a phosphatebased
material in DMC as a solvent in an amount of 10 wt% based on a weight of the
solvent for 30 minutes to form a coating layer thereon, and the resulting structure was
5 irradiated with electron beams to obtain an anode provided thereon with the coating
layer formed of the phosphate-based compound.
Manufacture of Battery
LiNio.5Mn1.5O4 as a cathode active material, Denka black as a conductive
10 material, and PVdF as a binder were added to NMP and mixed therein in a weight ratio
of 95:2.5:2.5 to prepare a cathode mixture, and the cathode mixture was coated on an
Al foil having a thickness of 20 um and rolled and dried, thereby completing
fabrication of a cathode.
Subsequently, a polyethylene film (Celgard®, thickness: 20 urn) as a
15 separator was interposed between the fabricated anode and cathode, and a liquid
electrolyte containing 1M LiPFg dissolved in EC/EMC (=1/2 (vol%)) was injected
thereinto, thereby completing manufacture of a pouch battery.
-20-
A pouch battery was manufactured in the same manner as in Example 1,
except that the pyrophosphate-based acrylate of Formula 2 where Ri is H and n is 1
was used as a phosphate-based material.
5
A pouch battery was manufactured in the same manner as in Example 1,
except that dipentaerythritol pentaacrylate (DPentA) as a multifunctional compound
was further added to the solution containing the phosphate-based material in an
amount of 0.2 wt% based on the weight of the solvent.
10
A pouch battery was manufactured in the same manner as in Example 2,
except that DPentA as a multifunctional compound was further added to the solution
containing the phosphate-based material in an amount of 0.2 wt% based on the weight
of the solvent.
15
Fabrication of Anode
-21-
Li1.33Ti1.67O4 as an anode active material, Denka black as a conductive
material, and PVdF as a binder were added to NMP and mixed therein in a weight ratio
of 95:2.5:2.5 to prepare an anode mixture. Subsequently, the anode mixture was
coated to a thickness of 200 (am on a Cu foil having a thickness of 20 urn and rolled
5 and dried, thereby completing fabrication of an anode.
The fabricated anode was impregnated in a coating solution prepared by
dissolving phosphate-based acrylate represented by Formula a below as a phosphatebased
material in DMC as a solvent in an amount of 0.2 wt% based on a weight of the
solvent for 30 minutes to form a coating layer thereon, and the resulting structure was
10 irradiated with electron beams to obtain an anode provided thereon with the coating
layer formed of the phosphate-based compound.
/" G >"'•'-..•.
(a)
Manufacture of Battery
15 LiNio.5Mni.5O4 as a cathode active material, Denka black as a conductive
material, and PVdF as a binder were added to NMP and mixed therein in a weight ratio
-22-
of 95:2.5:2.5 to prepare a cathode mixture, and the cathode mixture was coated on an
Al foil having a thickness of 20 um and rolled and dried, thereby completing
fabrication of a cathode.
Subsequently, a polyethylene film (Celgard®, thickness: 20 um) as a
5 separator was interposed between the fabricated anode and cathode, and a liquid
electrolyte containing 1M LiPFg dissolved in EC/EMC (=1/2 (vol%)) was injected
thereinto, thereby completing manufacture of a pouch battery.
A pouch battery was manufactured in the same manner as in Example 5,
10 except that DPentA as a multifunctional compound was further added to the solution
containing the phosphate-based material in an amount of 0.2 wt% based on the weight
of the solvent.
A pouch battery was manufactured in the same manner as in Example 1,
15 except that the phosphate-based acrylate was not added to the fabricated anode.
-23-
A 2016 coin cell was manufactured in the same manner as in Example 1,
except that a coating solution, prepared by adding the compound of Formula a to the
solvent in an amount of 40 wt% based on the weight of the solvent, was used.
Experimental Example 1>
5 The batteries (design capacity: 10.2 mAh) manufactured according to
Examples 1 to 6 and Comparative Examples 1 and 2 were subjected to formation at
2.75 V, and C-rate charge/discharge cycles of each battery were performed at a voltage
of 2.75 V - 1.6 V and discharge capacity thereof was confirmed. Results are shown
in Table 1 below.
Example 2
Experimental Example 2>
5C/5C cycle characteristics of the batteries of Examples 1 and 3 and
Comparative Examples 1 and 2 were measured during charging and discharging in a
chamber at a 45°C at a voltage of 1.6 V to 2.75 V and 5 C. Measurement results are
5 shown in FIG. 1.
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.
Claim
[Claim 1]
An anode for secondary batteries, comprising an anode mixture comprising an
anode active material, coated on a current collector, wherein the anode active material
5 comprises lithium titanium oxide (LTO) particles provided on surfaces thereof with a
cross-linked polymer coating layer, wherein the LTO particles with the cross-linked
polymer coating layer formed thereon retain a porous structure formed therebetween,
and a cross-linked polymer of the coating layer is a phosphate-based compound.
[Claim 2]
10 The anode according to claim 1, wherein the phosphate-based compound is at
least one material selected from the group consisting of a phosphate-based acrylate
represented by Formula 1 below, a pyrophosphate-based acrylate represented by
Formula 2 below, and a phosphate-based urethane acrylate:
O Ri O R, O
^V^JOCH CHQ- O - P- O - JCH2CH OJ^f
R3 o " R2
RI O
(1)
-26-
O Ri
OCHCHj O - P -O —P-Q
Ri 0
«i o (2)
wherein Ri and R2 are each independently hydrogen, a methyl group, or F,
and n is an integer of 1 to 20.
[Claim 3]
The anode according to claim 1, further comprising a multifunctional
compound polymerizable with the phosphate-based compound.
aim 4]
The anode according to claim 3, wherein the multifunctional compound is at
least one material selected from the group consisting of a (meth)acrylic acid ester-
10 based compound, an unsaturated carbonic acid-based compound, and a vinyl-based
compound.
[Claim 5]
The anode according to claim 4, wherein the (meth)acrylic acid ester-based
compound is a (meth)acrylate-based compound having at least two acrylate groups per
15 molecule.
-27-
aim
The anode according to claim 5, wherein the (meth) aery late-based compound
is a monomer represented by Formula 3 below or an oligomer thereof:
Rt
U R5 R* (3)
wherein R3, R4, and R5 are each independently hydrogen or a substituted or
unsubstituted C1-C4 alkyl group, and m is an integer of 1 to 20.
aim II
The anode according to claim 5, wherein the (meth)acrylic acid ester-based
compound is at least one material selected from the group consisting of diethylene
10 glycol diacrylate (Di(EG)DA), diethylene glycol dimethacrylate (Di(EG)DM),
ethylene glycol dimethacrylate (EGDM), dipropylene diacrylate (Di(PG)DA),
dipropylene glycol dimethacrylate (Di(PG)DM), ethylene glycol divinyl ether
(EGDVE), ethoxylated(6) trimethylolpropane triacrylate (ETMPTA), diethylene glycol
divinyl ether (Di(EG)DVE), triethylene glycol dimethacrylate (Tri(EG)DM),
15 dipentaerythritol pentaacrylate (DPentA), trimethylolpropane tnacrylate (TMPTA),
trimethylolpropane trimethacrylate (TMPTM), propoxylated(3) trimethylolpropane
triacrylate (PO(3)TMPTA), propoxylated(6) trimethylolpropane triacrylate
-28-
(PO(6)TMPTA), poly(ethylene glycol) diacrylate (PAl), and poly(ethylene glycol)
dimethacrylate.
[Claim 8]
The anode according to claim 1, wherein an amount of the phosphate-based
5 compound is 0.01 parts by weight to 50 parts by weight based on 100 parts by weight
of the anode active material.
[Claim 9]
The anode according to claim 1, wherein the cross-linked polymer coating
layer formed of the phosphate-based compound has a thickness of 0.001 um to 10 urn.
10 [Claim 10]
The anode according to claim 1, wherein the anode has a porosity of 10% to
50%
[Claim 11]
A method of manufacturing the anode for secondary batteries according to
15 claim 1, the method comprising:
coating an anode slurry comprising lithium titanium oxide (LTO) as an anode
active material on a current collector and drying the coated current collector;
-29-
forming a phosphate-based compound coating layer on surfaces of LTO
particles by impregnating the anode manufactured by the above step with a solution in
which the phosphate-based compound is dissolved; and
polymerizing the phosphate-based compound through thermal curing,
5 photocuring by irradiation of electron beams or gamma rays, or stabilization reaction at
a temperature of 30°C to 80°C.
[Claim 12]
The method according to claim 11, wherein the phosphate-based compound is
included in an amount of 0.1 wt% to 30 wt% based on a weight of a solvent.
10 [Claim 13]
The method according to claim 11, wherein the solution comprises a
polymerization initiator, an electrolyte solution (plasticizer), and a lithium salt.
[Claim 14]
The method according to claim 13, wherein the lithium salt is included in an
15 amount of 1 wt% to 30 wt% based on a total weight of solids.
[Claim 15]
-30-
The method according to claim 11, wherein a multifunctional compound
polymerizable with the phosphate-based compound is included in the solution used in
the forming in an amount of 0.1 wt% to 10 wt% based on a weight of a solvent.
[Claim 16]
5 A method of manufacturing the anode for secondary batteries according to
claim 1, the method comprising:
coating an anode slurry comprising lithium titanium oxide (LTO) as an anode
active material and the phosphate-based compound on a current collector and drying
the coated current collector; and
10 polymerizing the phosphate-based compound by performing thermal curing,
photocuring by irradiation of electron beams or gamma rays, or stabilization reaction at
a temperature of 30°C to 80°C on the anode manufactured by the coating.
[Claim 17]
A secondary battery comprising the anode for secondary batteries according
15 to any one of claims 1 to 10.
[Claim 18]
The secondary battery according to claim 17, wherein the secondary battery is
a lithium secondary battery.
[Claim 19]
A battery module comprising the secondary battery according to claim 18 as a
5 unit battery.
[Claim 20]
A battery pack comprising the battery module according to claim 19.
[Claim 21]
A device comprising the battery pack according to claim 20.
10 [Claim22]
The device according to claim 21, wherein the device is an electric vehicle, a
hybrid electric vehicle, a plug-in hybrid electric vehicle, or a system for storing power.