KR101811131B1 - New cynoethyl guar gum, negative electrode and secondary battery using the same, and the prepareation method of the same - Google Patents

Abstract

The present invention relates to a novel cyanoethylguanamine and a cathode electrode of a secondary battery using the same as a binder, and a secondary battery thereof. The secondary battery according to the present invention can provide an eco-friendly effect while improving the battery efficiency.

Description

TECHNICAL FIELD [0001] The present invention relates to a novel cyanoethylguanamine, a negative electrode for a secondary battery using the same, a secondary battery including the same, and a method for manufacturing the negative electrode,

The present invention relates to a novel material usable as an anode binder for a secondary battery, and more particularly to a novel cyanoethylguanum, a method for producing the same, a secondary battery comprising the novel cyanoethylguanoside as a cathode binder, And a manufacturing method thereof.

With the recent development of electronic technology, the miniaturization of portable electronic devices has been advanced, and a power source used therefor is required to be small and lightweight, that is, to have a high energy density. BACKGROUND ART As a battery having a high energy density, a secondary battery represented by a lithium ion secondary battery is widely used. As the miniaturization of portable devices becomes more advanced, it is expected that the secondary battery further has higher energy density and improved durability.

In addition, from the viewpoint of global environmental problems and energy saving, an electric vehicle using a secondary battery and an engine as a power source of a hybrid vehicle secondary battery has been developed and put into practical use. A vehicle-mounted power source used as a power source for a hybrid car or an electric car is large and expensive and becomes a main component of a vehicle as compared with a secondary battery used as a power source for a small portable device, . In addition, since the region and season of use of the automobile are various, it is also required to maintain durability and performance at high temperature and low temperature. Also, in these automobiles, it is important to accumulate the braking energy at the time of braking in the battery in order to improve the fuel efficiency, and a high-speed charging is required for this. In order to improve the acceleration of an automobile, the ability to emit energy in a short period of time, that is, high output density is required. As described above, in the in-vehicle rechargeable battery, in addition to the performance required for the rechargeable battery for small portable devices, various performance enhancements including safety are required.

In order to obtain a secondary battery having such characteristics, various researches and developments have been made on each member constituting the secondary battery. The secondary battery is mainly composed of an anode, a cathode, a separator for sealing them, and an electrolyte. The positive electrode and the negative electrode are each formed by adhering a powdery active material to a collecting plate. In order to extract the performance of the active material as a battery performance, it is essential to improve the performance of the binder as an adhesive for these active materials.

Conventionally, a typical lithium secondary battery uses graphite as a negative electrode active material, charging and discharging proceed while repeating a process in which lithium ions in an anode are inserted into a negative electrode and desorbed. The theoretical capacity of the battery varies depending on the kind of the electrode active material, but the charging and discharging capacities decrease with the progress of the cycle.

This phenomenon is the biggest cause of the separation of the electrode active material or between the electrode active material and the current collector due to the change of the volume of the electrode caused by the progress of the charging and discharging of the battery, so that the active material fails to function. In addition, lithium ions inserted into the negative electrode may not be properly discharged during the insertion or desorption, and the active sites of the negative electrode may be reduced. As a result, the charge / discharge capacity and lifetime characteristics of the battery may decrease as the cycle progresses.

Particularly, in order to increase the discharge capacity, when a material such as silicon, tin, silicon-tin alloy having a large discharging capacity is mixed with natural graphite having a theoretical discharge capacity of 372 mAh / g is used, The volume expansion of the negative electrode material is remarkably increased. As a result, the negative electrode material is separated from the electrode material. As a result, the capacity of the battery is drastically lowered due to repeated cycles.

Therefore, it is possible to prevent separation between the electrode active material or between the electrode active material and the current collector during the production of the electrode with a strong adhesive force, and to control the volume expansion of the electrode active material generated during repetitive charging and discharging with strong physical properties, There is a great demand in the art for a study on a binder and an electrode material capable of improving the performance of the battery due to the above-mentioned problems.

Since polyvinylidene fluoride (PVdF), which is an organic solvent-based binder, does not satisfy the above requirements, recently, an aqueous binder such as styrene-butadiene rubber (SBR) And mixing with a thickener or the like has been proposed and is currently being used commercially. In the case of such a binder, it is environmentally friendly and has an advantage that the battery capacity can be increased by reducing the content of the binder.

However, in the case of conventional thickening agents such as carboxy methyl cellulose, the viscosity is high and stable. However, since it is difficult to increase the solid content of the electrode slurry, it lowers the processability of the cell. Further, There is a problem that a swelling phenomenon in which the electrode assembly expands upon standing at a high temperature due to the gas which is caused by the gas.

Accordingly, there is a high demand for a lithium secondary battery including an aqueous binder which improves various characteristics of the battery and improves the structural stability of the electrode and has excellent adhesion.

Patent Document 1: International Patent Application 2013/122352 A1 Patent Document 2: U.S. Published Patent Application No. US2009 / 0117473 A1

Disclosure of the Invention The present invention has been conceived in order to solve the above-mentioned problems, and it is an object of the present invention to provide a novel cyanoethylguanum which can be used as a binder having improved structural characteristics of the secondary battery, And a method thereof.

Another object of the present invention is to provide a negative electrode of a secondary battery using the novel cyanoethylguanoside as a binder and a process for producing the same.

It is another object of the present invention to provide a lithium secondary battery using the novel cyanoethylguanoside as a binder.

In order to achieve the above object, the novel cyanoethylguan black according to the present invention has the following formula (1).

Here, the binder for a negative electrode of a secondary battery according to the present invention preferably contains cyanoethylguanosine having the formula (1).

Here, it is preferable that the secondary battery according to the present invention is lithium secondary battery.

Here, the negative electrode active material of the lithium secondary battery according to the present invention is preferably lithium titanium oxide.

To achieve the second object, a secondary battery according to the present invention includes: an active material containing lithium titanium oxide; A binder comprising cyanoethylguanosine having the formula (1); And a conductive agent.

Here, the active material of the positive electrode of the secondary battery is preferably a lithium manganese-based positive electrode active material, a lithium cobalt-based positive electrode active material, or a lithium iron phosphate-based positive electrode active material.

      In order to achieve the third object, the present invention provides a process for preparing a novel cyanoethylguanosine having the above formula (1)

Dissolving the guar gum in water to provide a guar gum solution;

Adding acrylonitrile to the guar gum lysis solution to react; And

And washing the reactants from the reaction to separate the solids.

Here, it is preferable to further include a step of drying the solids after the step of separating the solids.

In order to accomplish the fourth object, the present invention provides a method for preparing a negative electrode for a secondary battery, comprising: preparing a binder by dissolving cyanooethylguanium having the formula 1 in water;

Mixing the lithium titanium oxide and the conductive agent with the binder; And providing the mixture on a current collector.

Here, it is preferable that the step of providing the mixture on the current collector is a step of coating the mixture on the current collector.

According to the present invention as described above, it is possible to provide an aqueous binder for a secondary battery that improves various characteristics of a battery, improves the structural stability of the electrode, and has excellent adhesion.

Further, according to the present invention, it is possible to provide an aqueous binder for a secondary battery excellent in environmental friendliness.

Further, according to the present invention, it is possible to provide a secondary battery including the binder for a secondary battery excellent in adhesion and environment friendliness, and having improved battery characteristics.

FIG. 1 shows FT-IR spectra of cyanoethylguanum prepared according to the present invention.
FIGS. 2A and 2B show the results of a charge / discharge test of a secondary battery using a cyanoethylguanoside prepared according to the present invention as a binder and a secondary battery using a guar gum as a binder as a control group.
FIGS. 3A and 3B show results of a cyclic voltammetry test of a secondary battery using a cyanoethylguanoside prepared according to the present invention as a binder and a secondary battery using a guar gum as a binder as a control group.
FIG. 4 is a graph showing a comparison result of impedance of a secondary battery using cyanoethylguanoside prepared according to the present invention as a binder and a secondary battery using a control group of guar gum as a binder.
FIGS. 5A and 5B show results of a cyclic voltammetry test of a secondary battery using a cyanoethylguanoside prepared according to the present invention as a binder and a secondary battery using a control group of guar gum as a binder.
FIG. 6 is a graph showing a comparison result of a secondary battery using cyanoethylguanoside as a binder and a secondary battery using a control group of guar gum as a binder according to the present invention.
FIG. 7 is a graph showing the results of a contact angle test for a secondary battery using a cyanoethylguanoside prepared according to the present invention as a binder and a secondary battery using a guar gum as a binder as a control group.
FIGS. 8A and 8B show contact angle images of a secondary battery using cyanoethylguanoside prepared according to the present invention as a binder and a secondary battery using a control group, guar gum, as a binder.
FIGS. 9A and 9B show comparison results of xps of the surface of a negative electrode of a secondary battery using a cyanoethylguanoside prepared according to the present invention as a binder and a secondary battery using a guar gum as a binder as a control group.
FIG. 10 is a graph showing the adhesive strength of a secondary battery using cyanoethylguanoside prepared according to the present invention as a binder and a secondary battery using a control group of guar gum as a binder.
11 is a graph showing the results of comparison of electrolyte impregnation rates of a secondary battery using cyanoethylguanoside as a binder and a secondary battery using a guar gum as a binder as a control.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited thereto.

The present invention relates to a novel cyanoethylguanosine having the following formula (I) and a process for producing the same.

[Chemical Formula 1]

Gura gum is a kind of food additive which is obtained by pulverizing seed-bearing part of soybean and guar or by extracting it with hot water or hot water. Its main component is polysaccharide. It is a white to yellowish white, almost odorless powder, widely used as an extender, a stabilizer, an emulsifier and the like. It is known to be harmless to the human body and environmentally friendly, as it is often used as a food additive.

The formula of guar gum is as follows.

The possibility of its use as a thickener due to its viscosity is also discussed.

By introducing a cyano group into the cyanoethylguan black and guar gum of the present invention, it is possible to improve the conductivity of the lithium ion and also impart the effect of thickening.

The method for producing cyanoethylguanum of the present invention is as follows.

First, guar gum is dissolved in water to provide guar gum solution. If the guar gum is dissolved in water, a further catalyst may be added. As the catalyst, basic catalysts such as sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia water, and magnesium hydroxide can be used. Preferably, a strong basic catalyst such as sodium hydroxide or potassium hydroxide can be used.

Next, acrylonitrile is added to the guar gum dissolution solution to react the acrylonitrile and guar gum.

Acrylonitrile has the following formula:

This reaction is represented by the following reaction formula.

[Reaction Scheme 1]

A cyanoethylguan black cyano group prepared by the reaction of guar gum and acrylonitrile is introduced.

When acrylonitrile is added, it is preferable to drop slowly into the reactor for a predetermined time in consideration of the reactivity thereof. Further, the temperature of the reactor is preferably kept within a range of 40 캜 to 80 캜. If the temperature of the reactor is too low, the yield is not good. If the temperature of the reactor is too high, undesired side reactions occur, making it difficult to obtain a desired reactant.

Then, the reaction product from the reaction is washed to separate the solid material to obtain the novel cyanoethylguanosulfate of the present invention.

Here, it is preferable that the reactant, solid matter, is washed with alcohol to remove impurities and unreacted residual acrylonitrile.

The washing may be carried out using an organic solvent. Examples of the organic solvent include acetone, alcohols, ethers, methylene chlorides, xylons, etc. Alcohols are preferably used.

After washing to remove impurities, the nose form can be filtered out and the separated solids can be dried to obtain a solid form of cyanoethylguanos.

The binder for a negative electrode of a secondary battery according to the present invention comprises cyanoethylguanosine having the above formula (1), and may further contain an additive such as a thickener.

A cyanoethylguanosiloxane having the formula (1) is dissolved in water to prepare a binder usable for an electrode of a secondary battery.

The present invention relates to a secondary battery having a cathode electrode comprising cyanoethylguanosine having the formula (1) as a binder.

According to an embodiment of the present invention, there is provided a method of preparing a negative electrode for a secondary battery, comprising: preparing a binder by dissolving cyanoethylguanate having the formula 1 in water;

Mixing the lithium titanium oxide and the conductive agent with the binder; And providing the mixture on a current collector.

Here, it is preferable that the step of providing the mixture on the current collector is a step of coating the mixture on the current collector.

Here, it is preferable that the secondary battery according to the present invention is lithium secondary battery.

A lithium secondary battery or a lithium ion battery (-Battery, Lithium-ion battery, or Li-ion battery) is a type of secondary battery, in which lithium ions move from a cathode to an anode during a discharge process. At the time of charging, lithium ions move from the anode to the cathode again and find their place. A lithium ion battery is different from a lithium battery, which is a primary cell that can not be charged and reused, and is different from a lithium ion polymer battery using a solid polymer as an electrolyte.

Lithium-ion batteries have high energy density and no memory effect, and they are widely used in portable electronic devices because of their small self-discharge even when not in use. In addition, the frequency of use is gradually increasing in the fields of automobiles, air systems, and automobiles by using high energy density characteristics. However, care should be taken in general lithium-ion batteries as they may explode if misused.

The lithium secondary battery according to the present invention can constitute an anode comprising an active material, a binder containing cyanoethylguanosine having the formula (1), and a conductive agent.

The negative electrode active material according to the present invention is not particularly limited and includes, for example, carbon and graphite materials such as natural graphite, artificial graphite, expanded graphite, carbon fiber, non-graphitizable carbon, carbon black, carbon nanotube, fullerene and activated carbon; Metals such as Al, Si, Sn, Ag, Bi, Mg, Zn, In, Ge, Pb, Pd, Pt and Ti which can be alloyed with lithium and compounds containing these elements; Complexes of metals and their compounds and carbon and graphite materials; Lithium-containing nitrides, and the like. Among them, a carbon-based material is more preferable, and as a non-limiting example, the carbon-based material may be at least one selected from the group consisting of graphite carbon, coke carbon and hard carbon.

Lithium titanium oxide can be preferably used.

The lithium titanium oxide that can be used in the present invention may be represented by the following formula (4)

Specifically, Li0.8Ti2.2O4, Li2.67Ti1.33O4, LiTi2O4, Li1.33Ti1.67O4, Li1.14Ti1.71O4, and the like can be used, but not limited thereto, and more specifically, It may be Li1.33Ti1.67O4 or LiTi2O4 having a spinel structure with less change and excellent reversibility.

In addition to lithium titanium oxide (LTO), the negative electrode active material may include, for example, carbon such as non-graphitized carbon or graphite carbon; B, P, Si, Group 1 of the periodic table, LixFe2O3 (0? X? 1), LixWO2 (0? X? 1), SnxMe1-xMe'yOz (Me: Mn, Fe, Pb, 2 < / RTI > group III element, halogen, 0 < x < Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; Metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, and Bi2O5; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials; Titanium oxide and the like may be used together.

The conductive material is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture including the anode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing a chemical change in the battery, and includes, for example, graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used. Concrete examples of commercially available conductive materials include acetylene black series such as Chevron Chemical Company, Denka Singapore Private Limited, Gulf Oil Company, etc.), Ketjenblack, EC (Armak Company), Vulcan XC-72 (Cabot Company), and Super P (Timcal).

The negative electrode binder is a component which assists in binding of the active material and the conductive agent to the binder and in binding to the current collector, and is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture including the negative electrode active material.

The negative electrode of the secondary battery of the present invention may be produced by adding a filler.

The filler is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery and is optionally used as a component for suppressing the expansion of the anode. Examples of the filler include olefin-based polymerizers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The negative electrode for a secondary battery can be formed by applying a mixture for the negative electrode on a current collector. The negative electrode may be prepared by applying a slurry prepared by mixing a negative electrode mixture including the negative active material as described above with a solvent such as NMP, applying the slurry on the negative electrode collector, followed by drying and rolling.

The negative electrode current collector is generally made to have a thickness of 3 to 500 mu m. Such an anode current collector is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, and examples of the anode current collector include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, a surface of copper or stainless steel A surface treated with carbon, nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. In addition, like the positive electrode collector, fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.

In the cathode active material according to an embodiment of the present invention, the anode active material is preferably a lithium manganese-based cathode active material, a lithium cobalt-based cathode active material, or a lithium iron phosphate-based cathode active material.

Hereinafter, the present invention will be described in further detail with reference to embodiments of the present invention.

{Example}

Example  One: Cyanoethyl Guar gum  Produce

120 mL of distilled water was prepared in the reactor, and 4 g of guar gum powder was added thereto and dissolved.

After the guar gum was completely dissolved, 1 g of 50% NaOH solution was added to the reactor and stirred.

Then, 1 g of acrylonitrile was slowly dropped into the reactor for about 30 minutes while maintaining the temperature at 50 캜. The reaction was allowed to proceed for 3 hours under nitrogen purge.

The reaction terminated compound was then washed with alcohol, unreacted acrylonitrile was removed, and the solid was separated by filtration.

The separated solids were then dried in an oven at 60 ° C.

Thus, cyanoethylguanum was prepared.

Comparative Example  One

The guar gum powder used in Example 1 was prepared.

Example  2: Cyanoethyl Guar gum  Manufacture of electrode used

The cyanoethylguanum prepared in Example 1 was dissolved in water to prepare a binder.

Next, 85% by weight of the LTO active material, 5% by weight of the binder and 10% by weight of the super P conductive agent were mixed for 1 hour at a speed of 320 rpm using a planetary ball mill.

The mixed electrode slurry was coated on a 20 탆 thick copper current collector using a coating machine and dried in an oven at 60 캜 for 30 minutes.

And dried in a vacuum oven at 70 캜 for one day to remove water from the electrode.

Thus, an LTO electrode having a loading value of 4.0 ± 0.1 mg / cm ² was prepared.

Comparative Example  2:

The LTO electrode was prepared in the same manner as in Example 2, except that a binder was prepared from guano powder instead of cyanoethylguanum.

{evaluation}

1. FT-IR measurement

The peak was confirmed by measuring the FT-IR of the cyanoethylguanum prepared according to Example 1 and the guar gum powder prepared according to Comparative Example 1.

As a result, in the case of cyanoethylguanoside prepared according to Example 1, the peak value was confirmed at the wavelengths of 2200 to 2250, thereby confirming that cyano group was generated. FIG. 1 shows this FT-IR measurement graph.

2. Charging and discharging  Test

Using the PNE solution equipment, charge and discharge tests were carried out with a constant current (CC) mode at a voltage range of 1V to 2.6V with 0.1C for the first two cycles and then 1C for 100 cycles. In addition, charge and discharge tests were carried out at various current rates from 0.1C to 20C for rate capability measurement.

The results are shown in Figs. 2A and 2B.

2A and 2B, the electrode (cyanoethylguanine binder) prepared according to Example 2 had better electrode capacity than the electrode (guar gum binder) prepared according to Comparative Example 2 , It showed good performance even at high C rate and showed about 40% performance improvement.

3. CV  And impedance measurement

(Cyclic Voltammetry, CV) of the electrode (guar gum binder) prepared according to Comparative Example 2 in the case of the electrode (cyanoethylguanine binder) prepared according to Example 2 is shown in FIG. 3A And Fig. 4 (impedance), respectively.

3A and 3B and FIG. 4, it can be seen that the electrode according to Example 2 has excellent electrochemical reactivity and electron transfer resistance due to the excellent ion conductivity of cyanoethylguanum.

4. Cyclic voltage injection test by scan speed

FIGS. 5A and 5B show results of a cyclic voltammetry test of the electrode (cyanoethylguanamine binder) prepared according to Example 2 and the electrode (guar gum binder) prepared according to Comparative Example 2 at different scan speeds , It can be confirmed that the electrode (cyanoethylguanine binder) prepared according to Example 2 has better electrochemical reactivity than the electrode (guar gum binder) prepared according to Comparative Example 2.

5. Randall - SEVIC  Evaluation of diffusion of lithium ion electrode by equation

The Randle-Sevik equations are:

I _p / m = 0.4463 F (F / RT) ^1/2 C _{Li ^{V 1/2 AD Li 1/}} 2

In this formula,

I _p / m = the peak current per unit mass

F = the Faraday`s constant

R = the gas constant

T = the absolute temperature

V = scan rate

A = the surface area of the electrode

C _Li = the initial concentration of Li-ion

D _Li = the diffusion coefficient

to be.

Referring to FIG. 6 and the above equation, the diffusion coefficient at the electrode of lithium ion was found to be 3.19E-08 cm ² / s for the electrode according to Example 2 and 1.03E-08 cm ^{2 /} / s.

Therefore, it can be seen that the degree of diffusion in the electrode according to the second embodiment is greater.

6 . Contact Angle Test

FIG. 7 shows the result of examining the wettability between the binder film and the electrolyte through the contact angle test, and FIGS. 8A and 8B show the wqjchrrkr image of the binder film after 10 seconds. Referring to FIG. 7, The wettability of the binder is more excellent.

7. XPS  Test

Figs. 9A and 9B show comparison results of xps of the surface of the cathode electrode, Fig. 10 shows the adhesive strength, and Fig. 11 shows the electrolyte impregnation rate.

With XPS, the exposure level of titanium on the LTO electrode surface can be checked. The smaller the binding, the greater the exposure of titanium and the lower the adhesion. Therefore, it can be seen that the adhesive force of the electrode according to Example 2 is reduced.

However, it is understood that the adhesive force is not an important factor in the LTO electrode, and that the electrode according to Example 2 having less adhesive force has better lithium mobility.

INDUSTRIAL APPLICABILITY As described above, the binder for a secondary battery according to the present invention has an effect of improving structural stability of the electrode while improving various characteristics of the battery.

In addition, the binder for a secondary battery according to the present invention has an excellent adhesive strength and an excellent eco-friendliness.

Further, according to the present invention, it is possible to provide a secondary battery including the binder for a secondary battery excellent in adhesion and environment friendliness, and having improved battery characteristics.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. And such applications and modifications are within the scope of the present invention.

The present invention, which can be applied to a lithium secondary battery, can be used in the battery industry.

Claims (10)

A novel cyanoethylguanamine having the following formula 1:
[Chemical Formula 1]

. Cyanoethylguanamine having the following formula 1:
[Chemical Formula 1]

Wherein the negative electrode binder is a negative electrode. 3. The method of claim 2,
Wherein the secondary battery is lithium secondary battery. The method of claim 3,
Wherein the negative electrode active material of the lithium secondary battery is lithium titanium oxide.
An active material containing lithium titanium oxide;
Cyanoethylguanosine having the following formula 1,
[Chemical Formula 1]

A binder; And
Conductive agent;
And a negative electrode including a negative electrode.
6. The method of claim 5,
Wherein the active material of the positive electrode of the secondary battery is a lithium manganese-based positive electrode active material, a lithium cobalt-based positive electrode active material, or a lithium iron phosphate-based positive electrode active material.
Dissolving the guar gum in water to provide a guar gum solution;
Adding acrylonitrile to the guar gum lysis solution to react; And
And washing the reaction product from the reaction to separate the solid material. The method for producing cyanoethylguanosine according to claim 1,
[Chemical Formula 1]

. 8. The method of claim 7,
Further comprising the step of drying the solid after the step of separating the solids. ≪ RTI ID = 0.0 > 11. < / RTI > Cyanoethylguanosine having the following formula 1,
[Chemical Formula 1]

In water to prepare a binder;
Mixing the lithium titanium oxide and the conductive agent with the binder to prepare a mixture; And
And providing the mixture on a current collector. ≪ Desc / Clms Page number 19 >
10. The method of claim 9,
Wherein the step of providing the mixture on the current collector is a step of coating the mixture on the current collector.

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