KR20100026470A - Preparation of novel nanostructured titanium oxide nano-composite and its electrode application for charge storage devices - Google Patents

Abstract

The present invention relates to a titanium oxide material treatment method and a new structure of titanium oxide material for the application of electrode materials of charge storage devices such as lithium secondary batteries and hybrid capacitors of titanium oxide (TiO ₂ ) material, more specifically, the existing oxidation The present invention relates to the production of titanium oxide having a new nanostructure by forming a nanotube through acid and heat treatment of titanium or forming a nanocomposite with a carbon material and a metal material during acid and heat treatment.

By applying the newly prepared material of the present invention to a lithium secondary battery negative electrode material and a hybrid capacitor material, a lithium secondary battery having a high output and high energy electrode material by providing a negative electrode material having a higher capacity and higher speed characteristics than the conventional one; It is to realize a hybrid capacitor.

Description

Preparation of new nanocomposite titanium oxide nano-composite and its electrode application for charge storage devices}

The present invention provides a new nanostructured titanium oxide through the thermochemical treatment of titanium oxide and the reaction of carbon and dissimilar metals, thereby increasing the energy and output of lithium secondary batteries and hybrid capacitors with superior capacity and speed characteristics. It relates to a new electrode material that can be.

Lithium secondary batteries, which are currently increasing in maturity, are widely applied due to their larger capacity and higher output than secondary batteries such as NiMH and NiCd. The conventional lithium secondary battery is mainly a carbon-based material such as lithium transition metal oxide as a positive electrode and graphite as a negative electrode. However, batteries applied to hybrid electric vehicles (HEVs) and plug-in HEVs (PHEVs) require high energy, high output, and high safety. There is a problem that is difficult to realize.

Therefore, Ti oxide-based negative electrode material (Li _x Ti _y O _z , TiO ₂ ), which is currently being actively proposed as a negative electrode material for innovation and high output of lithium secondary battery, has an operating range of 1 V to 2 V. It is present in the spotlight as a material having excellent safety and speed characteristics due to its small structure change due to intercalation and the like. Examples of the Ti oxide-based anode material containing lithium include Li ₂ Ti ₃ O ₇ and Li ₄ Ti ₅ O ₁₂ Li ₄ Ti ₅ O ₁₂ is currently being applied as a high output cathode material such as HEV.

However, the lithium oxide containing Ti oxide has a theoretical capacity of 175 mAh / g and a flat surface at 1.5 V, so the high energy, which is the characteristic of medium and large power storage materials, and the internal capacity prediction through the voltage of the battery I have a problem. Therefore, TiO ₂ -based negative electrode materials containing no lithium are currently being actively studied, which have eight phases, and include anatase, bronze, TiO ₂ (B), and rutile TiO. _In the case of _two phases, the application to the cathode material is being actively performed, in particular, there is an advantage that changes in capacity, voltage, and speed characteristics occur through nano structure control. Such TiO ₂ -based anode material is still in the research stage, but has the advantages of high reversible capacity (theoretical capacity: 335 mAh / g, implementation capacity 270 mAh / g), high safety, improveable speed characteristics and cycle characteristics. It is expected to solve the problem of poor safety and low volume per volume of carbon-based negative electrode materials.

Recently, research on TiO ₂ based anode materials has been actively studied, and research through particle control of nanoparticles and particle size is the most active. In the case of TiO ₂ particles using this nanotechnology, the capacity is increased to around 300 mAh / g, and the capacity expression potential is inclined from 2 V to 1 V. It is reported in the literature as having the advantage of facilitating dose prediction. However, TiO ₂ -based negative electrode materials have poor cycle characteristics and poor speed characteristics, and need improvement.

The present invention provides a new nanostructured titanium oxide through the thermochemical treatment of titanium oxide and the reaction of carbon and dissimilar metals, thereby increasing the energy and output of lithium secondary batteries and hybrid capacitors with superior capacity and speed characteristics. The purpose is to provide a new electrode material that can be.

Another object of the present invention is to provide a lithium ion battery and a hybrid capacitor, which are charge storage devices having better energy, output, and safety than existing ones, based on newly manufactured electrode materials.

The present invention relates to a method for synthesizing various types of nanostructures by reacting a titanium oxide material with a metal salt or carbon powder under a high concentration of basic solution, and a titanium oxide nanocomposite synthesized through such a method.

The present invention solves the disadvantages of the conventional titanium oxide-based negative electrode material by producing a titanium oxide material treatment method and a new structure of titanium oxide material to provide a high cycle characteristics, high capacity, high speed characteristics and excellent safety material There is.

In addition, the present invention has the effect of improving the lithium ion battery and the hybrid capacitor, which is a charge storage device with superior energy, output, and safety than the existing based on the newly manufactured electrode material.

The present invention relates to a method for synthesizing various types of nanostructures by reacting a titanium oxide material with a metal salt or carbon material under a high concentration of basic solution, and to a titanium oxide nanocomposite synthesized through such a method.

The present invention is a mixture of a salt or oxide of one or two or more metals selected from tin (Sn), zinc (Zn), nickel (Ni), cobalt (Co) and silicon (Si), or a mixture of carbon powder and titanium oxide. 1 step of stirring the mixed solution in a basic solution at room temperature; Reacting the stirred mixed solution in an autoclave at 100-200 ° C .; And filtering the reactants, washing with 0.01 to 0.1 M hydrochloric acid, and drying to obtain titanium oxide nanocomposites. It relates to a titanium oxide nanocomposite manufacturing method comprising a.

More particularly, the present invention relates to a titanium oxide nanocomposite manufacturing method characterized in that the basic solution is one or two or more mixed solutions selected from sodium hydroxide, potassium hydroxide, lithium hydroxide and magnesium hydroxide solution.

Titanium oxide and activated carbon / minerals are added together in a 1-20 M sodium hydroxide solution, stirred at room temperature for 30 minutes to 5 hours, and placed in an autoclave at a temperature between 100 and 200 ° C for 1 to 10 days. After maintaining in the filter, it is washed with 0.01 ~ 0.1 M hydrochloric acid and dried to prepare it. Potassium hydroxide, lithium hydroxide and magnesium hydroxide solutions may also be used instead of the sodium hydroxide solution.

The material produced in this way has a pore size of about 5 to 50 nm and a surface area of about 50 to 500 m ² / g. In this case, when the reaction of changing the morphology of titanium oxide occurs, the addition of carbon is mixed with the carbon to nano size, thereby increasing the conductivity and stability of the structure.

The formation rate of the nanocomposite of carbon and titanium oxide is about 1 to 50% by weight of carbon, and more preferably 5 to 20% by weight of carbon.

In another aspect, the present invention relates to a titanium oxide nanocomposite manufacturing method characterized in that the particle size of the particle is 0.01 ~ 100 ㎛.

More specifically, the present invention relates to a titanium oxide nanocomposite manufacturing method characterized in that the carbon powder is one or a mixture of two selected from activated carbon or carbon black.

Types of titanium oxide used herein include inexpensive pigment-based pigments and the like, and particles having a particle size of 0.01 to 100 μm may be used. More preferably, a size of 0.5 to 5 μm is preferred. In addition, various kinds of carbons such as activated carbon, ketjenblack, denka black, and super-p such as carbon black can be used. Do.

Examples of the inorganic materials that can be used include materials such as salts of Zn-based salts, Sn-based metals, Co, Ni, and transition metals, and doses of these materials can be expected.

Titanium / carbon or titanium / inorganic nanocomposites produced in this way has the following characteristics. First, it has a high reversible charge and discharge capacity (about 180 mAh / g) compared to the conventional titanium, and even after 100 cycles (charge), the capacity is maintained to be higher than 99% compared to the initial capacity. In addition, as described above, it is possible to express a capacity of about 3 times at 10C as compared with a material prepared by reacting only titanium oxide or titanium oxide that has not been treated with a rate characteristic. This is because it is basically manufactured in the form of a transition metal oxide or a carbon material and a nanocomposite having excellent electron conductivity compared to TiO ₂ , which has a significantly lower electron conductivity.

In addition, the material produced by the reaction has a structure of various forms, it has a structure such as nanotube form, spherical form, preferably the spherical form is excellent in many properties.

The present invention relates to salts or oxides of one or two or more metals selected from tin (Sn), zinc (Zn), nickel (Ni), cobalt (Co), and silicon (Si) based on 100 parts by weight of titanium oxide, or carbon powder. It relates to a titanium oxide nanocomposite comprising a mixture of 1 to 50 parts by weight.

More particularly, the present invention relates to a titanium oxide nanocomposite, wherein the titanium oxide has a particle size of 0.01 to 100 μm.

The present invention relates to a lithium ion secondary battery comprising a negative electrode including the titanium oxide nanocomposite.

In addition, the present invention relates to a hybrid capacitor comprising a cathode including the titanium oxide nanocomposite.

Titanium oxide nanocomposites prepared by the present invention have a higher capacity, higher speed characteristics, and higher cycle characteristics than conventional lithium ion battery anode materials when applied to the battery, and thus have high energy density, high output, and lifetime. A battery having excellent safety and safety can be manufactured.

Hereinafter, the present invention will be described in more detail based on the following examples, but the present invention is not limited to the examples.

Example  One. TiO ₂ / Carbon Titanium Oxide Nanocomposites

95 g of titanium oxide material and 5 g of activated carbon having a surface area of 100 m ² / g were added to 400 g of 10 M sodium hydroxide solution, stirred at room temperature for about 2 hours, and placed in an autoclave at a temperature of 100 ° C. After maintaining for 5 days, it was filtered and washed sufficiently with 0.05 M hydrochloric acid and dried to prepare a titanium oxide nanocomposite.

Example  2. TiO ₂ Of ZnCl ₂  Titanium Oxide Nanocomposites

Titanium oxide nanocomposites were prepared in the same manner by adding 5 g of ZnCl ₂ material instead of the activated carbon used in Example 1.

Comparative example  One. TiO ₂  Titanium oxide

Titanium oxide that was not nanonized was prepared.

Comparative example  2. TiO ₂  Titanium Oxide Nanocomposites

100 g of titanium oxide was added to 400 g of 10 M sodium hydroxide solution, stirred at room temperature for 2 hours, and placed in an autoclave at 100 ° C. for 5 days, filtered and filtered. It was sufficiently washed and dried to prepare a titanium oxide nanocomposite.

Production Example . Using titanium oxide nanocomposites Of lithium ion battery  Produce

Examples 1 and 2 and Comparative Examples 1 and 2 and the material and the binder PVDF (Polyvinylidene Fluoride), the conductive agent is mixed with carbon black (super p) in a ratio of 90: 5: 5 and coated with an aluminum current collector Then, it was dried and roll press (roll press) to produce a coin cell using an electrode prepared.

The electrolyte used here was 1 M LiPF ₆ EC / DMC.

Test Example  1. Measurement of Structural Characteristics of Titanium Oxide Nanocomposites

The pore sizes and surface areas of Examples 1 and 2 and Comparative Examples 1 and 2 were measured, respectively.

The pore size was measured by BJH adsorption method using nitrogen adsorption method, and the surface area was measured by BET (Brunauer, Emmmett, Teller) method. The results are shown in Table 1 below.

Structure and cathode properties Pore size (nm) Surface area (m ² / g) Reversible Capacity (mAh / g) Cycle preservation (100 cycles) Speed characteristic (% / 10 C) Example 1 10 103 175 99 60 Example 2 20 90 150 96 43 Comparative Example 1 5 250 100 30 10 Comparative Example 2 10 87 155 98 20

The pore size is not nano titanium oxide Comparative Example 1 is 10 nm in Examples 1, 2 and Comparative Example 2 in which nano titanium oxide is introduced, the pore size is 10 nm or more, there is a difference in size. In addition, in Examples 1, 2 and Comparative Example 2 in which the nano titanium oxide was introduced at 250 m ² / g only in the case of Comparative Example 1, which is not nano titanium oxide, the surface area was 103 m ² / g. Big.

Test Example  2. Measurement of Cathodic Characteristics of Titanium Oxide Nanocomposites

The coin cell according to the manufacturing example was applied to a current of 10 C on the basis of 200 mAh / g to investigate the speed characteristics by using the degree of capacity reduction under high current, charging and discharging between 1 ~ 2.5 V voltage on the basis of 0.5 C The cycle characteristics were examined and the results are shown in Table 1 above. In addition, the reversible capacity was measured through charge and discharge, and the results are shown in Table 1 above.

The coin cells of Example 1 and Comparative Example 2 were applied with currents of about 0.1, 0.5, 1. 5. 10 C based on 200 mAh / g, and the speed characteristics were investigated using the degree of deterioration of the capacity under high current. , 6 is shown.

The reversible capacities of Example 1 and Comparative Example 2 were measured and shown in FIGS. 1 and 2. Charging is defined as the process of lowering the voltage (lithium storage), and discharging is defined as the direction of increasing the voltage (lithium emission). Particularly, in the third charging, the current is doubled and the charging capacity is decreased.

According to Table 1, it can be seen that the case of introducing nano titanium oxide is superior to the reversible capacity and cycle integrity of the case of using general titanium oxide.

In addition, in the case of Comparative Example 2 in which only nano titanium oxide was introduced, it can be seen that the speed characteristic is superior to the case in which the titanium oxide nanocomposite is introduced. In particular, when comparing Figs. 5 and 6, it can be seen that in the case of Example 1, the speed characteristic is much superior.

Figure 1 shows the characteristics of the lithium secondary battery electrode material of the anode made of titanium oxide nanocomposites prepared according to Example 1 of the present invention. The blue line represents the first charge and discharge, the red represents the second charge and discharge, and the black line represents the third charge and discharge.

Figure 2 shows the characteristics of the lithium secondary battery electrode material of the anode made of titanium oxide nanocomposites prepared according to Comparative Example 2 of the present invention. The blue line represents the first charge and discharge, the red represents the second charge and discharge, and the black line represents the third charge and discharge.

FIG. 3 shows a scanning electron microsopy of a titanium oxide nanocomposite prepared according to Example 1 of the present invention.

4 shows a transmission electron microscopy of the titanium oxide nanocomposites prepared according to Example 1 of the present invention.

Figure 5 shows the rate characteristics according to 0.1, 0.5, 1, 5, 10 C of the lithium secondary battery of the negative electrode prepared by the titanium oxide nanocomposite prepared according to Example 1 of the present invention. The red circle represents charge and the blue rectangle represents discharge.

Figure 6 shows the speed characteristics according to 0.1, 0.5, 1, 5, 10 C of the lithium secondary battery of the negative electrode made of titanium oxide nanocomposites prepared according to Comparative Example 2 of the present invention. The red circle represents charge and the blue rectangle represents discharge.

Claims (8)

A basic solution by mixing a salt or oxide of one or two or more metals selected from tin (Sn), zinc (Zn), nickel (Ni), cobalt (Co) and silicon (Si), or a mixture of carbon powders with titanium oxide 1 step of stirring the mixed solution at room temperature; Reacting the stirred mixed solution in an autoclave at 100-200 ° C .; And Filtering the reactants, washing with 0.01 to 0.1 M hydrochloric acid, and drying to obtain titanium oxide nanocomposites; Titanium oxide nanocomposite manufacturing method comprising a. The method of claim 1, The basic solution is a titanium oxide nanocomposite manufacturing method, characterized in that one or two or more mixed solutions selected from sodium hydroxide, potassium hydroxide, lithium hydroxide and magnesium hydroxide solution. The method of claim 1, The titanium oxide nanoparticles manufacturing method, characterized in that the particle size of 0.01 ~ 100 ㎛. The method of claim 1, The carbon powder is a titanium oxide nanocomposite manufacturing method, characterized in that the mixture of one or two selected from activated carbon or carbon black. Salts or oxides of one or two or more metals selected from tin (Sn), zinc (Zn), nickel (Ni), cobalt (Co) and silicon (Si) based on 100 parts by weight of titanium oxide, or a mixture of carbon powder 1 Titanium oxide nanocomposite comprising 50 parts by weight. The method of claim 5, wherein The titanium oxide nanoparticles nanocomposite, characterized in that the particle size of 0.01 ~ 100 ㎛. A lithium ion secondary battery comprising a negative electrode comprising the titanium oxide nanocomposite of claim 5 or 6. A hybrid capacitor comprising a cathode including the titanium oxide nanocomposite of claim 5 or 6.

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