KR100893524B1 - Anode active material, method of preparing the same, anode and lithium battery containing the material - Google Patents

Abstract

The present invention represents a silicon peak having binding energy of 103 to 106 eV in the X-ray photoelectric spectrum and having a full width at half maximum (FWHM) of 1.6 to 2.4 eV, the atomic% calculated from the area of the peak. A silicon oxide-based composite anode active material including an amorphous silicon oxide represented by general formula SiO _x (0 <x <2) having a value of 10 or more is disclosed.

The negative electrode active material according to the present invention is a composite negative electrode active material containing amorphous silicon oxide of a novel structure obtained directly from a fired product of hydrogen silsesquioxane (HSQ). In addition, the negative electrode and the lithium battery including the composite negative electrode active material have excellent charge and discharge characteristics.

Lithium battery

Description

Anode active material, method of preparing the same, anode and lithium battery containing the material}

The present invention relates to a negative electrode active material, a method for manufacturing the same, and a negative electrode and a lithium battery employing the same, and more particularly, a negative electrode active material having a specific silicon peak in X-ray photoelectric experiments, a method for manufacturing the same, and a charge / discharge capacity and lifespan including the same. It relates to a negative electrode and a lithium battery with improved characteristics.

Nonaqueous electrolyte secondary batteries using lithium compounds as negative electrodes have high voltage and high energy density and have been the subject of many studies. Among them, lithium metal has been the subject of much research in the early days when lithium was attracting attention as a negative electrode material due to its rich battery capacity. However, when lithium metal is used as a negative electrode, a large amount of dendritic lithium precipitates on the surface of the lithium during charging, which may reduce charge and discharge efficiency, cause a short circuit with the positive electrode, and may cause heat or shock due to instability of lithium itself, ie, high reactivity. It is sensitive and has a risk of explosion, making it an obstacle to commercialization. The carbon-based negative electrode solves the problem of the conventional lithium metal. The carbon-based negative electrode is a so-called rocking-chair method in which a lithium ion present in an electrolyte solution does not use lithium metal and performs a redox reaction while intercalating and discharging between crystal surfaces of a carbon electrode during charging and discharging.

The carbon-based negative electrode contributed to the popularization of lithium batteries by solving various problems of lithium metal. However, as various portable devices have become smaller, lighter, and higher in performance, higher capacity of lithium secondary batteries has emerged as an important problem. Lithium batteries using carbon-based negative electrodes have inherently low battery capacity due to the porous structure of carbon. For example, even in the case of the most crystalline graphite, the theoretical capacity is about 372 mAh / g in the composition of LiC6. This is only about 10% of the theoretical capacity of lithium metal at 3860mAh / g. Therefore, despite the existing problems of the metal negative electrode, a study to improve the capacity of the battery by introducing a metal such as lithium to the negative electrode is being actively attempted.

Typically, a material capable of alloying with lithium such as Si, Sn, Al, etc. may be used as the negative electrode active material. However, materials capable of alloying with lithium, such as Si and Sn, are accompanied by volume expansion during the alloy reaction with lithium, generate an active material that is electrically isolated in the electrode, and intensify the decomposition reaction of the electrolyte by increasing the specific surface area. I have a problem.

In order to solve the problems caused by the use of such a metal material, a conventional technique using a metal oxide having a relatively low volume expansion ratio as a material of a negative electrode active material has been proposed.

Science, 276, 1395 (1997) has proposed amorphous Sn-based oxides, which actually showed excellent capacity retention characteristics by minimizing Sn size and preventing agglomeration of Sn that occurs during charging and discharging. However, Sn-based oxides have a problem in that a reaction between lithium and oxygen atoms inevitably occurs and an irreversible capacity exists.

In addition, Japanese Patent No. 2997741 obtained an electrode having a high capacity by using silicon oxide as a negative electrode material of a lithium ion secondary battery. However, also in this case, the irreversible capacity | capacitance at the time of initial charge / discharge was large, and the cycling characteristics were insufficient for practical use.

Therefore, there is still a need for the development of a negative electrode showing better charge and discharge characteristics by solving these problems with conventional negative electrode materials.

The first technical problem to be achieved by the present invention is to provide a silicon oxide-based composite anode active material having a specific silicon peak in the X-ray photoelectric experiment.

The second technical problem to be achieved by the present invention is to provide a negative electrode and a lithium battery including the negative electrode active material, the charge and discharge capacity and the capacity retention rate is improved.

The third technical problem to be achieved by the present invention is to provide a method of manufacturing the negative electrode active material.

The present invention to achieve the first technical problem,

In the X-ray photoelectric spectrum, a silicon peak having a binding energy of 103 to 106 eV and a full width at half maximum (FWHM) of 1.6 to 2.4 eV, and the atomic% calculated from the area of the peak is 10 or more. Provided is a silicon oxide-based composite anode active material including amorphous silicon oxide represented by general formula SiO _x (0 <x <2) having a value.

In addition, the present invention provides a negative electrode and a lithium battery employing the negative electrode active material in order to achieve the second technical problem. In addition, the present invention to achieve the third technical problem,

It provides a method for producing a silicon oxide-based composite negative electrode active material comprising the step of firing hydrogen silsesquioxane (hydrogen silsesquioxane, HSQ) in a temperature range of 900 to 1300 ℃ under an inert atmosphere.

The negative electrode active material according to the present invention is a composite negative electrode active material containing amorphous silicon oxide having a new structure, unlike a silicon oxide-based composite negative electrode active material obtained from a conventional silicon dioxide or the like. In addition, the negative electrode and the lithium battery including the composite negative electrode active material have excellent charge and discharge characteristics.

The negative electrode active material according to the present invention is a composite negative electrode active material containing amorphous silicon oxide of a novel structure obtained directly from a fired product of hydrogen silsesquioxane (HSQ). In addition, the negative electrode and the lithium battery including the composite negative electrode active material have excellent charge and discharge characteristics.

Hereinafter, the present invention will be described in more detail.

The silicon oxide-based negative active material of the present invention exhibits a silicon peak having a binding energy of 103 to 106 eV in the X-ray photoelectric spectrum and a full width at half maximum (FWHM) of 1.6 to 2.4, and an atom calculated from the area of the peak. % (atomic%) includes amorphous silicon oxide represented by the general formula SiO _x (0 <x <2) having a value of 10 or more.

As shown in FIG. 1, the amorphous silicon oxide shows an amorphous phase in which no crystalline peak is present in the X-ray diffraction experiment.

In addition, unlike SiO, which is a conventional silicon oxide, SiOx oxide according to an embodiment of the present invention has an atomic% (atomic%) of silicon having a high binding energy, for example, 105.4 eV, in the X-ray photoelectric spectrum. Exceeded%. The high content of silicon atoms having such a high binding energy value is considered to be due to the fact that the silicon oxide of the present invention includes a nanopore structure unlike a conventional silicon oxide. By such a nano-pore structure, the silicon oxide of the present invention may exhibit relatively excellent lithium storage / release characteristics compared to conventional general silicon oxides.

More preferably, the amorphous silicon oxide may have a silicon peak having a binding energy of 105 to 106 eV in the X-ray photoelectric spectrum and a full width at half maximum (FWHM) of 1.8 to 2.2.

More preferably, the amorphous silicon oxide is represented by the general formula SiO _x (1 <x <1.7). Further, it is more preferable that the atomic% calculated from the area of the silicon peak has a value of 8 or more, and most preferably has a value of 8% to 10.8%.

The amorphous silicon oxide may be prepared by calcining hydrogen silsesquioxane (HSQ).

Hydrogen silsesquioxane is a type of poly (silsesquioxane) (POSS) and is represented by the general formula HSiO _3/2 . The poly (silsesquioxane) has a cage structure, a network structure, or a mixed structure thereof before heat treatment, but may be converted into a network structure after heat treatment. Poly (silsesquioxane) is a low dielectric constant material, and when sol-gel method is used, it is also possible to manufacture mesoporous material having a certain size of micropores. come. However, the case of using the poly (silsesquioxane) as the material of the negative electrode active material has not been reported yet. In the present invention, a composite negative electrode active material comprising a new amorphous silicon oxide obtained directly by firing hydrogen (silsestuoxane) that does not contain a carbon atom as a kind of the poly (silsesquioxane) at a high temperature of 900 ℃ to provide.

Hydrogen silsesquioxane (HSQ) used in the production of the silicon oxide composite anode active material is preferably obtained by sol-gel reaction of a silane compound. The sol-gel reaction of the silane compound is a sol in which a low molecular weight silane compound is very stable through hydrolysis and condensation reaction under appropriate reaction conditions and a sol in which inorganic particles having a uniform structure are dispersed or the inorganic particles continue to grow to obtain a gel. Reaction. In the present invention, a sol of the silane compound are obtained hydrogen silsesquioxane having a formula HSO _3/2 by the reaction gel.

The silane compound used in the present invention is preferably a silicon oxide-based composite anode active material, characterized by the following formula (1):

<Formula 1>

HSi (R ₁ ) (R ₂ ) (R ₃ )

Wherein R, R _1, R ₂ and R ₃ is halogen, or substituted or unsubstituted hwandoen independently of each other C _{1 - 10} is an alkoxy group. Among these, trichlorosilane, trimethoxy silane, and triethoxysilane are especially preferable.

The substituent of the substituted alkoxy group include halogen, C _{1 - 5} alkyl, C _{2 - 5} alkenyl, C _{1 - 5} alkoxy group, etc. are preferred.

In the present invention, in the sol-gel reaction for producing hydrogen silsesquioxane (HSQ), by adding 10 to 60% by weight of the total amount of the mixture of the silane compound and the carbon-based material together with the silane compound Preference is given to the sol-gel reaction. When the carbonaceous material is added to the sol-gel reaction, a composite structure in which the carbonaceous material is included in hydrogen silsesquioxane can be obtained.

When calcining the hydrogen silsesquioxane having the complex structure, a silicon oxide-based composite anode active material having a structure additionally including carbon-based particles dispersed in amorphous silicon oxide may be obtained.

In the present invention, when firing the hydrogen silsesquioxane, it is preferable to add 10 to 90% by weight of the total amount of the mixture of the hydrogen silsesquioxane and the carbon precursor together with the hydrogen silsesquioxane. When the carbon precursor is mixed, a carbon-based coating layer may be formed on the surface of the amorphous silicon.

That is, a silicon oxide-based composite anode active material having a structure additionally including a carbon-based coating layer formed on the amorphous silicon oxide may be obtained. The carbon-based coating layer may be formed to cover the entire amorphous silicon oxide particles.

In addition, the present invention provides a negative electrode and a lithium battery employing the negative electrode active material in order to achieve the second technical problem. More specifically, the negative electrode of the present invention is characterized in that it is prepared including the porous negative electrode active material described above.

The electrode may be formed by, for example, molding a negative electrode mixture material containing the porous negative electrode active material and a binder into a predetermined shape, or manufactured by applying the negative electrode mixture material to a current collector such as copper foil.

More specifically, a negative electrode material composition is prepared and coated directly on a copper foil current collector, or the porous negative electrode active material film cast on a separate support and peeled from the support is laminated on the copper foil current collector to obtain a negative electrode plate. In addition, the negative electrode of this invention is not limited to the form enumerated above, The form other than the enumerated form is possible.

In order to increase the capacity of the battery, it is necessary to charge and discharge a large amount of current, and for this purpose, a material having low electrical resistance of the electrode is required. Therefore, in order to reduce the resistance of the electrode, the addition of various conductive materials is common, and mainly used conductive materials include carbon black and graphite fine particles.

The lithium battery of the present invention is characterized by being manufactured including the above negative electrode. The lithium battery of the present invention can be produced as follows.

First, a cathode active material composition is prepared by mixing a cathode active material, a conductive material, a binder, and a solvent. The positive electrode active material composition is directly coated on a metal current collector and dried to prepare a positive electrode plate. It is also possible to produce the positive electrode plate by casting the positive electrode active material composition on a separate support, and then laminating the film obtained by peeling from the support onto a metal current collector.

The positive electrode active material may be any lithium-containing metal oxide, as long as it is commonly used in the art, for example, LiCoO ₂ , LiMn _x O _2x , LiNi _{x -1} Mn _x O _2x (x = 1, 2), and the like _{Li 1 -x- y Co x Mn y} O 2 (0≤x≤0.5, 0≤y≤0.5) , and more particularly, _{LiMn 2 O 4, LiCoO 2,} LiNiO 2, LiFeO 2, V 2 Compounds capable of redox of lithium, such as O ₅ , TiS and MoS.

Carbon black is used as the conductive material, and vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, and polytetrafluoroethylene And a mixture thereof, a styrene butadiene rubber polymer, and a solvent such as N-methylpyrrolidone, acetone, water, and the like. At this time, the content of the positive electrode active material, the conductive material, the binder, and the solvent is at a level commonly used in lithium batteries.

As the separator, any one commonly used in lithium batteries can be used. In particular, it is preferable that it is low resistance with respect to the ion migration of electrolyte, and is excellent in electrolyte-moisture capability. More specifically, the material selected from glass fiber, polyester, teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), and combinations thereof may be nonwoven or woven. More specifically, a lithium ion battery uses a rollable separator made of a material such as polyethylene or polypropylene, and a lithium ion polymer battery uses a separator having excellent organic electrolyte impregnation ability. It can manufacture according to the following method.

That is, a separator composition is prepared by mixing a polymer resin, a filler, and a solvent, and the separator composition is directly coated and dried on an electrode to form a separator film, or the separator composition is cast and dried on a support, and then the support The separator film peeled off can be laminated on the electrode and formed.

The polymer resin is not particularly limited, and any material used for the binder of the electrode plate may be used. For example, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate and mixtures thereof can be used.

Examples of the electrolyte include propylene carbonate, ethylene carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, butylene carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, and dioxo Column, 4-methyldioxolane, N, N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, dimethyl carbonate LiPF ₆ , a solvent such as methyl ethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, ethyl propyl carbonate, dipropyl carbonate, dibutyl carbonate, diethylene glycol or dimethyl ether, or a mixed solvent thereof. LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , LiSbF ₆ , LiAlO ₄ , LiAlCl ₄ , Li N (C _x F _{2x +1} SO ₂ ) (C _y F _{2y +1} SO ₂ ) (where x and y are natural water), one or more electrolytes consisting of lithium salts such as LiCl and LiI, or mixtures of two or more thereof The separator may be disposed between the positive electrode plate and the negative electrode plate as described above to form a battery structure. The battery structure is wound or folded, placed in a cylindrical battery case or a square battery case, and then the organic electrolyte solution of the present invention is injected to complete a lithium ion battery.

In addition, after stacking the battery structure in a bi-cell structure, it is impregnated in an organic electrolyte, and the resultant is placed in a pouch and sealed to complete a lithium ion polymer battery.

In addition, the present invention provides a method for producing a negative electrode active material in order to achieve the third technical problem.

One aspect of the method for producing a negative electrode according to the present invention includes the step of firing hydrogen silsesquioxane (hydrogen silsesquioxane, HSQ) in a temperature range of 900 to 1300 ℃ under an inert atmosphere.

The hydrogen silsesquioxane (HSQ) preferably has at least one structure selected from the following Chemical Formula 2, Chemical Formula 3, or a complex structure thereof:

<Formula 2> <Formula 3>

Wherein R is hydrogen.

In addition, the hydrogen silsesquioxane is preferably obtained by sol-gel reaction of an silane compound represented by the following Chemical Formula 1 under an acid catalyst:

<Formula 1>

HSi (R ₁ ) (R ₂ ) (R ₃ )

Where

R _1, R ₂ and R ₃ are C ₁ to each other, independently, halogen, or substituted or unsubstituted _{- 10} is an alkoxy group. Among these, trichlorosilane, trimethoxy silane, and triethoxysilane are especially preferable. The substituent of the substituted alkoxy group include halogen, C _{1 - 5} alkyl, C _{2 - 5} alkenyl, C _{1 - 5} alkoxy group, etc. are preferred.

In one aspect of the production method in a sol-gel reaction for producing hydrogen silsesquioxane (HSQ), the carbon-based material together with the silane compound is 10 to 60 of the total amount of the mixture of the silane compound and the carbon-based material It is preferable to carry out a sol-gel reaction by adding weight%. If the content is less than 10, there is a problem that the mixing of the carbon-based material is meaningless because the carbon content is less, and if it is more than 60, there is a problem of a reduction in energy density due to the excess of the carbon-based material. The carbonaceous material is preferably carbon black, graphite particles, amorphous carbon, carbon nanotubes, carbon nanofibers, vapor grown carbon fibers, and the like.

In addition, when calcining hydrogen silsesquioxane in the production method, it is preferable to add 10 to 90% by weight of the total amount of the hydrogen silsesquioxane and carbon precursor mixture together with the hydrogen silsesquioxane. If the content is greater than 90, there is a problem of reducing energy density, and if it is less than 10, there is a problem that the amount of carbon remaining after the carbonization reaction is small, so that mixing with the carbon material becomes meaningless.

 The carbon precursor is preferably petroleum pitch, coal tar pitch, sucrose, sucrose, phenol resin, epoxy resin, furfuryl alcohol, polyvinyl chloride, polyvinyl alcohol, and the like. .

The present invention will be described in more detail with reference to the following examples and comparative examples. However, an Example is for illustrating this invention and does not limit the scope of the present invention only by these.

Preparation of Silicon Oxide

Example  One

1.5 g of triethoxysilane was added to 10 ml of ethanol and stirred for 30 minutes. 0.6 g of 0.5 M HCl solution was added thereto and stirred for 6 hours. After stirring was complete, the solution was allowed to gelate at room temperature for 2 days while preventing contact with outside air.

The gelled solution was then left in an 80 ° C. oven for 2 days to evaporate ethanol and water to obtain a white powder. The white powder was calcined for 1 hour in an argon atmosphere (flow rate = 100ml / min) at 900 ° C. to obtain silicon oxide (SiOx).

Example  2

1 g of silicon oxide powder obtained in Example 1 and 0.4 g of petroleum pitch (Mitsubishi chemical, softening point 250 ° C.) were added to 20 ml of THF (tetrahydrofuran), followed by stirring for 30 minutes. The solution was then stirred continuously to evaporate THF to obtain a powder. The powder was calcined for 1 hour in an argon atmosphere (flow rate = 100 ml / min) at 900 ° C. to obtain a silicon oxide coated with a carbonaceous material.

Example  3

1.5 g of tri (ethoxy) silane was added to 10 ml of ethanol, and then 0.6 g of graphite powder (Timcal, SFG-6) was added thereto, followed by stirring for 30 minutes. To obtain a composite of silicon oxide and graphite.

Comparative example  One

SiO manufactured by Japan High Purity Chemical Co., Ltd. was directly obtained and used.

Comparative example  2

Silicon oxide coated with a carbon-based material was prepared in the same manner as in Example 2, except that silicon oxide (SiO) of Comparative Example 1 was used instead of silicon oxide (SiOx) prepared in Example 1.

XRD (X- ray diffraction ) Measure

X-ray diffraction experiment of the silicon oxide prepared in Example 1 was performed. The experimental results are shown in FIG.

As shown in Figure 1 it can be seen that the silicon oxide prepared in Example 1 is an amorphous silicon oxide.

XPS (X- ray photoelectron spectrum ) Measure

X-ray photoelectric experiments were performed on the silicon oxides of Example 1 and Comparative Example 1, respectively. The instrument used was a PHI model Q2000. The experimental conditions were X-ray source, mono Al k 1486.6 eV, 100 m. The experimental results are shown in Table 1 and FIG. 2.

Table 1Sample Si2p (1)-99.2 eV Si2p (2) -100.8 eV Si2p (3)-103.0 eV Si2p (4) -105.4 eV Comparative Example 1 6.6% 2.12% 23.35% 2.1% Example 1 1.5% 1.08% 16.64% 10.8%

As shown in Table 1 and FIG. 2, atomic% (atomic%) calculated from the characteristic peak (peak (4)) of silicon appearing at 105.4 eV exceeded 10% for the silicon oxide of Example 1, but the comparative example Silicon oxide of 1 was less than 3%.

The high atomic% of silicon having such a high binding energy is believed to be due to the presence of a structure such as nanopore (nanopore) in the oxide in the silicon oxide of Example 1.

In FIG. 2, peak (1) is a peak corresponding to elemental silicon, peak (3) is a peak corresponding to SiO ₂ , and peak (2) is non-stoichiometirc silicon. It is the peak corresponding to oxide.

Cathode manufacturing

Example  4

Silicon oxide, carbon black (manufactured by Timcal, Inc.) and polyvinylidene fluoride (PVDF, polyvinylidene fluoride, 5 wt%) prepared in Example 1 were mixed at a weight ratio of 75:15:10 to N- Slurry was prepared in methylpyrrolidone (NMP, N-methyl pyrrolidone). After applying the slurry to a copper foil (Cu foil) to form a film thickness of 50㎛ using a doctor blade. Subsequently, the slurry coated with the copper foil was vacuum dried at 120 ° C. for 2 hours to prepare a negative electrode.

Example  5

A negative electrode was manufactured in the same manner as in Example 4, except that the silicon oxide prepared in Example 2 was used instead of the silicon oxide prepared in Example 1.

Example  6

A negative electrode was manufactured in the same manner as in Example 4, except that the silicon oxide prepared in Example 3 was used instead of the silicon oxide prepared in Example 1.

Comparative example  3

A negative electrode was manufactured in the same manner as in Example 4, except that the silicon oxide of Comparative Example 1 was used instead of the silicon oxide prepared in Example 1.

Comparative example  4

A negative electrode was manufactured in the same manner as in Example 4, except that the silicon oxide prepared in Comparative Example 2 was used instead of the silicon oxide prepared in Example 1.

Lithium battery manufacturers

Example  7

The negative electrode plate prepared in Example 4 was made of lithium metal as a counter electrode, and a polypropylene separator (Cellgard 3510) and 1.3 M LiPF ₆ were added to EC (ethylene carbonate) + DEC (diethyl carbonate) (3: 7 volume ratio). A coin cell of the CR2016 standard was prepared using the dissolved solution as an electrolyte.

Example  8 to 9 and Comparative example  5 to 6

Coin cells were manufactured in the same manner except for using the negative electrode plates prepared in Examples 5 to 6 and Comparative Examples 3 to 4 instead of the negative electrode plates prepared in Example 4.

Charging and discharging  Experiment

The coin cells prepared in Examples 7 to 9 and Comparative Examples 5 to 6 were respectively charged with a constant current until a current of 500 mA per 1 g of the active material reached 0.001 V with respect to the Li electrode, and then maintained at a voltage of 0.001 V. Constant voltage charging was performed until the current was lowered to 5 mA per gram of active material. After the charging was completed, the cell was subjected to a rest period of about 30 minutes, and then discharged by constant current discharge until the voltage reached 1.5 V at a current of 50 mA per 1 g of the active material. This was repeated 50 times. The discharge capacity was measured according to the number of cycles, respectively. Dose retention was calculated from this. The capacity retention rate is represented by the following equation.

<Equation 1>

Capacity retention rate (%) = discharge capacity in 30 ^th cycle / discharge capacity in 1 ^st cycle ㅧ 100

The charge and discharge test results for the coin cells of Examples 7 to 9 and Comparative Examples 5 to 6 are shown in Table 1 and FIGS. 3A and 3B, respectively.

TABLE 1

battery 1st cycle discharge capacity (mAh / g) 30th cycle discharge capacity (mAh / g) Capacity retention rate (%) Example 7 516 99 19.3 Example 8 905 546 60 Example 9 736 477 64.8 Comparative Example 5 393 35 9 Comparative Example 6 427 26 6.1

As shown in FIGS. 3A and 3B, the storage capacity of lithium was similar to that of the battery using the silicon oxide of Example 7 (FIG. 3A) compared to the battery using the silicon oxide of Comparative Example 1 (FIG. 3B). The release capacity of reversible lithium was significantly increased.

In addition, as shown in Table 1, the capacity retention rate of the 30 ^th cycle was also significantly increased in comparison with the comparative examples.

These results indicate the possibility that the life of the battery can be significantly improved. This difference indicates that the silicon oxides according to the embodiment of the present invention have a structure in which the atomic% of silicon having an abnormally high binding energy (105.4ev) is greater than 10% as shown in the XPS experiment results. It is judged to have excellent storage / release characteristics of lithium by such a structure.

In addition, the silicon oxide of the present invention can be easily produced by firing in a simple inert atmosphere, unlike a conventional silicon oxide manufacturing method that requires a high temperature firing or quenching process of 1200 ° C. or higher.

1 is a graph showing the results of X-ray diffraction experiment of the negative electrode active material of Example 1.

2 is a graph showing the results of the X-ray photoelectric experiment of the negative electrode active material of Example 1 and Comparative Example 2.

3A and 3B are graphs showing the potential-capacitance at the first charge / discharge of the lithium batteries of Example 7 and Comparative Example 5 employing the negative electrode active materials of Example 1 and Comparative Example 1, respectively.

Claims (7)

Hydrogen silsesquioxane (hydrogen silsesquioxane, HSQ) is prepared by firing in a temperature range of 900 to 1300 ℃ under an inert atmosphere, In the X-ray photoelectric spectrum, a silicon peak having a binding energy of 105 to 106 eV and a full width at half maximum (FWHM) of 1.6 to 2.4 eV, and the atomic% calculated from the area of the peak is 8 or more. A silicon oxide-based composite anode active material containing amorphous silicon oxide represented by general formula SiO _x (1 <x <1.7) having a value. The silicon oxide-based composite anode active material according to claim 1, wherein the atomic% calculated from the area of the peak has a value of 8 to 10.8. The silicon oxide-based composite anode active material according to claim 1, wherein the atomic% calculated from the area of the peak has a value of 10 to 10.8. The silicon oxide-based composite anode active material of claim 1, wherein the silicon oxide-based composite anode active material further includes carbon-based particles dispersed in the amorphous silicon oxide. The silicon oxide-based composite anode active material of claim 1, wherein the silicon oxide-based composite anode active material further includes a carbon-based coating layer formed on the amorphous silicon oxide. A negative electrode comprising the silicon oxide-based composite negative electrode active material according to any one of claims 1 to 5. A lithium battery comprising the negative electrode according to claim 6.

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