KR101859817B1 - Porous 1D nanotubes Metal-Metal oxide or Metal oxide-Metal oxide Hetero-composite coated by Metal Nanoparticles, High Capacity Lithium Anode Materials including the same, and Manufacturing Method thereof - Google Patents

Abstract

A one-dimensional porous nanotube composed of a metal-metal oxide or a metal oxide-metal oxide-coated heterogeneous complex coated with metal nanoparticles, a negative electrode active material for a high capacity secondary battery comprising the same, and a method of manufacturing the same. A metal-metal oxide or metal oxide-metal oxide having catalytic properties capable of decomposing Li ₂ O, which is composed of a heterogeneous complex, is a one-dimensional porous nanotube; The high-conductivity metal nanoparticles may be formed by coating a one-dimensional porous nanotube composed of a heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide.

Description

TECHNICAL FIELD [0001] The present invention relates to a one-dimensional porous nanotube composed of a metal-metal oxide or a metal oxide-metal oxide mixed with metal nanoparticles coated thereon, an anode active material for a high capacity secondary cell comprising the metal nanoparticle, Metal oxide Hetero-composite coated by Metal Nanoparticles, High Capacity Lithium Anode Materials including the same, and Manufacturing Method thereof}

The present invention relates to a method for manufacturing a one-dimensional porous nanotube coated with metal nanoparticles and an anode active material for a secondary battery using the same. More particularly, the present invention relates to a metal-metal oxide coated metal nanoparticle or a metal oxide- The present invention relates to a one-dimensional porous nanotube composed of a composite material, a negative electrode active material for a high capacity secondary battery comprising the same, and a method of manufacturing the same.

Since it is known that carbon dioxide is a major cause of the rapid global warming, countries are tightening their regulations on carbon dioxide emissions. As a result, research on electric vehicles that do not use fossil fuels is actively under way. Lithium secondary batteries are currently being used as power sources for electric vehicles due to advantages such as high operating voltage, high energy density, and low self-discharge rate without memory effect, which is a fatal problem of conventional nickel-cadmium batteries . However, graphite used as an anode active material of a conventional lithium secondary battery has a low theoretical capacity (372 mAh g < ^-1 >) and a low output characteristic, so that the lithium secondary battery for an electric vehicle requiring high capacity and high output characteristics This is a difficult situation. In 2000, P. Poizot et al. Reported that transition metal oxides such as CoO, NiO, and Co ₃ O ₄ have stable lifetime characteristics, high capacity, and high output characteristics as negative electrode active materials for lithium secondary batteries There is a growing interest in next-generation anode active materials to replace conventional graphite cathodes. These high-capacity transition metal oxides are classified into 1) reversible conversion reaction, 2) reversible conversion reaction, and 2) reversible conversion reaction.

The following is an example of reversible alloying reaction after irreversible conversion reaction.

M _x O _y + 2yLi ⁺ + 2ye ^- ? XM + yLi ₂ O (Equation 1)

M + zLi ⁺ + ze ^-? Li _z M (Equation 2)

Here, the metal oxide (M _x O _y ) made of the metal M reacts with the lithium ion (Li ⁺ ) first to convert it into the metal (M) and the lithium oxide (Li ₂ O) Then, the metal (M) reacts reversibly with lithium according to the formula (2), thereby realizing the capacity. At the time of discharging, the reverse reaction of (Equation 2) takes place and the lithium-metal alloy (Li _z M) is again converted into lithium ion and metal (M).

A reversible conversion reaction occurs in the following cases.

M _x O _y + 2yLi ⁺ + 2ye ^- ↔ xM + yLi ₂ O (Equation 3)

Here, a metal oxide (M _x O _y ) made of a metal M reacts with lithium ions (Li ⁺ ) to convert metal (M) and lithium oxide (Li ₂ O) Lithium oxide (Li ₂ O) reacts partially with metal (M) and converts to lithium ion and metal oxide (M _x O _y ) to realize capacity.

When the alloying reaction reversibly occurs after the irreversible conversion reaction, Li ₂ O, which is initially produced, exhibits a high irreversible capacity because it is no longer involved in the charge-discharge reaction. In addition, even when a reversible conversion reaction occurs, a considerable amount of lithium ions are converted to Li ₂ O and only a part of the lithium ions are decomposed again into lithium ions, so that the irreversible capacity also exhibits a high irreversible capacity.

Since only a limited amount of lithium ions is supplied from the positive electrode, a reversible reaction with the negative electrode active material is very important. In order to use a transition metal oxide having a high capacity and excellent output characteristics as a next-generation negative active material, Li ₂ O generated at the initial charge should be converted into lithium ions as much as possible during discharge to minimize irreversible capacity.

In addition, when the transition metal oxide is charged, the lifetime characteristics are deteriorated due to breakdown of the active material due to high volume expansion (~ 300%) and desorption from the current collector, and low electric conductivity (10 ^-3 to 10 ^-14 S cm ^-1 ) The use of a large amount of conductive material is also a problem to be solved for commercialization.

In order to alleviate the volume expansion of the transition metal oxide, bulk particles are crushed into nanoparticles to reduce the stress applied to the transition metal oxide particles upon volume expansion, or introduce a porous structure, This is not the case.

In order to improve the electrical conductivity of the transition metal oxide, a study was conducted mainly on the surface of the transition metal oxide coated with a conductive material. Research has been conducted on coatings of highly conductive carbon on the surface of transition metal oxides to obtain improved cycling and high rate charging and discharging results. In addition, metal, graphene, reduced graphene Oxide has been coated on the surface of the transition metal oxide to improve the electrical conductivity. This surface coating not only improves the electrical conductivity but also stabilizes the unstable transition metal oxide / electrolyte interface to improve the cycle characteristics, making it an indispensable requirement for using the transition metal oxide as a high capacity anode active material. However, the conventional methods have been limited to chemical vapor deposition (CVD), physical vapor deposition (CVD), and the like, which are explosive and harmful to the human body under high temperature or high pressure (CH ₄ , C ₂ H ₄ , C ₇ H ₈ , ), A carbon coating layer is introduced on the surface of the transition metal oxide. This method is not only dangerous but also requires expensive facilities and processes, and is particularly difficult to mass-produce. Also, the transition metal oxide may be reduced upon treatment in a high temperature and inert atmosphere, and the phase may change.

No studies have been conducted to improve the initial conversion efficiency of transition metal oxides. In some articles, it has been reported that when a specific transition metal such as Ni, Cu, Co is bound to a transition metal oxide in the form of nanoparticles, Li ₂ O is decomposed in the discharge process.

In order to use the transition metal oxide as a next-generation anode active material, a new process that can easily produce large quantities with ease is required, along with studies for improving initial conversion efficiency, relaxation of volume expansion, and improvement of low electric conductivity.

Embodiments of the present invention relate to one-dimensional porous nanotubes composed of heterogeneous complexes, which can be produced by simple and mass-producible processes such as metal-metal oxides coated with metal nanoparticles capable of improving conductivity and alleviating bulk expansion upon charging Or a mixed oxide of a metal oxide and a metal oxide, and a negative electrode active material for a high capacity secondary battery comprising the one-dimensional porous nanotube negative electrode active material and a method of manufacturing the same.

According to an aspect of the present invention, there is provided an anode active material for a high-capacity secondary battery, wherein a different type of nanoparticle or a different kind of nano-grain has a uniform composition distribution, A porous one-dimensional tube composed of a heterogeneous complex of a metal oxide or a metal oxide-metal oxide, and metal nanoparticles additionally bonded to the inner surface and the outer surface of the porous one-dimensional tube.

Wherein the relative weight ratios of the metal, the metal oxide, and the metal nanoparticles in the metal-metal oxide composite are 10 to 89.9 wt%, 10 to 89.9 wt%, and 10 wt% to 10 wt%, respectively, in the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or metal oxide- To 89.9 wt% and 0.1 to 5 wt%, and the sum of the relative weight ratios may be 100 wt%. In the metal oxide-metal oxide composite, the first metal oxide has a relative weight ratio of 10 to 89.9 wt% to the second different metal oxide, the relative weight ratio of the metal nanoparticles is 0.1 to 5 wt% May be 100 wt%.

A metal oxide forming the porous one-dimensional _{tube, ZnO, SnO 2, WO 3} , Fe 2 O 3, Fe 3 O 4, NiO, CuO, Cu 2 O, Zn 2 SnO 4, CoO, Co 3 O 4, V 2 O ₅ , MnO ₂ , Mn ₂ O ₃ Mn ₃ O ₄ , Ta ₂ O _5, or a complex thereof. The metal may be at least one selected from the group consisting of Fe, Ni, Cr, Mn, Co, Cu, V, Zn, W and alloys thereof. At this time, when the metal oxide nanoparticles or the metal oxide-metal nanoparticles are bound to each other in the form of heterogeneous metal oxide-metal nanoparticles, they exhibit catalytic properties and can act to decompose Li ₂ O generated during the charging process and increase the conversion efficiency.

The length of the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide may have a range of 1 탆 to 1000 탆. And more preferably in the range of 1 占 퐉 to 10 占 퐉. When the length of the porous one-dimensional tube composed of a heterogeneous complex is smaller than 1 탆, the density of the electrode is lowered at the time of forming the negative electrode. When the thickness is more than 10 탆, the effect of buffering the stress against the volume expansion Can fall.

The ratio (length of the tube) / (outer diameter of the tube) (ratio of the tube length to the outer diameter of the tube) of the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or metal oxide- Lt; / RTI > More preferably, the ratio of (length of tube) / (outer diameter of tube) may be selected in the range of 10 to 500. If it is less than 10, there is a high possibility that the structure of the tube is collapsed. If it is more than 500, penetration of the electrolyte into the tube is difficult and the rate characteristic may be deteriorated.

The heterogeneous nanoparticles or the nano-grains constituting the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide have a size range of 0.1 to 200 nm . And more preferably in the range of 0.5 to 50 nm. If naejineun nanoparticles heterologous (nanoparticle) than 0.5 nm smaller the nano-grains (nano-grain) of heterogeneous and can lead to changes in the charge-discharge procedure, is greater than 50 nm is a catalyst deteriorate discharge when Li ₂ O decomposition Can be difficult.

The metal nanoparticles additionally bonded to the inner and outer surfaces of the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide are Ir, Os, Po, Rh, Ru, Pt, Pd, And any metal or alloy that can increase the electrical conductivity of the tube. The metal nanoparticles may have a size range of 0.1 to 20 nm, more preferably 0.5 to 10 nm. If the size of the metal nanoparticles is less than 0.5 nm, the electrical conductivity of the porous one-dimensional tube made of a heterogeneous complex can not be sufficiently improved. If the size of the metal nanoparticles is larger than 10 nm, the reaction between the porous one- Can be degraded.

The porous one-dimensional tube composed of a heterogeneous complex of metal-metal oxide or metal oxide-metal oxide coated with the metal nanoparticles may include micropores having an average diameter of 0.1 to 10 nm, more preferably 0.5 to 5 lt; RTI ID = 0.0 > nm. < / RTI > If the diameter of the micropores is less than 0.5 nm, penetration of the electrolyte into the tube may be difficult. If the diameter of the micropores is 5 nm or more, the structure of the tube may collapse upon charging and discharging.

The negative electrode for a secondary battery according to another aspect of the present invention may further comprise a binder and a conductive material. Here, the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide may be mixed with the binder and the conductive material and formed by slurry casting on the current collector.

According to another aspect of the present invention, there is provided a method for preparing a negative electrode active material for a secondary battery, comprising: mixing a metal precursor and a metal oxide precursor together with a polymer in two or more solvents having solubilities in both metal and metal oxide precursors and polymers, Polymer precursor / polymer composite fiber in which a metal oxide precursor and a polymer are mixed, or a metal oxide precursor / polymer composite fiber in which a metal oxide precursor and a polymer are mixed; The metal precursor / metal oxide precursor / polymer composite fiber is subjected to a rapid thermal treatment to evaporate the solvent having a low boiling point in the composite fiber. The precursor is moved to the outside of the composite fiber to be reduced or oxidized to form nanoparticles or nano- Forming a porous one-dimensional tube composed of a heterogeneous complex of a metal-metal oxide or a metal oxide-metal oxide; Uniformly coating metal nanoparticles capable of imparting high electrical conductivity to a porous one-dimensional tube-shaped surface and an inner surface composed of a heterogeneous complex of the metal-metal oxide or metal oxide-metal oxide through a metal-mirror reaction; And a porous one-dimensional tube composed of a metal-metal oxide or a metal oxide-metal oxide coated with the metal nanoparticles is mixed with a binder and a conductive material, and slurry casting is performed on the current collector to form a negative electrode for a secondary battery And the like. Further, a step of mixing a porous one-dimensional tube composed of a heterogeneous complex of the metal-metal oxide or metal oxide-metal oxide with a binder and a conductive material, and slurry casting the mixture on the current collector to manufacture a cathode for a secondary battery . The ratio of the porous one-dimensional tube, the conductive material and the binder composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide used in the cathode production is 60 to 80 wt%, 5 to 15 wt%, 5 to 20 wt% And the sum of the respective relative weight ratios is 100 wt%.

According to the embodiment of the present invention, the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide has the following characteristics: 1) it has high electrical conductivity and excellent output characteristics; 2) 3) Li ₂ O is converted into lithium ion as much as possible in the discharge process and its irreversible capacity is remarkably low. Therefore, a next generation negative electrode active material and a secondary battery negative electrode using the same can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic representation of a porous one-dimensional tube composed of a heterogeneous complex of a metal-metal oxide or metal oxide-metal oxide, according to one embodiment of the present invention.
2 is a flow chart illustrating a method of fabricating a porous one-dimensional tube anode active material comprised of a heterogeneous complex of metal-metal oxide or metal oxide-metal oxide in an embodiment of the present invention.
FIG. 3 is a cross-sectional view of a metal precursor / metal oxide precursor / polymer composite fiber in which a precursor and a polymer are mixed in a comparative example of the present invention, and (b) a metal-metal oxide or a metal oxide- (SEM) photograph of a porous one-dimensional tube composed of a composite material.
FIG. 4 is a view showing an X-ray diffraction pattern of a porous one-dimensional tube composed of a heterogeneous complex of a metal-metal oxide or a metal oxide-metal oxide according to an embodiment of the present invention.
FIG. 5 illustrates a porous one-dimensional tube composed of a heterogeneous complex of a metal-metal oxide or a metal oxide-metal oxide coated with metal nanoparticles according to an embodiment of the present invention (a) and (b) a transmission electron microscope Electron Microscope, TEM).
FIG. 6 is a transmission electron microscope dark field image of a porous one-dimensional tube composed of a metal-metal oxide or a metal oxide-metal oxide heterogeneous complex coated with metal nanoparticles according to one embodiment of the present invention (a) And (b) the Ag nanoparticles are uniformly coated on the surface by energy spectral analysis thereof.
7 is a graph showing a cyclic voltammogram of a porous one-dimensional tube composed of a metal-metal oxide or a metal oxide-metal oxide heterogeneous composite coated with metal nanoparticles according to an embodiment of the present invention.
FIG. 8 is a graph showing initial cycle characteristics and rate characteristics of a secondary battery manufactured according to one embodiment and a comparative example of the present invention. FIG.
9 is a graph showing life characteristics obtained up to 500 cycles of a secondary battery manufactured according to an embodiment of the present invention and a comparative example.

Hereinafter, with reference to the accompanying drawings, reference will be made to the accompanying drawings, in which metal nanoparticles are coated to exhibit excellent conductivity characteristics, excellent in high-rate characteristics, and composed of a heterogeneous complex of metal-metal oxide or metal oxide- A method for manufacturing a one-dimensional porous nanotube negative electrode active material for a battery will be described in detail.

In the present invention, the metal oxide constituting the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide may be ZnO, SnO ₂ , WO ₃ , Fe ₂ O ₃ , Fe ₃ O ₄ , NiO, CuO , Cu ₂ O, Zn ₂ SnO ₄ , CoO, Co ₃ O ₄ , V ₂ O ₅ , MnO ₂ , Mn ₂ O ₃ Mn ₃ O ₄ , Ta ₂ O _5, or a complex thereof. Also, the metal should be understood as at least one selected from the group consisting of Fe, Ni, Cr, Mn, Co, Cu, V, Zn, W or their alloys. However, when the metal oxide nanoparticles or the metal oxide-metal nanoparticles are bonded to each other in the form of a metal oxide or metal nano-particle, the metal oxide or metal nanoparticle may exhibit catalytic properties to decompose Li ₂ O generated during the charging process, There is no restriction on metal elements.

In the present invention, it is to be understood that the length of the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or metal oxide-metal oxide is in the range of 1 탆 to 1000 탆. And more preferably in the range of 1 占 퐉 to 10 占 퐉. When the length of the porous one-dimensional tube composed of a heterogeneous complex is smaller than 1 탆, the density of the electrode is lowered at the time of forming the negative electrode. When the thickness is more than 10 탆, the effect of buffering the stress against the volume expansion Can fall.

In the present invention, it is to be understood that the ratio (tube length) / (tube diameter) of the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or metal oxide-metal oxide is in the range of 5 to 5000. More preferably, the ratio of (length of tube) / (outer diameter of tube) may be selected in the range of 10 to 500. If it is less than 10, there is a high possibility that the structure of the tube is collapsed. If it is more than 500, penetration of the electrolyte into the tube is difficult and the rate characteristic may be deteriorated.

In the present invention, the heterogeneous nanoparticles or the nano-grains constituting the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide may have a size of 0.1 to 200 nm Range. ≪ / RTI > And more preferably in the range of 0.5 nm to 50 nm. If naejineun nanoparticles heterologous (nanoparticle) than 0.5 nm smaller the nano-grains (nano-grain) of heterogeneous and can lead to changes in the charge-discharge procedure, is greater than 50 nm is a catalyst deteriorate discharge when Li ₂ O decomposition Can be difficult.

In the present invention, the metal nanoparticles additionally bonded to the inner surface and the outer surface of the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide may be Ir, Os, Po, Rh, Ru, Pt, Pd, Au , And Ag, or alloys thereof, and does not impose any restrictions on metals and alloys that can increase the electrical conductivity of the tube. The metal nanoparticles may have a size range of 0.1 to 20 nm, more preferably 0.5 to 10 nm. If the size of the metal nanoparticles is less than 0.5 nm, the electrical conductivity of the porous one-dimensional tube made of a heterogeneous complex can not be sufficiently improved. If the size of the metal nanoparticles is larger than 10 nm, the reaction between the porous one- Can be degraded.

In the present invention, the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or metal oxide-metal oxide coated with the metal nanoparticles may include micropores having an average diameter of 0.1 to 10 nm, Micropores having an average diameter of 0.5 to 5 nm. If the diameter of the micropores is less than 0.5 nm, penetration of the electrolyte into the tube may be difficult. If the diameter of the micropores is 5 nm or more, the structure of the tube may collapse upon charging and discharging.

The embodiments of the present invention are characterized in that the low conversion efficiency, which is a problem of the conventional metal oxide anode active material described above, is bonded in a heterogeneous form and exhibits a catalyst characteristic of decomposing Li ₂ O, To provide a negative electrode active material for a secondary battery having remarkably improved conversion efficiency and a method of manufacturing the same. In addition, through the solution process proceeding at a low temperature (50 ° C) in a porous one-dimensional tube shape capable of alleviating the volume expansion, the metal nanoparticles having significantly improved binding characteristics, lifetime characteristics and rate- Dimensional porous nanotube composed of a heterogeneous complex of a metal-metal oxide or a metal oxide-metal oxide, a negative electrode active material for a high-capacity secondary battery comprising the same, and a method of manufacturing the same.

For this purpose, a one-dimensional structure is fabricated using an electrospinning method that is easy to mass-produce, a simple calcination process is performed in the air, and then a highly conductive metal nanoparticle is introduced through a simple solution process at room temperature, And a metal oxide anode active material for a secondary battery having both a high rate and a long life.

Specifically, the first object of the present invention is to provide a next generation anode active material which is composed of a heterogeneous complex of a metal-metal oxide or a metal oxide-metal oxide and has a catalytic effect of decomposing Li ₂ O upon discharge, will be.

Second, the present invention provides a next-generation anode active material having a porous one-dimensional tube structure, which can effectively alleviate volumetric expansion during charging and thus has a long life.

Third, it is intended to provide a next generation anode active material having a very high rate-determining characteristic by coating a highly conductive metal nanoparticle on the surface of a porous one-dimensional tube by a simple solution process at room temperature.

The porous one-dimensional tube 300 composed of the metal nanoparticles-coated metal-metal oxide or the metal oxide-metal oxide composite obtained in the present invention has a remarkably high electrical conductivity. Due to the porous one-dimensional tube structure, There is a feature that can effectively alleviate.

The metal oxide of the porous one-dimensional tube 200 composed of the heterogeneous metal-metal oxide or metal oxide-metal oxide composite obtained in the present invention may be ZnO, SnO ₂ , WO ₃ , Fe ₂ O ₃ , Fe ₃ O ₄ , NiO, CuO , Cu ₂ O, Zn ₂ SnO ₄ , CoO, Co ₃ O ₄ , V ₂ O ₅ , MnO ₂ , Mn ₂ O ₃ Mn ₃ O ₄ , Ta ₂ O ₅ or a composite thereof, and the metal may be at least one selected from the group consisting of Fe, Ni, Cr, Mn, Co, Cu, V, Zn, W, If one or more of the metals is selected as a nanoparticle bound to a different kind of metal oxide, it exhibits catalytic properties and decomposes Li ₂ O generated during the charging process, thereby enhancing the conversion efficiency. I do not.

It is to be understood that the length of the porous one-dimensional tube 200 composed of the heterogeneous complex of metal-metal oxide or metal oxide-metal oxide obtained in the present invention has a range of 1 탆 to 1000 탆. And more preferably in the range of 1 占 퐉 to 10 占 퐉. When the length of the porous one-dimensional tube 200 made of a heterogeneous complex is less than 1 탆, the density of the electrode is lowered at the time of forming the negative electrode. When the thickness is more than 10 탆, The buffering effect can be reduced.

The ratio (tube length) / (tube diameter) of the porous one-dimensional tube 200 composed of the heterogeneous complex of the metal-metal oxide or metal oxide-metal oxide obtained in the present invention should be understood to have a range of 5 to 5000 do. More preferably, the ratio of (length of tube) / (outer diameter of tube) may be selected in the range of 10 to 500. If it is less than 10, there is a high possibility that the structure of the tube is collapsed. If it is more than 500, penetration of the electrolyte into the tube is difficult and the rate characteristic may be deteriorated.

The heterogeneous nanoparticles or the nano-grains constituting the porous one-dimensional tube 200 made of the heterogeneous composite of the metal oxide-metal oxide obtained according to the present invention have a size range of 0.1 to 200 nm . And more preferably in the range of 0.5 nm to 50 nm. If naejineun nanoparticles heterologous (nanoparticle) than 0.5 nm smaller the nano-grains (nano-grain) of heterogeneous and can lead to changes in the charge-discharge procedure, is greater than 50 nm is a catalyst deteriorate discharge when Li ₂ O decomposition Can be difficult.

The porous one-dimensional tube 200 composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide obtained in the present invention may include micropores having an average diameter of 0.1 to 10 nm, Micropores having an average diameter of 5 nm. If the diameter of the micropores is less than 0.5 nm, penetration of the electrolyte into the tube may be difficult. If the diameter of the micropores is 5 nm or more, the structure of the tube may collapse upon charging and discharging.

The metal nanoparticles 310 may be coated on the surface of a porous one-dimensional tube 200 composed of a heterogeneous complex of a metal-metal oxide or a metal oxide-metal oxide.

The metal nanoparticles 310 may be a metal selected from the group consisting of Ir, Os, Po, Rh, Ru, Pt, Pd, Au and Ag or alloys thereof. There is no restriction.

Here, the metal nanoparticles 310 may have a size range of 0.1 to 20 nm, and more preferably 0.5 to 10 nm. If the size of the metal nanoparticles is less than 0.5 nm, the electrical conductivity of the porous one-dimensional tube made of a heterogeneous complex can not be sufficiently improved. If the size of the metal nanoparticles is larger than 10 nm, the reaction between the porous one- Can be degraded.

The porous one-dimensional tube composed of the metal-metal oxide or the metal oxide-metal oxide coated complex obtained by the present invention coated with the metal nanoparticles may include micropores having an average diameter of 0.1 to 10 nm, May include micropores having an average diameter of 0.5 to 5 nm. If the diameter of the micropores is less than 0.5 nm, penetration of the electrolyte into the tube may be difficult. If the diameter of the micropores is 5 nm or more, the structure of the tube may collapse upon charging and discharging.

The porous one-dimensional tube 300 composed of the metal nanoparticle-coated metal-metal oxide or metal oxide-metal oxide composite obtained in the present invention is mixed with a binder and a conductive material, and slurry casting ) To produce a negative electrode for a secondary battery. The ratio of the porous one-dimensional tube (300), the conductive material and the binder composed of the metal-metal oxide coated with the metal nano-particles or the heterogeneous complex of the metal oxide-metal oxide used in the cathode production is 60 to 80 wt% To 15 wt%, and 5 to 15 wt%, respectively, and the sum of the relative weight ratios is 100 wt%.

FIG. 2 is a flowchart showing a method for manufacturing a porous one-dimensional tube anode active material composed of a metal-metal oxide coated with metal nanoparticles or a heterogeneous complex of metal oxide-metal oxide according to an embodiment of the present invention.

Referring to FIG. 2, a method of manufacturing a porous one-dimensional tube anode active material composed of a metal-metal oxide coated with metal nanoparticles or a heterogeneous complex of a metal oxide-metal oxide as shown in FIG. 1 can be specifically shown .

The method for manufacturing an anode active material for a secondary battery according to the present invention comprises the steps of: (a) mixing a metal precursor or a metal oxide precursor with a polymer in a solvent having a solubility in both metal and metal oxide precursors and a polymer and mixing two or more solvents having different boiling points (S10) of obtaining a metal precursor / polymer composite fiber or a metal oxide precursor / polymer composite fiber in which the metal oxide precursor and the polymer are mixed; (b) Rapid heat treatment of the metal precursor / polymer composite fiber or metal oxide precursor / polymer composite fiber causes the solvent having a low boiling point in the composite fiber to evaporate first, and the precursor is moved to the outside of the composite fiber to reduce or oxidize the nanoparticle or (S20) forming a porous one-dimensional tube composed of a heterogeneous complex of a metal-metal oxide or a metal oxide-metal oxide while forming a nanogram and removing the polymer at the same time; (c) uniformly coating metal nanoparticles capable of imparting high electrical conductivity on the inner and outer surfaces of a porous one-dimensional tube formed of a heterogeneous complex of the metal-metal oxide or metal oxide-metal oxide through a metal-mirror reaction (S30); And (d) mixing a porous one-dimensional tube composed of a metal-metal oxide coated with metal nanoparticles or a heterogeneous complex of a metal oxide-metal oxide with a binder and a conductive material, slurry casting the current collector, And a step (S40) of manufacturing a negative electrode for a secondary battery.

The ratio of the porous one-dimensional tube, the conductive material and the binder composed of the metal-metal oxide or the heterogeneous complex of the metal oxide-metal oxide coated with the metal nano-particles used in the cathode production is 60 to 80 wt%, 5 to 15 wt % And 5 to 20 wt%, respectively, and the sum of the relative weight ratios is 100 wt%.

According to the embodiment of the present invention as described above, it is possible to provide a lithium _secondary battery which exhibits: 1) high electric conductivity, excellent output characteristics, 2) excellent lifetime characteristics due to relaxation of volume expansion of transition metal oxide upon charging, and 3) The present invention can provide a next-generation metal-metal-oxide-based negative electrode active material and a secondary battery negative electrode using the metal-oxide-negative-electrode active material, wherein the irreversible capacity is drastically reduced.

Each process according to an embodiment of the present invention will be described in more detail below.

First, in step (a), a metal precursor / metal oxide precursor / polymer composite fiber in which a metal precursor and a polymer are mixed may be prepared.

The polymer may be selected from the group consisting of styrene acrylonitrile (SAN), polyacrylonitrile (PAN), polyvinyl acetate (PVAc), polyvinylpyrrolidone (PVP) ), Polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyacrylic acid (PAA), hydroxypropyl cellulose (HPC), polymethyl methacrylate PMMA, polymethylmethacrylate), or a mixture of at least one polymer.

Here, the solvent is selected from the group consisting of water, N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), ethanol (CH ₃ CH ₂ OH) CH ₃ OH), propanol (C ₃ H ₇ OH), tetrahydrofuran (THF), chloroform (CHCl ₃₎ and acetone (CH ₃ COCH ₃₎ a solvent having a different boiling points of two or more selected may be mixed in and It can be chosen to melt the above polymer.

The metal precursor may include a metal selected from the group consisting of Fe, Ni, Cr, Mn, Co, Cu, V, Zn and W and may be melted in at least one of the solvents selected in step (S10).

The metal oxide precursor (a) soluble in any one solvent or more of the selected solvent at the step (S10) when heat treated oxide _{ZnO, SnO 2, WO 3,} Fe 2 O 3, Fe 3 O 4, NiO, CuO, Cu 2 _{O, Zn 2 SnO 4, CoO} , Co 3 O 4, V 2 O 5, MnO 2, Mn 2 O 3 Mn ₃ O ₄ , and Ta ₂ O ₅ can be used.

Here, the polymer may be added in a mixed solvent such that the polymer has 5 to 15% by weight based on the solvent in which the two or more solvents having different boiling points are mixed, and the metal precursor or metal oxide precursor is 5 to 15% by weight based on the mixed solvent.

Here, a solution prepared by mixing a polymer, a metal precursor or a metal oxide precursor and two or more solvents having different boiling points is electrospun through a device composed of a spray nozzle connected to a metering pump, a high voltage generator, and a conductive current collector to form a metal oxide precursor and a polymer / Metal composite precursor / polymer composite fiber can be obtained.

Here, the current collector is placed on a grounded conductive substrate, and then a grounded conductive substrate is used as a cathode, and a spinning nozzle having a pump for controlling the discharge amount per hour is used as an anode. The metal precursor / polymer composite fiber or the metal oxide precursor / polymer composite fiber can be prepared by applying a voltage of 8 to 30 kV and a solution discharge rate of 5 to 200 μl / min.

Here, the electrospinning apparatus can be realized by a multi-nozzle system composed of more than 10,000 needles, and mass production using a cylinder type drum is also possible.

(b) In step (S20), the metal precursor / polymer composite fiber or the metal oxide precursor / polymer composite fiber is subjected to a rapid thermal treatment to evaporate the solvent having a low boiling point in the composite fiber, and the precursor is moved to the outside of the composite fiber, Thereby forming nanoparticles or nano-grains while simultaneously removing the polymer to form a porous one-dimensional tube composed of a heterogeneous complex of metal-metal oxide or metal oxide-metal oxide.

Here, the rapid thermal annealing may be performed at a temperature of 400 to 1000 ° C. for 30 minutes to 2 hours after a rapid heating step of 10 to 100 ° C. per minute. More preferably, the temperature rise can be performed at 10 to 30 占 폚. When the temperature raising rate is lower than 10 ° C, the rate at which the metal or metal oxide precursor moves to the outside of the conjugated fiber is too slow compared to the time at which the polymer is removed, so that the tube structure may not be formed. Or the rate at which the metal oxide precursor moves out of the conjugated fiber is too fast to form a continuous continuous tube structure. The heat treatment temperature is more preferably 500 to 800 占 폚. If the heat treatment temperature is lower than 500 ° C, the metal or metal oxide precursor and the polymer may not be completely decomposed, and if the heat treatment temperature is 800 Lt; 0 > C, it may be difficult to form a continuous tube structure.

It is to be understood that the length of the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or metal oxide-metal oxide is in the range of 1 탆 to 1000 탆. And more preferably in the range of 1 占 퐉 to 10 占 퐉. When the length of the porous one-dimensional tube composed of a heterogeneous complex is smaller than 1 탆, the density of the electrode is lowered at the time of forming the negative electrode. When the thickness is more than 10 탆, the effect of buffering the stress against the volume expansion Can fall.

Here, it is to be understood that the ratio (tube length) / (tube diameter) of the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or metal oxide-metal oxide is in the range of 5 to 5000. More preferably, the ratio of (length of tube) / (outer diameter of tube) may be selected in the range of 10 to 500. If it is less than 10, there is a high possibility that the structure of the tube is collapsed. If it is more than 500, penetration of the electrolyte into the tube is difficult and the rate characteristic may be deteriorated.

The different kind of nanoparticles or nano-grains constituting the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide may have a size range of 0.1 to 200 nm Should be understood as having. And more preferably in the range of 0.5 nm to 50 nm. If naejineun nanoparticles heterologous (nanoparticle) than 0.5 nm smaller the nano-grains (nano-grain) of heterogeneous and can lead to changes in the charge-discharge procedure, is greater than 50 nm is a catalyst deteriorate discharge when Li ₂ O decomposition Can be difficult.

(c) In step (S30), metal nanoparticles capable of imparting high electrical conductivity are uniformly coated on the inner and outer surfaces of the porous one-dimensional tube formed of the heterogeneous metal-metal oxide or metal oxide-metal oxide composite .

Here, the metal coated on the inner surface and the outer surface of the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide may be formed through a metal-mirror reaction.

The metal nanoparticles additionally bonded to the inner and outer surfaces of the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide may be Ir, Os, Po, Rh, Ru, Pt, Pd, Ag, or an alloy thereof, and does not limit the metal or the alloy which can increase the electrical conductivity of the tube. The metal nanoparticles may have a size range of 0.1 to 20 nm, more preferably 0.5 to 10 nm. If the size of the metal nanoparticles is less than 0.5 nm, the electrical conductivity of the porous one-dimensional tube made of a heterogeneous complex can not be sufficiently improved. If the size of the metal nanoparticles is larger than 10 nm, the reaction between the porous one- Can be degraded.

Here, the metal nanoparticles additionally bonded to the inner and outer surfaces of the porous one-dimensional tube composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide may be coated through a metal-mirror reaction. Wherein the metal-mirror reaction comprises the steps of (1) to (6): (1) dispersing the prepared porous tubular nanofibers in ethanol; (2) dispersing a metal precursor containing one metal ion selected from Ir, Os, Po, Rh, Ru, Pt, Pd, Au, and Ag into the prepared solution; (3) heating the solution to about 50 캜; (4) mixing the heated solution with an amine-based reducing agent; (5) stirring the mixed solution while heating to 50 DEG C for 10 minutes; And (6) filtering the solution.

Examples of the amine-based reducing agent used in the metal-mirror reaction include methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, t-butylamine, n-pentylamine, cyclopentyl Amines, isopentylamines, n-hexylamines, cyclohexylamines, n-octylamines, n-decylamines, 1-phenylethylamines, 2-phenylethylamines, allylamines, 2- Ethoxyethylamine and an amine-based reducing agent capable of binding metal nanoparticles to the inner and outer surfaces of a porous one-dimensional tube composed of a heterogeneous complex of the metal-metal oxide or metal oxide-metal oxide by reducing metal ions There is no restriction on the kind.

Here, the porous one-dimensional tube composed of the heterogeneous complex of metal-metal oxide or metal oxide-metal oxide coated with the metal nanoparticles may include micropores having an average diameter of 0.1 to 10 nm, Micropores having an average diameter of 5 nm. If the diameter of the micropores is less than 0.5 nm, penetration of the electrolyte into the tube may be difficult. If the diameter of the micropores is 5 nm or more, the structure of the tube may collapse upon charging and discharging.

Here, in a porous one-dimensional tube composed of a metal-metal oxide coated with metal nanoparticles or a heterogeneous complex of a metal oxide-metal oxide, the relative weight ratio of the metal to the metal-metal oxide composite is 10 to 89.9 wt% The content of the oxide may be 10 to 89.9 wt%, the content of the metal nanoparticles may be 0.1 to 5 wt%, and the sum of the relative weight ratios may be 100 wt%. In addition, in the metal oxide-metal oxide composite, the metal oxide has a relative weight ratio of 10 to 89.9 wt% to the other different metal oxides, the metal nano-particle content is 0.1 to 5 wt%, and the sum of the relative weight ratios is 100 wt %to be.

(d) In step S40, a porous one-dimensional tube composed of a metal-metal oxide or metal oxide-metal oxide composite coated with the metal nanoparticles is mixed with a binder and a conductive material, and slurry casting Slurry Casting) to produce a negative electrode for a secondary battery. The ratio of the porous one-dimensional tube, the conductive material and the binder composed of the heterogeneous complex of the metal-metal oxide or the metal oxide-metal oxide coated with the metal nano-particles used in manufacturing the anode is 60 to 80 wt%, 5 to 15 wt% 5 to 20 wt%, and the sum of the relative weight ratios is 100 wt%.

In addition, it is possible to provide a negative electrode manufacturing method for a secondary battery using the method for manufacturing a negative electrode active material for a secondary battery.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. The examples and comparative examples are merely intended to illustrate the present invention, and the present invention is not limited thereto.

Example 1: Secondary battery anode active material comprising a porous one-dimensional tube composed of a heterogeneous complex of a metal oxide (SnO ₂ ) -metal oxide (NiO) coated with 3 wt% of metal (Ag) nanoparticles

Hereinafter, a method for manufacturing a secondary battery anode active material including a porous one-dimensional tube composed of a heterogeneous complex of metal oxide (SnO ₂ ) -metal oxide (NiO) coated with metal nanoparticles (Ag) according to the present invention will be described in detail.

- Dissolve metal oxide precursors (SnCl ₂ , NiCl ₂ ) and polymers (Polyvinylpyrrolidone, PVP) in a solvent mixed with two solvents with different boiling points (Dimethylformamide, DMF and ethanol) with solubility in both precursor and polymer , electrospinning and a metal oxide precursor (SnCl _2, NiCl ₂₎ and the polymer (PVP) is a mixed metal oxide precursor (SnCl _2, NiCl ₂₎ / polymer (PVP) to obtain a composite fiber

First, 0.15 g of SnCl ₂ and 0.15 g of NiCl ₂ were added to 2 g of ethanol and stirred for 2 hours. Then, 0.7 g of PVP was added to 2 g of DMF and stirred for 2 hours. Then, the two solutions were mixed and further stirred for 6 hours to obtain a solution containing a metal oxide precursor (SnCl ₂ , NiCl ₂ ) / polymer (PVP). Electrospinning was carried out using the obtained solution to obtain a metal oxide precursor (SnCl ₂ , NiCl ₂ ) / polymer (PVP) composite fiber. The electrospinning was carried out by applying a voltage of 15 kV and a nozzle size of 21 GA was used. The gap between the current collector and the nozzle was 13 cm and electrospinning was performed at a discharge rate of 20 분 per minute. A stainless steel substrate was used as the collector substrate.

- Rapid heat treatment of metal oxide precursors (SnCl ₂ , NiCl ₂ ) and polymers (polyvinylpyrrolidone, PVP) leads to evaporation of the solvent with low boiling point in the composite fiber. The precursor is moved to the outside of the composite fiber, Forming nanocrystals and simultaneously removing the polymer to form a porous one-dimensional tube composed of a heterogeneous complex of metal oxide (SnO ₂ ) - metal oxide (NiO)

The resulting metal oxide precursor (SnCl ₂ , NiCl ₂ ) / polymer (PVP) composite fiber was heat-treated at a temperature of 700 ° C. for 2 hours through a rapid heating step of 10 ° C. per minute.

A porous one-dimensional tube-shaped outer surface composed of a heterogeneous complex of the metal oxide (SnO ₂ ) -metal oxide (NiO) obtained through a metal-mirror reaction with metal (Ag) nanoparticles capable of imparting high electrical conductivity, Lt; RTI ID = 0.0 >

A porous one-dimensional tube composed of the heterogeneous complex of the metal oxide (SnO ₂ ) -metal oxide (NiO) obtained was coated with Ag nanoparticles through a metal-mirror reaction. In the metal-mirror reaction, 0.2 g of the porous tubular nanofiber prepared above was dispersed in 24 ml of ethanol, and then 0.01 g of AgCl was added. After heating to 50 캜, 0.01 g of n-butylamine was added Followed by further stirring for 10 minutes. The solution was filtered and dried to finally obtain a porous one-dimensional tube composed of a heterogeneous complex of a metal oxide (SnO ₂ ) -metal oxide (NiO) coated with metal (Ag) nanoparticles.

A porous one-dimensional tube composed of a heterogeneous complex of a metal oxide (SnO ₂ ) -metal oxide (NiO) coated with metal (Ag) nanoparticles is mixed with a binder and a conductive material and slurry casting is performed on the current collector Step of producing negative electrode for secondary battery

In the present invention, 10 wt% of a negative electrode active material, 80 wt% of poly (acrylic acid), and 50 wt% of sodium carboxymethylcellulose (50/50 w / w) %, And Super-p carbon particles of 10 wt% were mixed, slurry-coated on a Cu current collector substrate, dried and rolled, and then punched to a predetermined size to prepare a negative electrode.

Comparative Example 1: Secondary battery anode active material comprising porous one-dimensional tube composed of heterogeneous complex of metal oxide (SnO ₂ ) -metal oxide (NiO)

Hereinafter, a method for manufacturing a secondary battery anode active material including a porous one-dimensional tube composed of a heterogeneous complex of a metal oxide (SnO ₂ ) -metal oxide (NiO) according to the present invention will be described in detail.

- Dissolve metal oxide precursors (SnCl ₂ , NiCl ₂ ) and polymers (Polyvinylpyrrolidone, PVP) in a solvent mixed with two solvents with different boiling points (Dimethylformamide, DMF and ethanol) with solubility in both precursor and polymer , electrospinning and a metal oxide precursor (SnCl _2, NiCl ₂₎ and the polymer (PVP) is a mixed metal oxide precursor (SnCl _2, NiCl ₂₎ / polymer (PVP) to obtain a composite fiber

First, 0.15 g of SnCl ₂ and 0.15 g of NiCl ₂ were added to 2 g of ethanol and stirred for 2 hours. Then, 0.7 g of PVP was added to 2 g of DMF and stirred for 2 hours. Then, the two solutions were mixed and further stirred for 6 hours to obtain a solution containing a metal oxide precursor (SnCl ₂ , NiCl ₂ ) / polymer (PVP). Electrospinning was carried out using the obtained solution to obtain a metal oxide precursor (SnCl ₂ , NiCl ₂ ) / polymer (PVP) composite fiber. The electrospinning was carried out by applying a voltage of 15 kV and a nozzle size of 21 GA was used. The gap between the current collector and the nozzle was 13 cm and electrospinning was performed at a discharge rate of 20 분 per minute. A stainless steel substrate was used as the collector substrate.

- Rapid heat treatment of metal oxide precursors (SnCl ₂ , NiCl ₂ ) and polymers (polyvinylpyrrolidone, PVP) leads to evaporation of the solvent with low boiling point in the composite fiber. The precursor is moved to the outside of the composite fiber, Forming nanocrystals and simultaneously removing the polymer to form a porous one-dimensional tube composed of a heterogeneous complex of metal oxide (SnO ₂ ) - metal oxide (NiO)

The resulting metal oxide precursor (SnCl ₂ , NiCl ₂ ) / polymer (PVP) composite fiber was rapidly heated at a rate of 10 ° C. per minute and heat-treated at 700 ° C. for 2 hours to finally obtain a metal oxide (SnO ₂ ) A porous one-dimensional tube composed of a heterogeneous complex of oxide (NiO) was obtained.

Mixing a porous one-dimensional tube composed of a heterogeneous complex of a metal oxide (SnO ₂ ) and a metal oxide (NiO) with a binder and a conductive material, and slurry casting the mixture on a current collector to prepare a negative electrode for a secondary battery

In the present invention, 10 wt% of a negative electrode active material, 80 wt% of poly (acrylic acid), and 50 wt% of sodium carboxymethylcellulose (50/50 w / w) %, And Super-p carbon particles of 10 wt% were mixed, slurry-coated on a Cu current collector substrate, dried and rolled, and then punched to a predetermined size to prepare a negative electrode.

Comparative Example 2: Secondary battery anode active material containing nanoparticles in which two kinds of metal oxides (SnO ₂ , NiO) were simply mixed

- An anode active material consisting of 80 wt% of a negative electrode active material, a mixture of poly (acrylic acid) and sodium carboxymethyl cellulose (NiO), and a metal oxide (SnO ₂ , NiO) Sodium Carboxymethylcellulose) 10 wt% of a mixed binder (50/50 w / w) and 10 wt% Super-p carbon particles were mixed and slurry coated on a copper current collector substrate, dried and rolled, Pouching to produce a negative electrode.

3 (a) is a photograph showing a scanning electron microscope (FEI company, Nova 230) of a polymer-mixed metal oxide precursor (SnCl ₂ , NiCl ₂ ) / polymer (PVP) according to Example 1 of the present invention FIG.

As shown in FIG. 3 (a), a metal oxide precursor (SnCl ₂ , NiCl ₂ ) / polymer (PVP) composite fiber having a diameter of 300 to 500 nm was obtained.

As shown in FIG. 3 (b), a porous one-dimensional tube composed of a heterogeneous complex of a metal oxide (SnO ₂ ) -metal oxide (NiO) having a diameter of 200 to 400 nm was obtained.

4 is a diagram showing an X-ray diffraction pattern (RIGAKU, D / MAX-250) of a porous one-dimensional tube composed of a heterogeneous complex of metal oxide (SnO ₂ ) -metal oxide (NiO) according to Example 1 of the present invention .

As can be observed from the crystal pick of FIG. 4, it can be seen that different kinds of metal oxides (SnO ₂ , NiO) are well formed.

5 shows a porous one-dimensional tube composed of a heterogeneous complex of metal oxide (SnO ₂ ) -metal oxide (NiO) coated with metal (Ag) nanoparticles prepared according to Example 1 of the present invention, and (b) (Transmission Electron Microscope, TEM, JEOL 3010).

Referring to FIG. 5, it can be seen that the metal oxide (SnO ₂ , NiO) has a size distribution of 5 nm to 20 nm. It is also confirmed that the metal (Ag) nanoparticles have a size distribution of 8 nm to 10 nm. Also, it can be seen that the fine pores having an average diameter of 2 nm to 5 nm are well developed over the entire one-dimensional tube, which is very advantageous for penetration of the electrolyte solution.

6 is a transmission electron microscope (SEM) image of a porous one-dimensional tube composed of a heterogeneous complex of a metal oxide (SnO ₂ ) -metal oxide (NiO) coated with metal (Ag) nanoparticles prepared according to Example 1 of the present invention Dark Field Image, JEOL 3010), and (b) the silver nanoparticles are uniformly coated on the surface by energy spectral analysis thereof. Referring to FIG. 6 (b), it can be seen that Ag nanoparticles are uniformly coated on the surface of a porous one-dimensional tube composed of a heterogeneous complex of metal oxide (SnO ₂ ) -metal oxide (NiO).

Then, LiPF ₆ is added to the nonaqueous electrolyte solution prepared by mixing ethylene carbonate and diethyl carbonate at a volume ratio of 30:70 to prepare a 1M LiPF ₆ nonaqueous electrolyte solution. A lithium metal foil was used as a counter electrode. A polyolefin separator was interposed between both electrodes, and an electrolyte was injected thereinto to prepare a coin type secondary battery. The cell characteristics of the secondary batteries manufactured according to the examples and the comparative examples were measured in a charge / discharge device (Wonatech, WBCS3000S) at a constant temperature of 25 ° C.

7 is a cyclic voltammogram of a porous one-dimensional tube composed of a heterogeneous complex of metal oxide (SnO ₂ ) -metal oxide (NiO) coated with metal (Ag) nanoparticles prepared according to Example 1 of the present invention. ). As can be seen from FIG. 7, a porous one-dimensional tube made of a heterogeneous complex of a metal oxide (SnO ₂ ) -metallic oxide (NiO) coated with the metal (Ag) nanoparticles produced has a dislocation in which SnO ₂ and NiO react with lithium ions V). It can be seen that the synthesized porous one-dimensional tube has phases of SnO ₂ and NiO.

8 (a) is a graph showing initial cycle characteristics of a secondary battery manufactured according to Example 1, Comparative Example 1, and Comparative Example 2 of the present invention.

8 (a), a porous one-dimensional tube composed of a heterogeneous complex of a metal oxide (SnO ₂ ) -metal oxide (NiO) coated with 3 wt% of metal (Ag) nanoparticles according to Example 1, A porous one-dimensional tube composed of a heterogeneous complex of a metal oxide (SnO ₂ ) -metallic oxide (NiO) according to Example 1 and a nanoparticle in which two kinds of metal oxides (SnO ₂ , NiO) The graph shows the initial cycle characteristics of a lithium half cell employing a secondary battery anode made by mixing with a conductive material and slurry casting on a current collector. As a result of initial charging and discharging at 50 mA g ^{- 1} , the charged light discharge capacities of Example 1 were 1715 mAh g ^-1 and 1335 mAh g ^-1 , respectively. The charge discharge capacity of Comparative Example 1 was 1636 mAh g ^-1 , 1266 mAh g- ¹ , and the charge-discharge capacity of Comparative Example 2 was 1473 mAh g ^-1 and 886 mAh g ^-1 , respectively. The initial coulombic efficiency of Example 1, Comparative Example 1, 78%, 77%, and 60% of the initial coulombic efficiency. The conversion efficiencies of Example 1 and Comparative Example 1 were significantly higher than those of Comparative Example 2 because SnO ₂ and NiO were continuously bound in a nanogram form to form a tube and exhibited a catalytic effect of decomposing Li ₂ O during discharge Respectively. As the comparative example 2 shows a low conversion efficiency, it can be seen that the mixing of simple nanoparticles does not exhibit such a catalytic effect.

FIG. 8 (b) is a graph showing rate characteristics of a secondary battery manufactured according to Example 1, Comparative Example 1, and Comparative Example 2. FIG.

Referring to FIG. 8 (b), it can be seen that Example 1 exhibits excellent rate characteristics compared to Comparative Example 1 and Comparative Example 2. This is because the Ag nanoparticles are coated on the surface of the porous one-dimensional tube and the electrical conductivity is greatly improved.

9 shows life characteristics obtained up to 500 cycles of a secondary battery produced according to Example 1, Comparative Example 1 and Comparative Example 2

To 100 cycles of charging and discharging current 500 mA g ^- fixed to the ^first and after that was being tested was fixed to 1000 mA g ^-1 in Example 1 showed a very stable capacity maintenance rate after 300 cycles passed. On the contrary, Comparative Example 1 (a cathode using a porous one-dimensional tube composed of a heterogeneous composite without Ag nanoparticles coated thereon as a negative electrode active material) showed a drastic decrease in capacity after 300 cycles and Comparative Example 2 (metal oxide (SnO ₂ , NiO) And a negative electrode using simple mixed nanoparticles as a negative active material) showed a decrease in capacity after several cycles. As a result, the porous one-dimensional tube structure composed of the heterogeneous composite employed in Example 1 and Comparative Example 1 effectively relaxed the volume expansion of the negative active material at the time of charging and discharging. Thus, the negative active material of Comparative Example 2 It can be seen that the life characteristics are greatly improved. Also, by comparing Example 1 with Comparative Example 1, it can be seen that the lifetime characteristics can be remarkably improved by increasing the electrical conductivity of a porous one-dimensional tube composed of a heterogeneous complex by coating of highly conductive Ag nanoparticles.

When a one-dimensional porous nanotube composed of a metal-metal oxide or a metal oxide-metal oxide-coated complex of metal nanoparticles coated with metal nanoparticles is used as a negative electrode active material for a secondary battery 1) High conductivity metal nanoparticles have high electric conductivity And 2) a one-dimensional porous nanotube structure that can effectively alleviate the volume expansion of the transition metal oxide upon charging, resulting in excellent lifetime characteristics; and 3) a metal oxide nanoparticle or a metal oxide-metal nanoparticle The present invention can provide a next generation negative electrode active material and a secondary battery negative electrode using the same, in which Li ₂ O generated during the charging process is decomposed and the irreversible capacity is drastically lowered, thereby remarkably improving the conversion efficiency.

Particularly, the one-dimensional porous nanotubes composed of the metal nanoparticles-coated metal-metal oxide or metal oxide-metal oxide composite prepared according to the present invention can be used as a one-dimensional structure It has a high economical efficiency because it is produced by simple calcination in air and then introduced with high conductivity metal nanoparticles through a simple solution process at room temperature.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and similarities. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

100: metal or metal oxide precursor / polymer composite fiber
200: heterogeneous composite porous nanotubes
300: Heterogeneous porous nanotubes coated with metal nanoparticles
310: metal nanoparticles

Claims (27)

(Ni) - a first metal oxide (SnO ₂ ) or a second metal oxide (NiO) - a first metal oxide (SnO ₂ ) or a second metal oxide (NiO) in which different kinds of nanoparticles or different types of nano- ₂ ), < / RTI >
As the metal (Ni) binds to the first metal oxide (SnO ₂ ) in the form of nanoparticles, the catalyst exhibits catalytic properties to decompose Li ₂ O generated during the charging process to increase the conversion efficiency, (NiO) is bound to the first metal oxide (SnO ₂ ) in the form of nanoparticles, the catalyst exhibits catalytic properties to decompose Li ₂ O generated during the charging process, thereby increasing the conversion efficiency of the porous one-dimensional nanotube. delete delete The method according to claim 1,
A porous one-dimensional nanotube characterized in that metal nanoparticles are bound to a surface and an inner surface of a tube composed of a heterogeneous complex. 5. The method of claim 4,
In the heterogeneous complex of the metal (Ni) and the first metal oxide (SnO ₂ ), the relative weight ratios of the metal (Ni), the first metal oxide and the metal nano-particles are 10-89.9 wt% And 0.1 to 5 wt%, the sum of the relative weight ratios is 100 wt%
In a heterogeneous composite of the second metal oxide (NiO) - the first metal oxide (SnO ₂ ), the second metal oxide (NiO) has a relative weight ratio of 10 to 89.9 wt% relative to the first metal oxide (SnO ₂ ) , The relative weight ratio of the metal nanoparticles is 0.1 to 5 wt%, and the sum of the relative weight ratios is 100 wt%. 5. The method of claim 4,
The metal nanoparticles are Ir, Os, Po, Rh, Ru, Pt, Pd, Au, and include the alloys thereof naejineun metal selected from Ag, increases the electrical conductivity of said porous one-dimensional nanotubes, or Li ₂ O Thereby increasing the conversion efficiency of the porous one-dimensional nanotube. 5. The method of claim 4,
Wherein the size of the metal nanoparticles is in the range of 0.1 to 20 nm. The method according to claim 1,
Wherein the length of the porous one-dimensional nanotube is in the range of 1 to 1000 mu m. The method according to claim 1,
Wherein the outer diameter ratio of the tube to the length of the tube is in the range of 5 to 5,000. The method according to claim 1,
Wherein the size of the heterogeneous nanoparticle or the heterogeneous nano-grain is in the range of 0.1 to 200 nm. The method according to claim 1,
Wherein the micropores have micropores having an average diameter in the range of 0.1 to 10 nm. The negative active material for a secondary battery according to any one of claims 1 to 11, wherein the porous one-dimensional nanotube comprises the porous one-dimensional nanotube. The negative electrode for a secondary battery according to claim 12, further comprising a binder and a conductive material in the negative electrode active material for a secondary battery. 14. The method of claim 13,
The binder and the conductive material are mixed with the porous one-dimensional tube,
Wherein the porous one-dimensional tube in which the binder and the conductive material are mixed is formed by slurry casting on the current collector. A method for producing a porous nanotube negative electrode active material for a secondary battery,
(a) a metal precursor (Ni precursor) - a first metal oxide precursor (SnCl ₂ ) or a second metal oxide precursor (NiCl ₂ ) - a first metal oxide precursor (SnCl ₂ ) , A metal precursor (Ni precursor) - a composite metal in which a first metal oxide precursor (SnCl ₂ ) and a polymer are mixed or a second metal oxide precursor (NiCl ₂ ) - a first metal oxide precursor (SnCl ₂ ) ; And
(b) Rapidly heat treating the composite fiber to evaporate the solvent in the composite fiber, and the precursor is moved to the outside of the composite fiber to reduce or oxidize to form nanoparticles or nano-grains. At the same time, the polymer is removed, Forming a porous one-dimensional tube composed of a heterogeneous complex of a first metal oxide (SnO ₂ ) or a second metal oxide (NiO) - a first metal oxide (SnO ₂ )
Lt; / RTI >
As the metal (Ni) binds to the first metal oxide (SnO ₂ ) in the form of nanoparticles, the catalyst exhibits catalytic properties to decompose Li ₂ O generated during the charging process to increase the conversion efficiency, (NiO) is bound to the first metal oxide (SnO ₂ ) in the form of nanoparticles, the catalyst exhibits catalytic properties and decomposes Li ₂ O generated during the charging process to increase the conversion efficiency. Method of manufacturing nanotube negative electrode active material. 16. The method of claim 15,
(c) uniformly coating the metal nanoparticles on the inner and outer surfaces of the porous one-dimensional tube formed of the heterogeneous complex through metal-mirror reaction
The method of claim 1, wherein the porous nanotube negative electrode active material is selected from the group consisting of: 17. The method of claim 16,
Wherein the metal nanoparticles comprise a metal selected from the group consisting of Ir, Os, Po, Rh, Ru, Pt, Pd, Au and Ag or alloys thereof. 17. The method of claim 16,
Wherein the size of the metal nanoparticles is in the range of 0.1 to 100 nm. ≪ RTI ID = 0.0 > 11. < / RTI > 17. The method of claim 16,
The step (c)
Dispersing a metal precursor (Ni precursor) or a second metal oxide precursor (NiCl ₂ ) in a solution prepared by dispersing the formed porous one-dimensional tube in ethanol;
Heating the solution and mixing the heated solution with an amine-based reducing agent;
Stirring the mixed solution while heating; And
Filtering the solution;
Wherein the porous nanotube negative electrode active material is a mixture of the porous nanotubes. 16. The method of claim 15,
(d) mixing a porous one-dimensional tube composed of the heterogeneous composite with a binder and a conductive material, and slurry casting the mixture on a current collector to prepare a negative electrode for a secondary battery
The method of claim 1, wherein the porous nanotube negative electrode active material is selected from the group consisting of: 16. The method of claim 15,
The solvent is soluble in both the polymer and the metal precursor (Ni precursor) - the first metal oxide precursor (SnCl ₂ ) or the polymer and the second metal oxide precursor (NiCl ₂ ) - the first metal oxide precursor (SnCl ₂ ) Wherein the porous nanotube anode active material is a mixture of two or more kinds of solvents having a boiling point. 16. The method of claim 15,
The polymer is contained in the solvent so as to be 5 to 15% by weight based on the solvent,
Wherein the metal precursor (Ni precursor) - the first metal oxide precursor (SnCl ₂ ) or the polymer and the second metal oxide precursor (NiCl ₂ ) - the first metal oxide precursor (SnCl ₂ ) is 5 to 15 wt% Wherein the porous nanotube negative electrode active material is contained in the solvent. 16. The method of claim 15,
The step (a)
Wherein the metal precursor (Ni precursor) - the first metal oxide precursor (SnCl ₂ ), the polymer and the solvent are mixed or the second metal oxide precursor (NiCl ₂ ) - the first metal oxide precursor (SnCl ₂ ) And the solution is electrospun through a device composed of a spray nozzle, a high voltage generator, and a conductive current collector connected to a metering pump capable of quantitatively injecting a solution mixed with the solvent. The porous nanotube negative electrode active material for a secondary battery Gt; 16. The method of claim 15,
The step (a)
Wherein the metal precursor (Ni precursor) - the first metal oxide precursor (SnCl ₂ ), the polymer and the solvent are mixed or the second metal oxide precursor (NiCl ₂ ) - the first metal oxide precursor (SnCl ₂ ) And the solution mixed with the solvent is electrospun through at least one injection nozzle. The method for manufacturing a porous nanotube negative electrode active material for a secondary battery according to claim 1, 16. The method of claim 15,
In the step (b), for the rapid thermal annealing, 10 To 100 Lt; 0 > C to 1000 < 0 > Lt; 0 > C for 30 minutes to 2 hours. The method for manufacturing the porous nanotube anode active material for secondary batteries according to claim 1, 16. The method of claim 15,
The step (b)
The porous nanotube anode active material for a secondary battery according to any one of claims 1 to 3, wherein the porous single-walled tube is made of the heterogeneous composite by performing an oxidative heat treatment for heat-treating the composite fiber in an atmospheric or oxygen atmosphere. 26. A method for producing a cathode for a secondary battery, comprising mixing a binder and a conductive material in the porous hybrid nanotube anode active material produced by the method of any one of claims 15 to 26 and slurry casting the mixture on a current collector to form a cathode for a secondary battery Forming step
Wherein the negative electrode comprises a positive electrode and a negative electrode.

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