KR101108980B1 - Micro-rod and material containing the same, and method for preparing micro-rod and nano-powder - Google Patents

Abstract

The present invention relates to a microrod having a large specific surface area and a well-developed pore structure due to the regular aggregation of nanoparticles, a method for producing the same, a material containing the same, and a method for preparing a nanopowder using the microrod, and the average size thereof. Is composed of at least one of the nanoparticles of the metal nanoparticles and metal oxide nanoparticles of 5 to 100 nm, the width is 50 to 1000 nm and the long-to-short ratio, the ratio of the length to the width is 1.5 or more and 200 or less Characterized by microrods and materials containing them. The microrods to nanopowders according to the present invention may be used in various applications such as electrode active materials for secondary batteries, electrode materials for electrochemical capacitors, electrode materials for fuel cells, sensing materials for gas sensors, and catalysts.

Metals, metal oxides, nanoparticles, electrospinning, polymers, nanofibers, microrods, nanopowders

Description

MICRO-ROD AND MATERIAL CONTAINING THE SAME, AND METHOD FOR PREPARING MICRO-ROD AND NANO-POWDER}

The present invention relates to a microrod having a large specific surface area and well developed pore structure due to the regular aggregation of nanoparticles, a method for producing the same, a material containing the same, and a method for preparing a nanopowder using the microrod.

Recently, research on materials having a particle size of nanometer (nm) has been actively conducted. In particular, these nano-sized materials have a large specific surface area, a large surface area / volume ratio, and a porous structure, so that gas diffusion is excellent and penetration characteristics of the liquid electrolyte are excellent. Therefore, these nano-sized materials may be used in various applications such as gas sensors, supercapacitors, pseudo-reversible capacitors (Psuedocapacitor), secondary batteries, fuel cells, catalyst materials, and the like.

There are a variety of approaches for preparing nano-sized particles (ie nanoparticles).

In one method, the nanoparticles are mixed through a calcination process, a sintering process, and a micro-bead milling process in which raw material powders are mixed, and organic substances contained in the mixed powder are vaporized and removed. There is a solid phase reaction method to prepare. However, this solid phase reaction method has a large powder size, which is generally difficult to produce nanoparticles of 100 nm or less. In addition, since the bulk material produced at high synthesis temperature is mechanically pulverized to make it small, the particle shape is uneven, and a long grinding process is required to obtain fine powder.

Unlike the solid phase reaction method, the co-precipitation method, which is a wet manufacturing method, has an advantage of preparing a powder having a very small particle size compared to the powder prepared by the solid phase reaction. In addition, the manufacturing process is simple because there is no need for repetitive calcination and grinding processes required in the solid phase reaction method. The coprecipitation method is a method of preparing oxide nanoparticles by precipitating a nitride or chloride contained in a raw material as a hydroxide in a basic coprecipitation solution and subjecting it to heat treatment. For this purpose, it is important to control conditions such as temperature, stirring conditions, and pH of the coprecipitation solution. In particular, when manufacturing a four-component or more complex metal oxide, it is difficult to meet the exact stoichiometric ratio (complex stoichiometric ratio) due to complex process conditions, there is a disadvantage that it is difficult to manufacture a nanoparticle having a uniform particle shape of 20 nm or less. In particular, it is possible to produce fine nanoparticles by a wet manufacturing method, but when the nanoparticle size is small, there is agglomeration between non-uniform particles. In addition, the manufacturing process takes a lot of time.

The present invention has been made to solve these conventional problems, the object of the present invention,

First, it provides a micro rod with agglomeration between fine nanoparticles and well-developed pore structure and its manufacturing method,

Second, it provides a way to easily manufacture these microrods in high volumes with high production yields.

Third, to provide a general manufacturing method for the nanoparticles constituting the microrods is not limited to a specific material, but may be made of various kinds of metals, alloys, metal oxides and / or composite metal oxides,

Fourthly, the present invention provides a method for manufacturing microrods and nanopowders, which can be easily mass-produced with a multicomponent composite metal oxide at a desired composition ratio.

Fifth, to provide a method for obtaining nanopowder from the microrods.

These objects can be achieved by the following configuration of the present invention.

(1) comprises at least one nanoparticles of metal nanoparticles and metal oxide nanoparticles having an average size of 5 to 100 nm, and has a long and short ratio of 50 to 1000 nm in width and a ratio of length to width; 1.5 or more and 200 or less micro rod.

(2) A material containing the microrods according to (1) above.

(3) preparing a spinning solution in which at least one of a metal precursor and a metal oxide precursor are mixed with a polymer;

Spinning the spinning solution onto a fiber under an electric field to form a composite fiber in which at least one of the metal precursor and the metal oxide precursor and the polymer are mixed;

Heat treating the composite fiber to obtain nanofibers including at least one nanoparticles of metal nanoparticles and metal oxide nanoparticles from which the polymer is melt-removed from the composite fiber;

And grinding the nanofibers to obtain a microrod including at least one nanoparticle among the metal nanoparticles and the metal oxide nanoparticles.

(4) preparing a spinning solution in which at least one of a metal precursor and a metal oxide precursor are mixed with a polymer;

Spinning the spinning solution onto a fiber under an electric field to form a composite fiber in which at least one of the metal precursor and the metal oxide precursor and the polymer are mixed;

Heat treating the composite fiber to obtain nanofibers including at least one nanoparticles of metal nanoparticles and metal oxide nanoparticles in which the polymer is melted away from the composite fiber;

Firstly crushing the nanofiber to obtain a microrod including at least one nanoparticle of the metal nanoparticles and the metal oxide nanoparticles;

The microrods are pulverized second to obtain nanopowders comprising at least one metal nanoparticles of the metal nanoparticles or at least one metal oxide nanoparticles of the metal oxide nanoparticles. Manufacturing method.

The microrod manufactured by the present invention has a small and uniform contact of fine nanoparticles, so that the contact resistance between particles is small, the specific surface area is large, and the pore structure between particles is well developed. Accordingly, gas diffusion into the microrods is quick and the liquid electrolyte penetrates well. Therefore, the microrod according to the present invention may be applied to a sensing material for a gas sensor, an electrode active material for a secondary battery (cathode active material and a cathode active material), an electrode material for a fuel cell, an electrode material for an electrochemical capacitor, a catalyst material, and the like.

In addition, since sol-gel reaction is involved in the process of manufacturing a composite fiber by spinning, it is possible to easily prepare metals, metal oxides, and composite metal oxides ranging from two-component to multi-component systems by combining various precursors. . Accordingly, metal, metal oxide and / or composite metal oxide microrods having various characteristics can be easily manufactured in large quantities according to the required specifications of the application field.

In addition, depending on the degree of pulverization of the nanofibers, it is possible to obtain the results of various sizes ranging from the shape of the microrods in which the nanofibers are shortly cut to the ultrafine nanoparticles.

In addition, the nanoparticles composed of a metal, an alloy, a metal oxide, and / or two or more composite metal oxides may have a crystalline structure, an amorphous structure, or a structure in which crystalline and amorphous mixtures, depending on the heat treatment temperature conditions. Accordingly, the optimum crystal structure can be easily implemented according to the required specifications of the application field.

The present invention heat-treated a composite fiber of one or more metal precursors and / or one or more metal oxide precursors and polymers spun into fibrous to obtain nanofibers comprising nanoparticles, and then pulverize the nanofibers according to the degree of grinding It provides materials of various sizes, from microrods in the form of short broken fibers to nanopowders to nanoparticles (see FIG. 1).

Micro-rod according to the present invention is made of nanoparticles, characterized in that the 50 to 1000 nm in width and the ratio of the long and short ratio, the ratio of the length to the width is 1.5 to 200 or less. Here, the average size of the nanoparticles is 5 ~ 100 nm. In addition, the nanoparticles are (1) metal nanoparticles made of one or two or more metals, or (2) two or three or more metal oxide nanoparticles made of one or two or more metal oxides. Or (3) the metal nanoparticles of (1) and the metal oxide nanoparticles of (2) may be mixed.

The micro rod is a short break of the nanofibers having a diameter of 50 ~ 1000 nm made of any one of the nanoparticles (1) to (3).

In the microrod according to the present invention, since the fine nanoparticles are uniformly and regularly aggregated, the contact resistance between particles is small, the specific surface area is large, and the pore structure between the particles is well developed. In this regard, pores having an average size distribution of 1 to 50 nm are formed between the metal nanoparticles constituting the microrod, between the metal oxide nanoparticles, or between the metal nanoparticle and the metal oxide nanoparticles. It is preferable that it is formed. This is to allow gas diffusion into the microrods to occur quickly or to permeate the liquid electrolyte well.

The metal nanoparticle is any one selected from the group consisting of Pt, Au, Ag, Li, Si, Mn, Fe, Mg, Ca, Sn, Ti, Ni, Co, Cu, Zn, In, Mo, W, Ir and Ru It may be a nanoparticle consisting of one metal or two or more alloys. However, the present invention does not limit the type of the metal nanoparticles.

In addition, the metal oxide nanoparticles are (1) SnO ₂ , TiO ₂ , Fe ₂ O ₃ , Fe ₃ O ₄ , CoO, Co ₃ O ₄ , CaO, MgO, CuO, ZnO, In ₂ O ₃ , NiO, MoO ₃ , MnO ₂ , WO ₃ , RuO ₂ , IrO ₂ and V ₂ O ₅ any one metal oxide selected from the group consisting of or nanoparticles consisting of two or more complex metal oxides, or (2) Zn ₂ SnO ₄ , CoSnO ₃ , Ca ₂ SnO ₄ , CaSnO ₃ , ZnCo ₂ O ₄ , Co ₂ SnO ₄ , Mg ₂ SnO ₄ , Mn ₂ SnO ₄ , CuV ₂ O ₆ , NaMnO ₂ and NaFeO ₂ Or (3) Li ₄ Ti ₅ O ₁₂ , LiCoO ₂ , LiNiO ₂ , LiNi _1-y Co _y O ₂ (y = 0.1 to 0.9), LiMn ₂ O ₄ , Li [Ni _1/2 Mn _1/2 ] O ₂ and LiFePO ₄ nanoparticles consisting of any one of the Li-containing transition metal oxide selected from the group, or (4) Mg ²⁺ , Al ³⁺ , Ti ⁴⁺ , Zr ^{4+ in} place of Li LiFePO ₄ , LiMnPO ₄ , LiNiPO ₄ doped with at least one of Nb ⁵⁺ and W ⁶⁺ to 1 at% or less , LiCoPO ₄ , LiAl _0.05 Co _0.85 Ni _0.15 O ₂ , Li [Ni _1/3 Co _1/3 Mn _1/3 ] O ₂ , Li [Ni _1/2 Mn _1/2 ] O ₂ , LiNi _1-x Co (5) Pt-RuO ₂ , Ni-Y _0.08 or nanoparticles consisting of any one of Li-containing composite metal oxides selected from the group consisting of _x O ₂ and LiNi _1-x Ti _{x / 2} Mg _{x / 2} O ₂ Zr _0.92 O ₂ or Pt-Y _0.08 Nanoparticles consisting of complex metal oxides, which are complexes of metals and metal oxides such as Zr _0.92 O ₂ , or (6) Y _0.08 Zr _0.92 O ₂ , La _1-x Sr _x CoO ₃ (x = 0.1 to 0.9), La _0.8 Sr _0.2 Fe _0.8 Co _0.2 O ₃ , La _1-x Sr _x MnO ₃ (x = 0.1 to 0.9), La _1-x Sr _x FeO ₃ (x = 0.1 to 0.9) And La _0.8 Sr _0.2 Fe _0.8 Co _0.2 O _{3 It} may be a nanoparticle consisting of any one composite metal oxide selected from the group consisting of. However, the present invention does not limit the type of the metal oxide nanoparticles.

When the metal oxide nanoparticles include two or more kinds of metal oxides, the metal oxide nanoparticles are formed of a solid solution of two or more kinds of metal oxides, a mixed phase of two or more kinds of metal oxides separated from phases, and two or more kinds of metal oxides. It may have a microstructure of at least one of the compounds.

In addition, the nanoparticles (hereinafter, collectively referred to as "metal nanoparticles" and "metal oxide nanoparticles") may have a crystalline structure, an amorphous structure, or a structure in which crystalline and amorphous are mixed depending on the heat treatment temperature. Accordingly, the microrod according to the present invention can easily optimize the crystal structure to meet the specifications required in the application field.

The present invention also provides a material containing such a microrod.

Examples of such a material include an electrode active material for a secondary battery, an electrode material for an electrochemical capacitor, an electrode material for a fuel cell, a sensing material for a gas sensor, or a catalyst. For example, when the microrod according to the present invention is used as an electrode active material for a secondary battery, a coating composition in which the microrod, the conductive material (for example, carbon black), and the binder are mixed is coated on the current collector by a doctor blade method or the like. The active material thin layer can be formed. In addition, for the application to electrode materials for electrochemical capacitors, a current collector is coated with a coating composition in which the microrod having an amorphous structure, a conductive material (for example, carbon black), and a binder (for example, PTFE, PVDF, etc.) are mixed. It can also apply | coat by the doctor blade method etc. on this, and can form the electrode thin layer for supercapacitors.

On the other hand, the manufacturing method of the microrod according to the present invention is largely (1) preparing a spinning solution, (2) forming a composite fiber by spinning, (3) manufacturing a nanofiber by heat treatment of the composite fiber, (4) It can be divided into the manufacturing steps of the microrods by primary grinding. In addition, the present invention may further comprise the step of obtaining a nano-powder by secondary grinding the microrod obtained above. Hereinafter, each step will be described in detail.

Preparation of Spinning Solutions

First, for spinning, a spinning solution in which at least one metal precursor and / or at least one metal oxide precursor, a polymer and a solvent are mixed is prepared.

Here, the metal precursor is a precursor capable of forming a metal through heat treatment in a reducing atmosphere, for example Ir, Ru, Pt, Au, Ag, Li, Si, Mn, Fe, Mg, Ca, Sn, Ti, Ni, One or more precursors containing Co, Cu, Zn, In, Mo, or W ions may be included. However, the present invention is not limited to the kind of the metal precursor.

In addition, the metal oxide precursor is a precursor capable of forming a metal oxide through heat treatment in air or under an oxidizing atmosphere, for example, Li, Si, Mn, Fe, Mg, Ca, Sn, Ti, Ni, Co, Cu, Zn At least one precursor containing In, Mo, V, W, P, Ir, Ru, Na, Al, Zr, Pt, Nb, Y, La, or Sr ions may be included. However, the present invention is not limited to the kind of the metal precursor.

The polymer increases the viscosity of the spinning solution to form a fibrous phase upon spinning, and serves to control the structure of the spun fiber by compatibility with the metal precursor and / or the metal oxide precursor. Such polymers include polyvinylacetate, polyurethane, polyurethane copolymers, polyetherurethanes, cellulose acetate and cellulose derivatives such as cellulose acetate butyrate and cellulose acetate propionate, polymethylmethacrylate (PMMA), polymethylacrylic Latex (PMA), polyacrylic copolymer, polyvinylacetate copolymer, polyvinyl alcohol (PVA), polyperfuryl alcohol (PPFA), polystyrene (PS), polystyrene copolymer, polyethylene oxide (PEO), polypropylene oxide ( PPO), polyethylene oxide copolymer, polypropylene oxide copolymer, polycarbonate (PC), polyvinyl chloride (PVC), polycaprolactone, polyvinylpyrrolidone (PVP), polyvinyl fluoride, polyvinylidene paste Luolide copolymers, polyacrylonitrile, polyamides, pitch and phenolic resins (phenol resin) may be at least one selected from the group consisting of. However, the present invention is not limited to the types of polymers listed above.

The solvent includes water, ethanol, THF (Tetrahydrofuran), DMF (N, N'-dimethylformamide), DMAc (N, N'-Dimethylacetamide), NMP (N-methylpyrrolidone), Acetonitrile (Acetonitrile) Polar solvents and nonpolar solvents such as toluene, chloroform, methylene chloride, benzene and xylene may be used. However, the present invention is not limited thereto.

Looking at an example of the spinning solution manufacturing process, first, polyvinylacetate having excellent affinity with a metal oxide precursor is dissolved in a dimethylformamide solvent to prepare a 5-20 wt% polymer solution. In this case, the polyvinyl acetate preferably has a weight average molecular weight of 500,000 ~ 1,500,000 g / mol. Next, a metal oxide precursor is added to the polymer solution in an amount of 1 to 60 wt% based on the polymer solution, acetic acid is added as a catalyst in an amount of 0.01 to 60 wt% based on tin acetate, and then, at room temperature, 1 Let it react for 10 hours. If necessary, add Cetyltrimethyl Ammonium Bromide (CTAB) and stir for a few minutes. Here, CTAB serves as an additive to smooth the radiation by adjusting the charge characteristics of the metal oxide precursor.

Formation of Composite Fibers by Spinning

Next, the spinning solution is spun into fibers under an electric field to form a composite fiber in which the at least one metal precursor and / or the at least one metal oxide precursor and the polymer are mixed. When spinning, the composite fiber is formed through phase separation or mutual mixing between the one or more metal precursors and / or the one or more metal oxide precursors and the polymer.

In this case, the radiation may be radiation by any one method selected from among electro-spinning, melt-blown, flash spinning, and electrostatic melt-blown methods. Can be.

For example, a voltage of 5 to 30 kV may be applied during electrospinning, and the discharge rate of the spinning solution may be adjusted to 10 to 50 μl / min to prepare a large amount of ultrafine composite fibers having a diameter of 50 to 1000 nm. Since the sol-gel reaction by electrospinning depends on moisture, the temperature and humidity around the spinning device act as important process variables.

Preparation of Nanofibers by Heat Treatment of Composite Fibers

Next, the composite fiber is heat-treated to obtain nanofibers in which the polymer is melted and removed from the composite fiber. Here, the nanofibers comprise one or more metal nanoparticles and / or one or more metal oxide nanoparticles.

The composite fiber produced in a large amount in the previous step is collected and subjected to a high temperature heat treatment process. At this time, the heat treatment temperature and time are determined in consideration of the crystallization and firing temperature of the metal precursor or metal oxide precursor used. The heat treatment may be performed in a temperature range of 400 ~ 900 ℃ depending on the type of metal precursor or metal oxide precursor. In some cases, nanofibers including nanoparticles having an amorphous structure may be obtained through a low temperature heat treatment at 300 to 400 ° C. In addition, this heat treatment may be performed in air, in an oxidizing atmosphere, in a reducing atmosphere or in a vacuum.

The nanofibers thus obtained are composed of ultrafine nanoparticles, so that the specific surface area is large and the reaction area is maximized. Here, the average diameter of the nanofibers is 50 ~ 1000 nm, the average size of the nanoparticles constituting the nanofibers is 5 ~ 100 nm, the pores of 1 ~ 50 nm size are formed between the nanoparticles It is preferable. The size of these nanoparticles is changed by the heat treatment temperature. If necessary, it is also possible to produce microfibers having a diameter of 1 to 3 µm by controlling the viscosity of the polymer and the solvent.

The nanoparticles constituting the nanofibers may be formed of a composite metal oxide, which is a metal, an alloy, a metal oxide, or a composite of two or more metal oxides, depending on the kind of precursor used and the heat treatment atmosphere. For example, nanoparticles made of metals or alloys are obtained through heat treatment under a reducing atmosphere (N ₂ / H ₂ , CO, N ₂ , or Ar gas atmosphere). Here, the alloy includes SnSi, SnCo, Zn ₂ Sn, SnP, and the like, without limiting the specific alloy ratio. In addition, nanoparticles made of metal oxides or composite metal oxides are obtained through heat treatment in air or in an oxidizing atmosphere.

In addition, looking at the microstructure of the nanoparticles made of the composite metal oxide, the nanoparticles of the solid solution of two or more metal oxides, phase separation of the two or more metal oxide phases according to the relative ratio of the precursor used It may comprise a compound consisting of a mixed phase and / or two or more metal oxides. In other words, if the relative ratio of two or more precursors is within the solubility limit, the nanoparticles are made of a solid solution of two or more metal oxides. In addition, when the relative ratio exceeds the solubility limit, phase separation occurs at a ratio exceeding the solubility limit, and the nanoparticles are composed of a mixed phase of two or more metal oxide phases separated from the solid solution. In addition, when the two or more precursors used do not form a solid solution with each other, the nanoparticles are composed of a mixed phase of two or more metal oxide phases separated from each other. Furthermore, when two or more precursors used have a specific compositional ratio, the nanoparticles may be composed of a new compound having a specific compositional ratio. In the present invention, the term "composite metal oxide" is also a concept including a complex of a metal and a metal oxide. Thus, not only the complex metal oxide complex of two or more metal oxides, but also the fine structure of the complex metal oxide complex of the metal and the metal oxide may be composed of a solid solution, a mixed phase and / or a compound of the metal and the metal oxide.

Manufacture of Micro Rods

Next, the nanofibers obtained above are first ground to obtain a microrod. Here, the microrods comprise one or more metal nanoparticles and / or one or more metal oxide nanoparticles. In the present invention, "nano" of the term "nanofiber" means the diameter of the fiber, and "micro" of the term "microrod" means the length of the rod.

The primary grinding may be performed by ball milling or attrition milling after ultrasonic grinding. Through primary grinding, the nanofibers are finely ground. Milling is preferably carried out for 5 to 24 hours for uniform grinding, and after grinding, microrods having a length and shortening ratio of 50 to 1000 nm and a length-to-width ratio of 1.5 to 200 are formed. It is preferable that the length is 100 nm-10 micrometers. In particular, the microrod is composed of fine nanoparticles of an average size of 5 ~ 100 nm.

Preparation of Nano Powder

Next, the microrods obtained above are pulverized second to obtain nanopowders. Here, the nano powder comprises at least one metal nanoparticles of the metal nanoparticles or at least one metal oxide nanoparticles of the metal oxide nanoparticles. That is, the nanopowder may be one nanoparticle or several nanoparticles may be agglomerated.

The secondary milling may be through microbid milling. Microbead milling is preferably performed for 5 to 24 hours, and after the second grinding, fine nanopowders having a size of 5 to 200 nm, preferably 5 to 100 nm can be obtained.

The constituent components of the nanopowders to the nanoparticles obtained by the present invention are not limited to specific materials such as metals, metal oxides and composite metal oxides. For example, the metal may include Pt, Au, Ag, Ni, Cu, Ti, Sn, Si, and the like, and an alloy such as SnSi, SnCo, Zn ₂ Sn, SnP may be used. The metal oxide may be SnO ₂ , TiO ₂ , Fe ₂ O ₃ , Fe ₃ O ₄ , CoO, Co ₃ O ₄ , CaO, MgO, CuO, ZnO, In ₂ O ₃ , NiO, MoO ₃ , MnO ₂ or WO ₃ and the like, and conductive metal oxides such as RuO ₂ and IrO ₂ may be used. Three-component metal oxide composites (ie composite metal oxides) include Sn _1-x Ti _x O ₂ , (ZnO) _1-x (SnO ₂ ) _x , (CoO) _1-x (SnO ₂ ) _x , (CaO) _1-x (SnO ₂ ) _x , (ZnO) _1-x (CoO) _x , (MgO) _1-x (SnO ₂ ) _x or (MnO) _1-x (SnO ₂ ) _x (where x = 0.01 ~ 0.99) and Zn ₂ SnO ₄ , CoSnO ₃ , Ca ₂ SnO ₄ , CaSnO ₃ , ZnCo ₂ O ₄ , Co ₂ SnO ₄ , Mg ₂ SnO _4, or Mn ₂ SnO ₄ in the form of a compound. In addition, as a four-component metal oxide composite (ie, a composite metal oxide), (ZnO) _x (SnO ₂ ) _y (CoO) _z , (ZnO) _x (SnO ₂ ) _y (CaO) _z , (TiO) _x (SnO ₂ ) _y (CaO) _z , (TiO) _x (SnO ₂ ) _y (ZnO) _z , (MgO) _x (SnO ₂ ) _y (ZnO) _z or (MnO) _x (SnO ₂ ) _y (ZnO) _z ( Here, x + y + z = 1) may be mentioned. Examples of the five-component metal oxide composite include (NiO) _a (ZnO) _b (Fe ₂ O ₃ ) _c (TiO ₂ ) _d (SnO ₂ ) _e (a + b + c + d + e = 1). Can be. In addition, the nano powder to the nanoparticles may be composed of Li ₄ Ti ₅ O ₁₂ utilized as a negative electrode active material for secondary batteries, or V ₂ O ₅ , CuV ₂ O ₆ , NaMnO ₂ , NaFeO ₂ , LiCoO ₂ , LiNiO ₂ , LiNi _1-y Co _y O ₂ , LiMn ₂ O ₄ , Li [Ni _1/2 Mn _1/2 ] O ₂ , LiFePO ₄ , or Ligium Mg ²⁺ , Al ³⁺ , Ti LiFePO ₄ , LiAl _0.05 Co _0.85 Ni _0.15 O ₂ , Li [Ni _1/3 Co _1/3 Mn _1/3 ] doped with ⁴⁺ , Zr ⁴⁺ , Nb ⁵⁺ or W ⁶⁺ to 1 at% or less O ₂ , Li [Ni _1/2 Mn _1/2 ] O ₂ , LiNi _1-x Co _x O ₂ , LiNi _1-x Ti _{x / 2} Mg _{x / 2} O ₂ , LiCoPO ₄ , LiMnPO ₄ or LiNiPO _4, etc. It may be configured as. In addition, the nanopowder to the nanoparticles may be composed of Ni-YSZ or Pt-YSZ, etc., which are anode materials for fuel cells, or La _1-x Sr _x CoO ₃ (x = 0.1 to 0.9), La ₁ , which is a cathode material. It may be composed of _-x Sr _x MnO ₃ (x = 0.1 ~ 0.9), La _1-x Sr _x FeO ₃ (x = 0.1 ~ 0.9) or La _0.8 Sr _0.2 Fe _0.8 Co _0.2 O ₃ and the like. In the case of the electrode material for an electrochemical capacitor, RuO ₂ of the nano powder to an amorphous structure, the nanoparticles produced through the low temperature heat _{treatment, MnO 2, RuO 2 -MnO 2} , NiO, Co 2 O 3, NiO-Co 2 O ₃ or the like. In addition to the materials listed above, microrods and nanopowders according to the present invention can be prepared using various materials.

Hereinafter, the present invention will be described in detail with reference to examples, but these examples are only presented to more clearly understand the present invention, and are not intended to limit the scope of the present invention. It will be determined within the scope of the technical spirit of the claims.

Example 1 Tin Oxide (SnO) ₂ ) Preparation of Micro Rods and Nanoparticles

A tin oxide microrod was prepared using tin acetate as polyvinyl acetate, dimethylformamide (DMF), and tin oxide precursor.

First, a polymer solution in which 2.4 g of polyvinylacetate (molecular weight Mw: 1,300,000) was added to 15 ml of dimethylformamide and dissolved for about one day, and a solution in which 6 g of tin acetate was dissolved in 15 ml of dimethylformamide were mixed. 0.05 g of cetyltrimethyl ammonium bromide was added to the solution, followed by stirring for 2 hours.

The solution thus prepared was charged into a 20 ml syringe, and then slowly ejected (10 μl / min) to electrospin (humidity: 35%, available voltage: 13.7 kV, ambient temperature: 30 ° C.). Accordingly, a web (hereinafter, referred to as a 'composite fiber web') in which tin oxide precursor / polyvinylacetate (PVAc) composite fibers are entangled with each other by a sol-gel reaction while the solvent evaporates.

The composite fiber web was heat-treated at 450 ° C. for 30 minutes to remove the polymer, and a large amount of webs (hereinafter, referred to as “nano fiber webs”) in which tin oxide nanofibers were entangled with each other were produced. Figure 2 shows a scanning electron micrograph of the tin oxide nanofiber web obtained after the heat treatment. It can be seen that tin oxide nanofibers having a diameter of 200 to 600 nm are well formed.

The nanofiber web was then ultrasonically ground and ball milled (zirconia balls, 24 hours milled) to produce microrods. As shown in the scanning electron micrograph of FIG. 3, the tin oxide microrod has a width of 200 to 600 nm and a length of 500 nm to 10 μm. The microrods are composed of ultrafine nanoparticles, characteristically 5-20 nm in size.

In order to pulverize the micro rod, the grinding was performed for 10 hours using the micro bead milling (Super APEX Milling). After pulverization, the nanopowders were pulverized to a size of 5-20 nm, and as shown in the transmission electron micrograph of FIG. 4, SnO ₂ nanoparticles of 5-8 nm size of well-developed crystals were obtained.

Example 2 Preparation of Nickel Oxide (NiO) Micro Rod

Example 2 was subjected to the same process as in Example 1, except that nickel chloride was used as a nickel oxide precursor to prepare NiO instead of SnO ₂ .

First, a polymer solution in which 2.4 g of polyvinylacetate (molecular weight Mw: 1,300,000) was added to 15 ml of dimethylformamide and dissolved for about one day, and a solution in which 6 g of nickel chloride was dissolved in 15 ml of dimethylformamide were mixed. 0.05 g of cetyltrimethyl ammonium bromide was added to the solution, followed by stirring for 2 hours.

The solution thus prepared was charged into a 20 ml syringe, followed by slow ejection (10 μl / min) for electrospinning (humidity: 35%, available voltage: 13.2 kV, ambient temperature: 30 ° C.). Accordingly, a nickel oxide precursor / polyvinylacetate composite fiber web could be obtained by a sol-gel reaction while the solvent evaporated.

The composite fiber web was heat-treated at 450 ° C. for 30 minutes to remove the polymer and make a large amount of nickel oxide nanofiber web.

 5 shows a scanning electron micrograph of the nickel oxide nanofiber web obtained after the heat treatment. It can be seen that nickel oxide nanofibers having a diameter of 200 to 600 nm are well formed. Nickel oxide nanofibers can be observed by scanning electron microscopy composed of fine nanoparticles.

In order to produce a microrod composed of nanoparticles, the microfiber web was prepared by ultrasonic milling and ball milling (zirconia ball, 24 hours milling). As shown in the scanning electron micrograph of FIG. 6, the nickel oxide (NiO) microrods obtained after the first grinding have a width of 200 to 600 nm and a length of 500 nm to 10 μm. The microrods are composed of ultrafine nanoparticles of 5-20 nm in size.

In order to pulverize the micro rod, the grinding was performed for 10 hours using the micro bead milling (Super APEX Milling). After pulverization, a nanopowder pulverized to a size of 5 to 20 nm was obtained, which can be confirmed from the scanning electron micrograph of FIG. 7.

Example 3 Ruthenium oxide (RuO ₂ ) Preparation of Micro Rods and Nanoparticles

RuO ₂ microrods were prepared using polyvinyl acetate, dimethylformamide (DMF), and ruthenium chloride (RuCl ₃ ? X H ₂ O, Ruthenium (III) chloride hydrate (Aldrich)). Prepared.

First, 5 g of ruthenium chloride was dissolved and mixed in a polymer solution in which 1.6 g of polyvinylacetate (molecular weight Mw: 1,000,000) was added to 20 ml of dimethylformamide and dissolved for about one day.

The solution thus prepared was charged into a 20 ml syringe, and then slowly ejected (10 μl / min) to electrospin (humidity: 37%, available voltage: 14 kV, ambient temperature: 30 ° C.). As a result, a ruthenium oxide / polyvinylacetate composite fiber web could be obtained by a sol-gel reaction while the solvent evaporated.

The composite fiber web was heat-treated at 450 ° C. for 30 minutes to remove the polymer and produce a large amount of ruthenium oxide nanofiber web. 8 shows a scanning electron micrograph of the RuO ₂ nanofibers obtained after the heat treatment. It can be seen that ruthenium oxide nanofibers having a diameter of 100 to 500 nm are well formed.

The nanofiber web was subjected to ultrasonic milling and ball milling (zirconia balls, 24 hours milling) to prepare microrods. The microrods are composed of ultrafine nanoparticles of 5 to 15 nm in size.

In order to pulverize the microrods, grinding was performed for 10 hours using the micro bead milling (Super APEX Milling). After pulverization, the ruthenium oxide nanopowders pulverized to a size of 5 to 15 nm were obtained, and the size of RuO ₂ nanoparticles was confirmed in the transmission electron micrograph of FIG. 9.

Example 4 LiMnPO ₄  Manufacture of Micro Rods

LiMnPO ₄ microrods were prepared using polyvinylpyrrolidone (PVP), dimethylformamide (DMF), Lithium Acetylacetonate, Manganese (II) Chloride, and Triphenylphosphine.

First, 1.2 g of Lithium Acetylacetonate, Manganese (II) Chloride, and Triphenylphosphine were added to a polymer solution in which 3 g of polyvinylpyrrolidone (PVP, molecular weight Mw: 1,000,000) was dissolved in 15 ml of dimethylformamide for 1 day. , 3.184 g was added to mix the dissolved solution. After adding 0.002 g of CTAB (cetyltrimethyl ammonium bromide) to the solution, the mixture was further stirred for 2 hours.

The solution thus prepared was charged into a 20 ml syringe, and then slowly ejected (12 μl / min) to electrospin (humidity: 26%, available voltage: 14 kV, ambient temperature: 28.5 ° C.). Thereby, the LiMnPO ₄ precursor / polyvinylacetate composite fiber web can be obtained by sol-gel reaction while the solvent evaporates.

The composite fiber web was heat-treated at 600 ° C. under a reducing atmosphere of N ₂ (95%) / H ₂ (5%) gas for 2 hours to remove the polymer and prepare a large amount of LiMnPO ₄ nanofiber web. In addition, in order to improve the low electrical conductivity of Li, it is also possible to manufacture a nanofiber web by substituting a small amount of elements such as Nb, Al, Zr, Mg in place of Li. 10 shows a scanning electron micrograph of the LiMnPO ₄ nanofiber web obtained after the heat treatment. It can be seen that the LiMnPO ₄ nanofibers having a diameter of 200 to 800 nm are well formed.

The nanofiber web was subjected to ultrasonic milling and ball milling (zirconia balls, 24 hours milling) to prepare microrods. As shown in the scanning electron micrograph of FIG. 11, the LiMnPO ₄ microrods have a width of 20 to 500 nm and a length of 100 nm to 10 μm.

Example 5 La _0.8 Sr _0.2 MnO ₃  Preparation of Micro Rods and Nanoparticles

Lanthanum Chloride-7-hydrate (Crown Mw: 371.37), Strontium Chloride (Aldrich, Mw 158.53) and Manganese Chloride (Aldrich, Mw: 125.84) were weighed to a ratio of La: Sr: Mn of 0.8: 0.2: 1, After 7.5 g of water was mixed and stirred so that the total amount of the precursors was 3 g, 7.5 g of ethanol was added thereto. And 1 ml of acetic acid (Acetic Acid) was added as a catalyst, 0.5 g of CTAB was added to prepare an electrospinning solution.

The solution thus prepared was charged into a 20 ml syringe, and then slowly ejected (10 μl / min) to electrospin (humidity: 40%, available voltage: 11 kV, ambient temperature: 30 ° C.). Accordingly, La _0.8 Sr _0.2 MnO ₃ precursor / polyvinylpyrrolidone composite fiber web was obtained by sol-gel reaction while the solvent evaporated.

The composite fiber web was heat-treated at 400 to 900 ° C. for 1 hour to remove the polymer, and a large amount of La _0.8 Sr _0.2 MnO ₃ nanofiber web could be prepared. 12 shows a scanning electron micrograph of the La _0.8 Sr _0.2 MnO ₃ nanofiber web obtained after the heat treatment. It can be seen that La _0.8 Sr _0.2 MnO ₃ nanofibers having a diameter of 200 to 600 nm are well formed.

The nanofiber web was subjected to ultrasonic milling and ball milling (zirconia balls, 24 hours milling) to prepare microrods. As shown in the scanning electron micrograph of FIG. 13, the La _0.8 Sr _0.2 MnO ₃ microrod has a width of 50 to 600 nm and a length of 100 nm to 10 μm. The microrods are composed of ultrafine nanoparticles of 5-20 nm in size.

In order to pulverize the micro rod, the grinding was performed for 10 hours using the micro bead milling (Super APEX Milling). After pulverization, the nanopowders pulverized to a size of 5 to 20 nm were obtained, and the particle size was confirmed from the scanning electron micrograph of FIG. 14.

Example 6 Preparation of Pt Micro Rod and Nanoparticles

Polyvinylpyrrolidone (PVP), was prepared in dimethylformamide platinum (Pt) microrods and nanoparticles by using _{Chloroplatinic Acid Hexahydrate (H 2 PtCl 6} ? 6H 2 O) to (dimethylformamide, DMF), the platinum precursor.

First, 0.63 g of PVP (molecular weight Mw: 1,300,000) was mixed with DMF (0.283 g) + ethanol (0.86 g), and then 0.315 g of a platinum precursor was added. At this time, 0.86 g of DI Water was added and stirred. 0.05 g of cetyltrimethyl ammonium bromide was added to the solution, followed by stirring for 2 hours.

The solution thus prepared was charged into a 20 ml syringe, and then slowly ejected (10 μl / min) to electrospin (humidity: 35%, available voltage: 12 kV, ambient temperature: 30 ° C.). As a result, a platinum precursor / PVP composite fiber web could be obtained by a sol-gel reaction while the solvent evaporated.

The composite fiber web was heat-treated at 450 ° C. for 30 minutes to remove the polymer and produce a large amount of platinum nanofiber webs. Scanning electron micrographs of the platinum nanofiber web obtained after the heat treatment showed that the platinum nanofibers having a diameter of 200 to 600 nm were well formed.

The platinum nanofiber web was subjected to ultrasonic milling and ball milling (zirconia ball, 24 hours milling) to prepare microrods. Scanning electron micrographs of the Pt microrods of FIG. 15 may be used to observe the microrod shape composed of nanoparticles.

Pt nanorods were pulverized to 5-20 nm in size through a microbead milling process, and the particle size was confirmed on the scanning electron micrograph of FIG. 16.

Example 7 Preparation of Si Microrods and Nanoparticles

Silicon (Si) microrods and nanoparticles were prepared using polyvinylacetate (PVAc), dimethylformamide (DMF) and silicon acetate as silicon precursors (Silicon Acetate, Si (OOCCH ₃ ) ₄ , Alfa Aesar). .

First, 1.5 g of PVAc (molecular weight Mw: 1,300,000) was mixed with 15 ml of DMF, and then 3.96 g of a silicon precursor was added. At this time, 1 g of acetic acid was added and stirred for 2 hours.

The solution thus prepared was charged into a 20 ml syringe, and then slowly ejected (10 μl / min) to electrospin (humidity: 31%, available voltage: 13.4 kV, ambient temperature: 15 ° C.). As a result, a silicon precursor / PVAc composite fiber web could be obtained by a sol-gel reaction while the solvent evaporated.

In order to prevent the composite fiber web from being oxidized during heat treatment, the composite fiber web was heat treated at 450 ° C. for 30 minutes in a vacuum atmosphere to remove polymers, and a large amount of silicon nanofiber webs could be manufactured. It is also possible to heat-treat in a reducing atmosphere such as carbon monoxide (CO), a mixed gas of H ₂ / N ₂ . Scanning electron micrographs of the silicon nanofiber web obtained after the heat treatment showed that the silicon nanofibers having a diameter of 200 to 600 nm were well formed (see FIG. 17).

The silicon nanofiber web was ultrasonically crushed and ball milled (zirconia ball, 24-hour milling) to prepare microrods. Scanning electron micrographs of the Si microrods of FIG. 18 may be used to observe a microrod shape composed of nanoparticles. It can be seen that the microrods composed of silicon nanoparticles having a size of 5-20 nm are well formed.

As can be seen in the above embodiments, the manufacture of microrods and nanoparticles composed of fine nanoparticles is not limited to specific materials.

In the above, the present invention has been described with reference to the illustrated examples, which are merely examples, and the present invention may be embodied in various modifications and other embodiments that are obvious to those skilled in the art. Understand that you can.

1 is a view schematically showing a manufacturing process of the microrods and nanoparticles according to the present invention.

2 is a scanning electron micrograph of a SnO ₂ nanofiber web prepared according to Example 1 of the present invention.

Figure 3 is a scanning electron micrograph of the SnO ₂ micro rod ball milling after ultrasonic grinding according to Example 1 of the present invention.

4 is a scanning electron micrograph of the microbead milling SnO ₂ nanoparticles according to Example 1 of the present invention.

5 is a scanning electron micrograph of a NiO nanofiber web prepared according to Example 2 of the present invention.

FIG. 6 is a scanning electron micrograph of a NiO microrod subjected to ball milling after ultrasonic grinding according to Example 2 of the present invention. FIG.

7 is a scanning electron micrograph of the microbead milling NiO nanoparticles according to Example 2 of the present invention.

8 is a scanning electron micrograph of the RuO ₂ nanofiber web prepared according to Example 3 of the present invention.

9 is a transmission electron microscope photograph of RuO ₂ nanoparticles subjected to ball milling and microbead milling after ultrasonic grinding according to Example 3 of the present invention.

10 is a scanning electron micrograph of the LiMnPO ₄ nanofiber web prepared according to Example 4 of the present invention.

FIG. 11 is a scanning electron micrograph of a LiMnPO ₄ microrod subjected to ball milling after ultrasonic grinding according to Example 4 of the present invention.

12 is a scanning electron micrograph of La _0.8 Sr _0.2 MnO ₃ nanofiber web prepared according to Example 5 of the present invention.

FIG. 13 is a scanning electron microscope photograph of La _0.8 Sr _0.2 MnO ₃ microrods subjected to ball milling after ultrasonic grinding according to Example 5 of the present invention. FIG.

14 is a scanning electron micrograph of La _0.8 Sr _0.2 MnO ₃ nanoparticles microbead milling according to Example 5 of the present invention.

15 is a scanning electron micrograph of a Pt microrod subjected to ball milling after ultrasonic grinding according to Example 6 of the present invention.

16 is a scanning electron micrograph of Pt nanoparticles microbead milled according to Example 6 of the present invention.

17 is a scanning electron micrograph of Si nanofibers prepared according to Example 7 of the present invention.

FIG. 18 is a scanning electron micrograph of a Si microrod subjected to ball milling after ultrasonic grinding according to Example 7 of the present invention.

Claims (21)

It comprises at least one nanoparticles of the metal nanoparticles and metal oxide nanoparticles having an average size of 5 ~ 100nm, 50 to 1000nm in width and length-to-length ratio is 1.5 to 200 It is characterized by the following Pores having an average size of 1 to 50 nm are formed between the metal nanoparticles, the metal oxide nanoparticles, or between the metal nanoparticles and the metal oxide nanoparticles. The metal oxide nanoparticles include two or more metal oxides, and have at least one microstructure selected from solid solutions, mixed phases, and compounds of two or more metal oxides, and the metal nanoparticles and the metal oxide nanoparticles. The microrods of which particles have a crystalline structure, an amorphous structure, or a structure in which crystalline and amorphous are mixed. The method of claim 1, wherein the microrods, the microrods characterized in that the nanofibers having a diameter of 50 ~ 1000 nm made of at least one of the nanoparticles of the metal nanoparticles and metal oxide nanoparticles are short cut off. . delete The method of claim 1, wherein the metal nanoparticles are Pt, Au, Ag, Li, Si, Mn, Fe, Mg, Ca, Sn, Ti, Ni, Co, Cu, Zn, In, Mo, W, Ir and Ru Microrods, characterized in that the nanoparticles made of any one metal or two or more alloys selected from the group consisting of. The method of claim 1, wherein the metal oxide nanoparticles, (1) SnO ₂ , TiO ₂ , Fe ₂ O ₃ , Fe ₃ O ₄ , CoO, Co ₃ O ₄ , CaO, MgO, CuO, ZnO, In ₂ O ₃ , NiO, MoO ₃ , MnO ₂ , WO ₃ , Nanoparticles consisting of any one metal oxide or two or more composite metal oxides selected from the group consisting of RuO ₂ , IrO ₂ and V ₂ O ₅ , or (2) Zn ₂ SnO ₄ , CoSnO ₃ , Ca ₂ SnO ₄ , CaSnO ₃ , ZnCo ₂ O ₄ , Co ₂ SnO ₄ , Mg ₂ SnO ₄ , Mn ₂ SnO ₄ , CuV ₂ O ₆ , NaMnO ₂ and NaFeO ₂ Nanoparticles consisting of any one compound selected from the group consisting of, or (3) Li ₄ Ti ₅ O ₁₂ , LiCoO ₂ , LiNiO ₂ , LiNi _1-y Co _y O ₂ (y = 0.1 ~ 0.9), LiMn ₂ O ₄ , Li [Ni _1/2 Mn _1/2 ] O ₂ And nanoparticles consisting of any one of Li-containing transition metal oxides selected from the group consisting of LiFePO ₄ , or (4) LiFePO ₄ , LiMnPO ₄ , LiNiPO ₄ , LiCoPO doped with at least one of Mg ²⁺ , Al ³⁺ , Ti ⁴⁺ , Zr ⁴⁺ , Nb ⁵⁺ and W ⁶⁺ at a Li site of 1 at% or less; ₄ , LiAl _0.05 Co _0.85 Ni _0.15 O ₂ , Li [Ni _1/3 Co _1/3 Mn _1/3 ] O ₂ , Li [Ni _1/2 Mn _1/2 ] O ₂ , LiNi _1-x Co _x O Nanoparticles consisting of any one of Li-containing composite metal oxides selected from the group consisting of ₂ and LiNi _1-x Ti _{x / 2} Mg _{x / 2} O ₂ , or (5) nanoparticles consisting of composite metal oxides, which are complexes of metals and metal oxides of Pt-RuO ₂ , Ni-Y _0.08 Zr _0.92 O ₂ or Pt-Y _0.08 Zr _0.92 O ₂ , or (6) Y _0.08 Zr _0.92 O ₂ , La _1-x Sr _x CoO ₃ (x = 0.1 ~ 0.9), La _0.8 Sr _0.2 Fe _0.8 Co _0.2 O ₃ , La _1-x Sr _x MnO ₃ (x = 0.1 ~ 0.9), La _1-x Sr _x FeO ₃ (x = 0.1 ~ 0.9) and La _0.8 Sr _0.2 Fe _0.8 Co _0.2 O ₃ characterized in that the nanoparticles consisting of any one composite metal oxide selected from the group consisting of road. delete delete A material containing the microrods according to claim 1. The material of claim 8, wherein the material is an electrode active material for a secondary battery, an electrode material for an electrochemical capacitor, an electrode material for a fuel cell, a sensing material for a gas sensor, or a catalyst. Preparing a spinning solution in which at least one of a metal precursor and a metal oxide precursor are mixed with a polymer; Spinning the spinning solution onto a fiber under an electric field to form a composite fiber in which at least one of the metal precursor and the metal oxide precursor and the polymer are mixed; Heat treating the composite fiber to obtain nanofibers including at least one nanoparticles of metal nanoparticles and metal oxide nanoparticles from which the polymer is melt-removed from the composite fiber; Pulverizing the nanofibers to obtain a microrod including at least one nanoparticle among the metal nanoparticles and the metal oxide nanoparticles, The microrods include at least one nanoparticles of metal nanoparticles and metal oxide nanoparticles having an average size of 5 to 100 nm, and have a short length of 50 to 1000 nm and a ratio of length to width. The ratio is 1.5 or more and 200 or less, A method of manufacturing a microrod in which pores having an average size of 1 to 50 nm are formed between the metal nanoparticles, the metal oxide nanoparticles, or between the metal nanoparticles and the metal oxide nanoparticles. The method of claim 10, wherein the metal precursor is Ir, Ru, Pt, Au, Ag, Li, Si, Mn, Fe, Mg, Ca, Sn, Ti, Ni, Co, Cu, Zn, In, Mo or W ions At least one selected from the group consisting of a precursor containing, and a method for producing a micro-rod, characterized in that the metal can be formed through a heat treatment in a reducing atmosphere. The method of claim 10, wherein the metal oxide precursor is Li, Si, Mn, Fe, Mg, Ca, Sn, Ti, Ni, Co, Cu, Zn, In, Mo, V, W, P, Ir, Ru, Na At least one selected from the group consisting of precursors containing Al, Zr, Pt, Nb, Y, La or Sr ions, characterized in that the metal oxide can be formed through heat treatment in the air or in an oxidizing atmosphere Method of making microrods. The method of claim 10, wherein the polymer is polyvinylacetate, polyurethane, polyurethane copolymer, polyetherurethane, cellulose derivative, polymethylmethacrylate (PMMA), polymethylacrylate (PMA), polyacryl copolymer, Polyvinylacetate copolymer, polyvinyl alcohol (PVA), polyperfuryl alcohol (PPFA), polystyrene (PS), polystyrene copolymer, polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene oxide copolymer, polypropylene Oxide copolymer, polycarbonate (PC), polyvinyl chloride (PVC), polycaprolactone, polyvinylpyrrolidone (PVP), polyvinyl fluoride, polyvinylidene fluoride copolymer, polyacrylonitrile, Preparation of microrods, characterized in that at least one selected from the group consisting of polyamide, pitch and phenol resin Way. The method of claim 10, wherein the radiation is any one selected from among electro-spinning, melt-blown, flash spinning, and electrostatic melt-blown methods. It is spinning by the manufacturing method of the microrod. The method of claim 10, wherein the heat treatment is performed in air, an oxidizing atmosphere, a reducing atmosphere, or a vacuum at a temperature of 300 ° C. to 900 ° C. 12. The method of claim 10, wherein the nanofibers have a diameter of 50 to 1000 nm. The method of claim 10, wherein the grinding is performed by ultrasonic milling, followed by ball milling or attrition milling. delete Preparing a spinning solution in which at least one of a metal precursor and a metal oxide precursor are mixed with a polymer; Spinning the spinning solution onto a fiber under an electric field to form a composite fiber in which at least one of the metal precursor and the metal oxide precursor and the polymer are mixed; Heat treating the composite fiber to obtain nanofibers including at least one nanoparticles of metal nanoparticles and metal oxide nanoparticles from which the polymer is melt-removed from the composite fiber; Firstly crushing the nanofiber to obtain a microrod including at least one nanoparticle of the metal nanoparticles and the metal oxide nanoparticles; And pulverizing the microrods second to obtain nanopowders including at least one metal nanoparticles of the metal nanoparticles or at least one metal oxide nanoparticles of the metal oxide nanoparticles. The microrods include at least one nanoparticles of metal nanoparticles and metal oxide nanoparticles having an average size of 5 to 100 nm, and have a short length of 50 to 1000 nm and a ratio of length to width. The ratio is 1.5 or more and 200 or less, The method of claim 1, wherein pores having an average size of 1 to 50 nm are formed between the metal nanoparticles, the metal oxide nanoparticles, or the metal nanoparticle and the metal oxide nanoparticles. 20. The method of claim 19, wherein the first grinding is performed by ball milling or attrition milling after ultrasonic grinding, and the second grinding is performed by microbid milling. Method for producing a nanopowder characterized in that. 20. The method of claim 19, wherein the nanopowder has a size of 5 to 200 nm.

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