KR20190011362A - Spider network structure composition of N-doped carbon nanofibers containing MnCoOx nanoparticles, the preparation method, and application to anode material for secondary battery - Google Patents

Abstract

The present invention relates to a network structure composition of a web network structure and a manufacturing method thereof. The network structure composition of a web network structure comprises: nitrogen-doped carbon nanofibers having mesopores; and MnCoO_X nanoparticles arranged on the nitrogen-doped carbon nanofibers, wherein the nitrogen-doped carbon nanofibers are arranged to have a plurality of intersection points. Also, the present invention relates to a negative electrode composition for a secondary battery, a secondary battery including the same, and a manufacturing method of the negative electrode composition for a secondary battery. According to an embodiment of the present invention, the negative electrode composition for a secondary battery comprises: nitrogen-doped carbon nanofibers having mesopores; and MnCoO_X nanoparticles arranged in the nitrogen-doped carbon nanofibers, wherein the nitrogen-doped carbon nanofibers are arranged to have a plurality of intersection points, are capable of forming an electrode without a binder, and have excellent flexibility, thereby being used as an excellent secondary battery negative electrode material exhibiting stable charge capacity according to excellent charge capacity, long-term stability and current density, and as an excellent electrode material of a super capacitor, a sensor and the like.

Description

TECHNICAL FIELD [0001] The present invention relates to a sponge net structure composition of a nitrogen-loaded carbon nanotube including manganese-cobalt metal oxide nanoparticles, a method for synthesizing the same, and a negative electrode composition for a secondary battery comprising the preparation method of a nanocomposite to anode material for secondary battery}

The present invention relates to a sponge net structure composition of nitrogen-supported carbon nanotubes comprising manganese-cobalt metal oxide nanoparticles, a method of synthesizing the same, and a secondary battery anode composition, which comprises a secondary battery anode composition, And a method for producing the composition.

Recently, the demand of electronic devices has been rapidly increasing with the development of the information communication industry. There is a growing demand for higher energy density of batteries used as power sources for such electronic devices. Lithium secondary batteries are the ones that can best meet this demand, and researches thereon are actively being carried out.

Various types of carbon-based materials including artificial graphite, natural graphite, and hard carbon capable of lithium intercalation / deintercalation have been applied to the anode active material of the lithium secondary battery. The carbon-based graphite provides advantages in terms of energy density of a lithium battery and is most widely used because it guarantees a long life of a lithium secondary battery with excellent reversibility.

However, graphite has a problem in that its capacity is low in terms of energy density per unit volume of electrodes, and a high side discharge voltage tends to cause a side reaction with the organic electrolytic solution to be used, and there is a risk of ignition or explosion due to malfunction or overcharge of the battery.

In order to solve the above problems, a lithium secondary battery negative electrode composition using a transition metal oxide (TMO) has recently been reported. However, when such a secondary battery anode composition is used to form a lithium secondary battery, the electrical conductivity of the metal oxide is low, so that the electrical resistance increases and the capacitance decreases sharply.

Guoyong Huang et al., Core-Shell Ellipsoidal MnCo2O4 Anode with Micro- / Nano-Structure and Concentration Gradient for Lithium-Ion Batteries, ACS Appl. Mater. Interfaces 2014, 6, 21325

The invention relates to a flexible network structure having improved characteristics of Li ⁺ ion in a secondary cell, mitigating volume change, providing an efficient electron transfer path, high charge / discharge capacity, high stability, binder usage, A secondary battery including the negative electrode composition, and a method of manufacturing the same.

Compositions having a flexible network structure shape according to an embodiment of the present invention include: nitrogen-doped carbon nanofibers having mesopores; And MnCoO _x nanoparticles disposed on the nitrogen-doped carbon nanofibers, wherein the nitrogen-doped carbon nanofibers are arranged to have a plurality of intersection points to have a network structure shape.

A secondary battery according to an embodiment of the present invention includes: a negative electrode; anode; And an electrolyte disposed between the cathode and the anode, wherein the cathode comprises a nitrogen-doped carbon nanofiber having mesopores and a MnCoO _x nanoparticle disposed on the nitrogen-doped carbon nanofiber, wherein the nitrogen-doped carbon The nanofibers are arranged to have a plurality of intersection points to have a network structure shape.

A method of preparing a composition having a flexible network structure according to an embodiment of the present invention includes: forming a mixture by mixing a metal precursor, a polymer material, and a solvent; Forming a fiber composite using the mixed solution; And firing the fiber composite to form a nitrogen-doped carbon nanofiber network structure, and forming mesopores in the nitrogen-doped carbon nanofibers.

The step of forming the fiber composite may be carried out by electrospinning the mixed solution.

In the step of firing the fiber composite, the fiber composite may be firstly fired at 150 to 350 ° C, and the first fired fiber composite may be fired at 500 to 900 ° C in an N ₂ atmosphere.

A secondary battery negative electrode composition according to an embodiment of the present invention includes: nitrogen-doped carbon nanofibers having mesopores; And MnCoO _x nanoparticles disposed on the nitrogen-doped carbon nanofibers, wherein the nitrogen-doped carbon nanofibers are arranged to have a plurality of intersection points to form a network structure. Thereby, a binder is not required in the electrode construction, and a flexible electrode material composition is possible.

The composition having a flexible network structure according to an embodiment of the present invention, a secondary battery anode composition, a secondary battery including the same, and a manufacturing method thereof can improve the movement of Li + ions in the secondary battery and alleviate the volume change .

In addition, it can provide an efficient electron transfer path, has a high charge / discharge capacity, and has high stability.

Further, by providing the binder-free secondary battery negative electrode composition, it can be applied to a flexible secondary battery, a manufacturing method is simple, mass production is possible, and it is economical.

Figure 1 shows a composition according to an embodiment of the present invention.
FIG. 2 is a view showing the path of movement of ions and electrons in a secondary battery negative electrode composition according to an embodiment of the present invention.
3 illustrates a secondary battery according to an embodiment of the present invention.
Figure 4 illustrates a method of making a composition having a flexible network structure shape according to an embodiment of the present invention.
5 is a SEM image of the composition.
6 is a TEM image of the composition.
7 is an EDX analysis image of the composition.
Figure 8 shows the relationship between pore size distri- bution of mesopores according to mesopore size.
Figure 9 shows the CV curve of the composition.
Figure 10 shows a voltage-capacity graph.
FIG. 11 shows the capacity according to the number of charging and discharging cycles.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Further, the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. Accordingly, the shapes and sizes of the elements in the drawings may be exaggerated for clarity of description, and the elements denoted by the same reference numerals in the drawings are the same elements. In the drawings, like reference numerals are used throughout the drawings. In addition, "including" an element throughout the specification does not exclude other elements unless specifically stated to the contrary.

Flexible network structure Shaped  Composition and secondary battery anode composition

Figure 1 shows a composition according to an embodiment of the present invention.

Referring to FIG. 1, a composition having a flexible network structure according to an embodiment of the present invention includes: a nitrogen-doped carbon nanofiber having mesopores; And MnCoO _x nanoparticles disposed in the nitrogen-doped carbon nanofibers, wherein the nitrogen-doped carbon nanofibers are arranged to have a plurality of intersection points to form a unique network network structure.

Since the composition having the flexible network structure shape according to the embodiment of the present invention has unique structural characteristics, it can be utilized in various fields such as a secondary cell, a supercapacitor and a sensor. When a composition having a flexible network structure shape according to an embodiment of the present invention is used in a secondary battery, it can be applied to a negative electrode composition. This will be described below.

Compositions having a flexible network structure shape according to embodiments of the present invention can be used for secondary battery cathodes. At this time, the secondary battery negative electrode composition includes nitrogen-doped carbon nanofibers having mesopores; And MnCoOX nanoparticles disposed on the nitrogen-doped carbon nanofibers, wherein the nitrogen-doped carbon nanofibers are arranged to have a plurality of intersection points to have a network structure shape.

FIG. 2 shows the behavior of electrons and lithium ions when a secondary battery anode composition according to an embodiment of the present invention is applied to a lithium ion secondary battery. In FIG. 2, the electrons move along the nitrogen-doped carbon nanofibers, and the lithium ions move to the nitrogen-doped carbon nanofibers to cause charging and discharging. At this time, the lithium ions may react with the _X MnCoO nanoparticles to form LiMnCoO _X or Li ₂ MnCoO _X. The charge and discharge efficiency of the lithium ion is increased by the mesopores of the nitrogen-doped carbon nanofibers and the MnCoO _x nanoparticles arranged on the nanofibers. In addition, the nanofibers can buffer the volume change of the anode active material layer, which may occur when the MnCoO _x nanoparticles disposed on the nanofibers are charged and discharged with lithium ions.

In addition, the composition having the flexible network structure shape according to the embodiment of the present invention has a network structure in which the nitrogen-doped carbon nanofibers have a plurality of intersection points, so that a binder is not required in the construction of the electrode and flexibility is imparted to the electrode . The nitrogen-doped carbon nanofibers function as electron transfer paths, and even if deformed by external pressure, sufficient channels can be maintained for the cations to move. Therefore, the secondary battery anode composition according to the embodiment of the present invention can be applied to a flexible secondary battery.

As described above, the composition having the flexible network structure shape according to the embodiment of the present invention includes the nitrogen-doped carbon nanofibers and the MnCoO _X nanoparticles having the mesopores and forming the network structure, thereby improving the charging and discharging efficiency, And a problem caused by a volume change at the time of discharge can be prevented, and flexibility can be imparted to the secondary battery.

In a composition having a flexible network structure shape according to an embodiment of the present invention, in the MnCoO _x nanoparticles, MnCoO _x may have the formula MnCoO ₂ , MnCoO ₄ or MnCoO ₆ . The diameter of the MnCoO _x nanoparticles may be 5 to 50 nm, and preferably 10 to 30 nm in view of charging and discharging efficiency. If the diameter of the MnCoO _x nanoparticles is smaller than 5 nm, the charging and discharging efficiency may be decreased. If the diameter is larger than 50 nm, the structural stability of the carbon nanofibers may be deteriorated, and the capacity may be decreased.

In the nitrogen-doped carbon nanofibers, a plurality of fibers form a web roll. The diameter of the nitrogen-doped carbon nanofibers may be 100 to 1,200 nm, and preferably 400 to 800 nm in view of charging and discharging efficiency. When the diameter of the nitrogen-doped carbon nanofibers is less than 100 nm, it is difficult to form mesopores and MnCoO _x nanoparticles may be difficult to be produced. When the diameter of the nitrogen-doped carbon nanofibers is larger than 1200 nm, the electron transfer may not be smooth and the migration efficiency of lithium ions may be lowered.

Secondary battery

3 illustrates a secondary battery according to an embodiment of the present invention.

Referring to FIG. 3, a secondary battery according to an embodiment of the present invention includes a cathode; anode; And

Doped carbon nanofibers having mesopores and MnCoO _x nanoparticles disposed on the nitrogen-doped carbon nanofibers, wherein the nitrogen-doped carbon nano-particles have a mesopores, The fibers are arranged to have a plurality of intersection points to have a network structure shape.

The secondary battery according to the embodiment of the present invention may be a lithium ion secondary battery, but is not particularly limited. In addition, the composition of the present invention can be applied to a super capacitor, a sensor, etc. in addition to a secondary battery.

The cathode and the anode may be disposed to face each other, and a separator (not shown) may be disposed between the cathode and the anode. The cathode and the anode may include terminals for connection to the outside.

The negative electrode may include a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector. At this time, the anode active material layer includes nitrogen-doped carbon nanofibers having mesopores and MnCoO _x nanoparticles disposed on the nitrogen-doped carbon nanofibers, and the nitrogen-doped carbon nanofibers are arranged to have a plurality of intersection points, And a secondary battery negative electrode composition having a structure shape.

As described above, the secondary battery negative electrode composition is a secondary battery negative electrode composition according to an embodiment of the present invention, wherein the nitrogen-doped carbon nanofibers have a network shape having mesopores and a plurality of intersection points, The inclusion of MnCoO _x nanoparticles increases the mobility of electrons and lithium ions, thereby increasing the charging and discharging efficiency, preventing the problem of volume change during charging and discharging, increasing charging and discharging efficiency, A secondary battery can be provided.

In the MnCoO _x nanoparticles, MnCoO _x may have the formula MnCoO ₂ , MnCoO ₄ or MnCoO ₆ . The diameter of the MnCoO _x nanoparticles may be 5 to 50 nm, and preferably 10 to 30 nm in view of charging and discharging efficiency.

In the nitrogen-doped carbon nanofibers, a plurality of fibers form a web roll. The diameter of the nitrogen-doped carbon nanofibers may be 100 to 1,200 nm, and preferably 400 to 800 nm in view of charging and discharging efficiency.

The negative electrode current collector may be aluminum or stainless steel foil, but the present invention is not limited thereto.

The anode may include a cathode current collector and a cathode active material layer disposed on the cathode current collector.

The cathode active material layer may include a material capable of intercalating and deintercalating ions to be charged and discharged. Further, it may further include a conductive material and a binder. The conductive material imparts conductivity, and the binder serves to induce a good bond between the active materials and to allow the active material to adhere well to the current collector.

The anode current collector may be aluminum or stainless steel foil, but the present invention is not limited thereto.

The electrolyte may be a non-aqueous electrolyte (organic electrolyte) or an aqueous electrolyte generally used in a secondary battery. Further, it may include lithium ions.

The organic electrolyte may include an organic solvent. The organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move. The organic solvent may be selected from carbonate, ester, ether, ketone, alcohol and aprotic solvents. The organic electrolytes may be used in a mixture of one or more, and the mixing ratio in the case of using one or more of the organic electrolytes may be appropriately adjusted according to the performance of the desired cell, and the present invention is not limited thereto.

The aqueous electrolyte includes an aqueous solution of sodium sulfate (Na ₂ SO ₄ ), sodium nitrate (NaNO ₃ ), sodium chloride (NaCl), sodium carbonate (Na ₂ CO ₃ ), sodium hydrogen carbonate (NaHCO ₃ ) or sodium hydroxide .

Flexible network structure Shaped  Method for producing a composition

Figure 4 illustrates a method of making a composition having a flexible network structure shape according to an embodiment of the present invention.

Referring to FIG. 4, a method of fabricating a flexible network structure according to an embodiment of the present invention includes: forming a mixed solution by mixing a metal precursor, a polymer material, and a solvent; Forming a fiber composite using the mixed solution; And firing the fiber composite to form a nitrogen-doped carbon nanofiber network structure, and forming mesopores in the nitrogen-doped carbon nanofibers.

A metal precursor, a polymer material, and a solvent are mixed to form a mixed solution.

The metal precursor may include a manganese precursor and a cobalt precursor. Manganese precursor is manganese acetate dihydrate _{(Mn (A C2) .2H 2} O) , and Mn (NO _{3) 2,} MnCl ₂ can be any one of, the cobalt precursor to cobalt acetate tetrahydrate (Co _(C A) ₂ .4H ₂ O), Co (NO ₃ ) ₂ and CoCl ₂ .

Polymeric materials can form carbon skeletons in nitrogen-doped carbon nanofibers. The polymeric material for forming the carbon skeleton is selected from the group consisting of polyacrylonitrile (PAN), polyaniline (PANI), urea thiophene, pyrrole, styrene, ethylene dioxythiophene, phenylene, Carbazolyl, < / RTI >

The solvent may include an N source for doping nitrogen to the nitrogen doped carbon nanofibers. The solvent may include dimethylformamide (DMF) to provide an N source.

The metal precursor may be added to the solvent in an amount of 1 to 5 moles each. When the content of the metal precursor is out of the above range, it is difficult to form a fiber composite.

The step of forming the fiber composite using the mixed solution will be described.

This step can be carried out by electrospinning the mixed solution. The electrospinning may be performed by connecting a mixed liquid to an electrospinning nozzle of an electrospinning device using a feeding device, forming a high electric field (high electric field, 10 kV to 100 kV) between the nozzle and the current collector by using a high voltage generating device, Or by radiating through a nozzle. The size of the electric field is related to the distance between the nozzle and the current collector, and the relationship between them can be used in combination to facilitate electrospinning. As the electrospinning device to be used at this time, those generally used can be used, and electroblast method, centrifugal electrospinning method and the like can be used.

The fiber composite may include manganese (Mn), cobalt (Co), and polyacrylonitrile (PAN). Further, the fiber composite may have a network structure having a plurality of intersection points.

The step of firing the fiber composite will be described.

The nitrogen-doped carbon nanofibers having mesopores can be formed by high-temperature firing the fiber composite in the preceding step.

The firing can be performed under conditions sufficient for the carbon structure to be well formed in the polymer material of the fiber composite and to be doped with nitrogen. In addition, the firing can be performed at different temperatures at various stages. For example, the fiber composite can be firstly fired at a relatively low temperature and the first fired fiber composite can be secondarily fired at a relatively high temperature in an N ₂ atmosphere. The first firing may be performed at 150 to 350 ° C for 30 to 180 minutes, and the second firing may be performed at 500 to 900 ° C for 30 to 180 minutes.

During the first firing, the acetate groups of manganese (Mn) and cobalt (Co) are converted to CO ₂ and the polyacrylonitrile (PAN) polymer material is decomposed to form a carbon fiber structure and form NH ₃ have. At this time, mesopores are formed in the carbon structure by the production of CO ₂ , NH _3, and other gases. During the secondary firing, the ring structure of the polymer substance is opened and converted into a carbon skeleton, and the MnCoO _x nanoparticles are uniformly relocated to the carbon skeleton.

The composition produced by the manufacturing method according to the embodiment of the present invention is a nitrogen doped carbon nanofiber having mesopores; And MnCoO _x nanoparticles disposed on the nitrogen-doped carbon nanofibers, wherein the nitrogen-doped carbon nanofibers are arranged to have a plurality of intersection points to have a network structure shape.

Example: Flexible network structure Shaped  Preparation of composition

Example 1

1 g of polyacrylonitrile (PAN) having a weight average molecular weight of 150,000 was added to 10 mL of dimethylformamide (DMF) and dissolved by stirring at 70 DEG C for 4 hours. Where 2 mol of manganese acetate dihydrate of the _{(Mn (A C) 2 .2H} 2 O) ( Sigma Aldrich seed, Sigma Aldrich) and cobalt acetate tetrahydrate (Co _(C A) ₂ .4H ₂ O) 4 moles ( Sigma Aldrich) were mixed and stirred at 70 ° C using a mechanical stirrer. The solution was stirred again for 4 hours to form a mixed solution.

Next, the mixed solution was electrospun to form a fiber composite in which Mo-Co-PAN was compounded. For this electrospinning, the mixed solution was placed in a plastic syringe with a 23 gauge needle and electrospun onto a drum current collector covered with aluminum foil. The distance between the collector and the needle was maintained at 18 cm and the rotation of the drum was maintained at 500 rpm. And supplied at an injection rate of 1 mL / h under a condition of 16 kV. 8 mL of a mixed solution was electrospun to form a Mo-Co-PAN complexed fiber composite.

Next, the fiber composite formed on the aluminum foil was peeled off from the aluminum foil and fired to produce a nitrogen-doped carbon nanofiber having mesopores and containing MnCoO _x nanoparticles. The fiber composite was sintered at 250 ° C for 1 hour and then at 700 ° C for 1 hour in an N ₂ atmosphere.

Comparative Example 1

The mixed solution was formed only of polyacrylonitrile (PAN) and dimethylformamide (DMF) without mixing the metal precursor. The remaining process was carried out in the same manner as in Example 1.

5 (b) and 5 (d) are SEM images of Example 1, and (a) and (c) are SEM images of Comparative Example 1. FIG. In FIG. 5, Example 1 shows that mesopores are formed on the surface of the carbon nanofibers, and nanoparticles are arranged on the nanofibers. On the other hand, in Comparative Example 1, no mesopores or nanoparticles were arranged on the surface of the carbon nanofibers. In FIG. 5, the diameter of the carbon nanofibers of Example 1 is about 700 nm, while the diameter of the carbon nanofibers of Comparative Example 1 is about 400 nm. This is because in Example 1, the carbon skeleton was formed thicker due to the formation of mesopores and nanoparticles.

6 (b) to 6 (d) are TEM images of Example 1, and FIG. 6 (a) is a TEM image of Comparative Example 1. In Figure 6, Example 1 shows nanoparticles of 10-20 nm in diameter. The EDX analysis image (FIG. 7) of Example 1 shows that the nanoparticles are MnCoO _X nanoparticles. FIG. 7 shows that Mn, Co, C, N and O are uniformly distributed.

Figure 8 shows the relationship between pore size distri- bution of mesopores according to mesopore size. According to FIG. 8, it can be expected that diffusion of ions in the secondary battery proceeds smoothly when the mesopores have diameters of 3 and 12 nm.

Figs. 9 to 11 show electrical characteristics of Example 1 and Comparative Example 1. Fig. Electrical characteristics were evaluated using a CR2032 coin type test cell. In the coin-type test cell, Li metal foil (purity: 99.9%, thickness: 150 μm) was used as a cathode and ethylene carbonate (EC) and dimethyl carbonate (DMC) 0.1 M of LiPF 6, and a cell guide 2400 (microporous polypropylene sheet) was used as a separation membrane. Example 1 and Comparative Example 1 were punched out into a circle having a diameter of 14 mm and used as an anode electrode without adding a conductor or a binder. Thereafter, it was dried in a vacuum oven to remove water, and the CR2032 coin type test cell was assembled. The CV curve was measured at a scan rate of 0.1 mV / s at 0.01 to 3.00 V.

9 shows the CV curve. (a) is the CV curve of the first embodiment, and (b) is the CV curve of the first comparative example.

Referring to FIG. 9 (a), it can be seen that the oxidation / reduction peak pair repeatedly appeared at 0.33 V / 1.29 V and 0.47 V / 2.05 V from the second cycle after Example 1 was used as the cathode. This means that a reversible reaction in which Li < + > is charged and discharged to the cathode stably occurs. Referring to FIG. 9 (b), when Comparative Example 1 was used as a negative electrode, no oxidation / reduction peak was observed after the second cycle, and it was confirmed that no reversible reaction occurred stably. It can be interpreted that a solid electrolyte interphase (SEI) is formed on the surface of the cathode after the first cycle, thereby interfering with the reversible reaction.

Figure 10 shows a voltage-capacity graph. (a) is a voltage-capacity graph of Example 1, and (b) is a voltage-capacity graph of Comparative Example 1. Fig. The charge / discharge characteristics of Example 1 and Comparative Example 1 were evaluated in a potential range of 0.01 to 3.00 V and a current density range of 100 mA / g.

10 (a), the discharge capacity and the charge capacity in the first cycle were 1103 and 610 mAh / g, respectively, when Example 1 was used as the cathode. From the second cycle, the discharge capacity and charge capacity were 608 and 597 mAh / g, respectively. 10 (b), when Comparative Example 1 is used as a negative electrode, the discharge capacity and the charge capacity in the second and subsequent cycles as well as the discharge capacity and the charge capacity in the first cycle are lower than those in Example 1 used as the cathode It looked.

FIG. 11 shows the capacity according to the number of charging and discharging cycles. The current density was increased step by step starting from the 10th cycle, and the capacity was measured at an initial current density of 100 mA / g after 80 cycles. When Example 1 was used as the negative electrode (MnCoO _x @ NCNF), the initial current density was further increased after the 80th cycle than the initial capacity. It can be understood that the nitrogen-doped carbon nanofibers serve as electron transfer paths, and mesopores and MnCoO _x nanoparticles improve the diffusion rate of Li ⁺ . When Comparative Example 1 is used as a negative electrode (NCNF), the capacity is small overall, and after 80 cycles, the capacity does not increase beyond the initial capacity.

The present invention is not limited to the above-described embodiment and the accompanying drawings, but is intended to be limited by the appended claims. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

100: composition with flexible network structure morphology
110: nitrogen-doped carbon nanofiber
120: MnCoO _X nanoparticles
1000: secondary battery
1100: cathode
1110: cathode collector
1120: anode active material layer
1200: anode
1210: positive collector
1220: cathode active material layer
1300: electrolyte

Claims (12)

Nitrogen-doped carbon nanofibers having mesopores; And
And MnCoO _X nanoparticles disposed on the nitrogen-doped carbon nanofibers,
Wherein the nitrogen-doped carbon nanofibers are arranged to have a plurality of intersection points to have a flexible network structure shape.
The method according to claim 1,
Wherein the MnCoO _x nanoparticles have a flexible network structure of 5 to 50 nm in diameter.
The method according to claim 1,
Wherein the nitrogen-doped carbon nanofibers have a diameter of 100 to 1200 nm.
cathode;
anode; And
And an electrolyte disposed between the cathode and the anode,
The negative electrode,
Doped carbon nanofibers having mesopores and MnCoO _x nanoparticles disposed on the nitrogen-doped carbon nanofibers, wherein the nitrogen-doped carbon nanofibers are arranged to have a plurality of intersections to form a network structure.
Mixing a metal precursor, a polymer material, and a solvent to form a mixed solution;
Forming a fiber composite using the mixed solution; And
And firing the fiber composite to form a nitrogen-doped carbon nanofiber network structure, and forming mesopores in the nitrogen-doped carbon nanofibers.
6. The method of claim 5,
Wherein the step of forming the fiber composite has a flexible network structure shape in which the mixed solution is electrospun.
6. The method of claim 5,
The step of firing the fiber composite includes:
The fiber composite is firstly fired at 150 to 350 占 폚,
The primary method of producing a composition having the fired fiber composite a flexible network structure shaped to secondary baking at 500 to 900 ℃ in N ₂ atmosphere.
6. The method of claim 5,
Wherein the metal precursor has a flexible network structure including a manganese precursor and a cobalt precursor.
6. The method of claim 5,
Wherein the polymeric material has a flexible network structure shape comprising polyacrylonitrile (PAN).
6. The method of claim 5,
Wherein the solvent has a flexible network structure shape comprising dimethylformamide (DMF).
6. The method of claim 5,
Wherein the fiber composite has a flexible network structure shape comprising manganese, cobalt and polyacrylonitrile (PAN).
Nitrogen-doped carbon nanofibers having mesopores; And
And MnCoO _X nanoparticles disposed on the nitrogen-doped carbon nanofibers,
Wherein the nitrogen-doped carbon nanofibers are arranged so as to have a plurality of intersection points to form a flexible network structure.

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