KR101696902B1 - Active material, method of preparing the active material, electrode including the active material, and secondary battery including the electrode - Google Patents

Abstract

1. An active material comprising vanadium oxide represented by the following formula (1), wherein vanadium of the vanadium oxide has a mixed oxidation state of a plurality of oxidation states, and the oxidation number has an oxidation state of +3, wherein the vanadium oxide has a oxidation state of +3. Electrode and a secondary battery comprising the same.
[Chemical Formula 1]
VO _x
1.5 < x < 2.5 in the general formula (1).

Description

TECHNICAL FIELD The present invention relates to an active material, an electrode including the same, and a secondary battery including the electrode.

An electrode including the active material, and a secondary battery including the electrode.

The secondary battery can be classified into a lithium secondary battery, a sodium secondary battery, and a calcium secondary battery depending on the kind of metal that conducts electric conduction. The secondary battery can be charged by performing charging and can be used repeatedly, which is excellent in convenience and has been used in a wide range of fields.

The secondary battery has a structure in which a conductor capable of reserving ions of a metal having a strong ionization tendency in the state of an ion is disposed as an anode and an electrolyte is interposed between the anode and the cathode.

In recent years, electronic devices such as portable telephones, video cameras, computers, and the like are becoming portable and miniaturized. In addition to these circumstances, the battery, which is a main power supply device for these devices, is also becoming smaller. In addition, as the functions of these devices are diversified, the power consumed is increasing. In order to meet these requirements, there is an increasing demand for high-capacity and long-life electrode active materials for secondary batteries.

One aspect is to provide an active material with improved capacity and lifetime characteristics and a method of manufacturing the same.

Another aspect is to provide an electrode containing an active material.

Another aspect of the present invention is to provide a secondary battery having improved cell performance by providing the electrode.

According to an aspect of the present invention, there is provided an active material comprising vanadium oxide represented by the following formula (1), vanadium of the vanadium oxide having a mixed oxidation state of a plurality of oxidation states, and an oxidation state of +3.

[Chemical Formula 1]

VO _x

1.5 < x < 2.5 in the general formula (1).

According to other aspects

Adding a reducing agent and a solvent to the starting material comprising vanadium to obtain a mixture; And applying an electromagnetic wave to the mixture to reduce the starting material to obtain a vanadium oxide represented by the following Formula 1,

There is provided a process for producing an active material, wherein the vanadium of the vanadium oxide has a mixed oxidation state of a plurality of oxidation water and an oxidation state of +3 is obtained.

[Chemical Formula 1]

VO _x

1.5 < x < 2.5 in the general formula (1).

According to another aspect, there is provided an electrode comprising the above-mentioned active material.

According to another aspect, there is provided a secondary battery including the above-described electrode.

According to another aspect, a magnesium secondary battery is provided.

According to another aspect, a sodium secondary battery is provided.

According to another aspect, a lithium secondary battery is provided.

According to one aspect, there is provided an active material having high capacity and long life characteristics by controlling the oxidation state and shape of vanadium in vanadium oxide. When an electrode using such an active material is employed, a secondary battery having improved lifetime and capacity can be manufactured.

FIG. 1 is a diagram for explaining the formation process of vanadium oxide having a mixed oxidation state of oxidation numbers +3, +4, and +5 according to one embodiment.
2 is a schematic view illustrating a structure of a secondary battery according to an embodiment.
FIG. 3 shows X-ray photoelectron spectroscopy (XPS) analysis results of vanadium oxides according to Examples 1-3 and Comparative Example 1. FIG.
4 shows the XPS analysis results of the magnesium secondary battery of Production Example 1 before and after charging / discharging.
Fig. 5 shows the impedance analysis results of the magnesium secondary batteries of Production Examples 1 and 3 and Comparative Production Example 1. Fig.
Fig. 6 is an enlarged view of a partial area of Fig.
7A, 8A, and 9A are electron micrographs of vanadium oxide of Example 1, Example 3, and Comparative Example 1, respectively.
Figs. 7B, 8B and 9B are enlarged electron micrographs of Figs. 7A, 8A and 9A, respectively.
FIGS. 10A and 11A are transmission electron microscopic photographs of vanadium oxides of Example 1 and Example 3, respectively.
Figs. 10B and 11B are enlarged views of partial regions of Figs. 10A and 11A, respectively.
12 shows X-ray diffraction analysis results of vanadium oxides of Example 1, Example 3 and Comparative Example 1. Fig.
FIG. 13 is a graph showing changes in voltage with respect to the capacity of the magnesium secondary batteries of Production Example 1, Production Example 2 and Comparative Production Example 1. FIG.
Fig. 14 shows the capacity retention ratios of the magnesium secondary batteries of Production Example 1, Production Example 3 and Comparative Production Example 1. Fig.
FIG. 15 is a graph showing changes in voltage with the capacity of the sodium secondary battery of Production Example 4 and Comparative Production Example 2; FIG.
16 shows the capacity retention rates in the sodium secondary batteries of Production Example 4 and Comparative Production Example 2. Fig.

Hereinafter, an active material according to one embodiment, a method of manufacturing the same, an electrode including the active material, and a secondary battery including the electrode will be described in more detail.

There is provided an active material comprising vanadium oxide represented by the following Chemical Formula 1, wherein vanadium of the vanadium oxide has a mixed state of a plurality of oxidized water, and the oxidation number includes an oxidation state of +3.

The vanadium has a mixed oxidation state of three oxidation numbers. Vanadium additionally contains an oxidation state with oxidation numbers of +4 and +5. The vanadium of the vanadium oxide includes, for example, an oxidation state of +3 oxidation, +4 oxidation and +5 oxidation.

[Chemical Formula 1]

VO _x

1.5 < x < 2.5 in the general formula (1).

The vanadium oxide is a nanostructure, and may have a nanotube or nano-sheet shape. The nanosheet is composed of one layer or a plurality of layers stacked.

The nanosheet may have a circular, oval, triangular, square, pentagonal or hexagonal shape. And the nanotubes may be multiwall nanotubes. Here, the wall thickness of the multi-wall is, for example, 30 to 50 nm, specifically about 40 nm.

In the above formula (1), x is 1.9? X <2.2, specifically 1.995 to 2.13.

FIG. 1 illustrates a process of forming an active material for a secondary battery according to one embodiment.

1, when vanadium pentoxide (V ₂ O ₅ ), one of the vanadium oxides, is reacted with amine (RNH ₂ ) according to the conventional heat treatment method (route B), vanadium pentoxide is oxidized to vanadium And a nitro compound (RNO ₂ ) to form a vanadium oxide containing vanadium having oxidation numbers of +4 and +5.

According to one embodiment, when a microwave hydrothermal reaction is performed in the presence of an amine compound, which is a reducing agent, vanadium pentoxide (V ₂ O ₅ ), vanadium in which oxidation number of +3 is vanadium, oxidation number +4 vanadium and oxidation number + Oxides can be obtained. Here, the shape of the finally obtained vanadium oxide, the inter-layer distance, and the like can be controlled by controlling the synthesis conditions including the content of the reducing agent and the microwave irradiation conditions.

The content of the reducing agent is in the range of 0.1 to 1.1 mol based on 1 mol of vanadium pentoxide.

For example, when the content of the reducing agent is 0.1 to 0.5 mole relative to 1 mole of the starting material containing vanadium (for example, vanadium pentoxide), vanadium oxide having a nanosheet shape can be obtained. When the content of the reducing agent is 0.6 to 1.1 moles with respect to 1 mole of vanadium pentoxide as the starting material, vanadium oxide having a nanotube shape having a wide interlayer distance can be obtained.

As described above, when microwave is applied in the reaction between vanadium pentoxide and an amine compound, energy transfer from a microwave to a reaction material through a solvent such as water is effective through resonance and relaxation The heat in the hydrothermal synthesis reactor is uniformly and rapidly supplied within a short time, and the pressure is elevated to generate a strong reducing atmosphere instantaneously. As such a strong reducing atmosphere is formed, it is possible to obtain vanadium oxide having a mixed oxidation state of +3, +4 and +5.

On the other hand, it is difficult to obtain a vanadium oxide having a mixed oxidation state of +3, +4 and +5 in the case of performing a reaction of applying a usual heat.

Hereinafter, a method of manufacturing an active material according to one embodiment will be described.

The starting material containing vanadium and the reducing agent are dissolved or dispersed in a solvent to obtain a mixture. Here, at least one solvent selected from water and alcohol is used. As the alcohol, methanol, ethanol, butanol, propanol and the like are used.

The vanadium-containing starting material is, for example, ivanonium pentoxide (V ₂ O ₅ ) or vanadium oxydiacetate {VO (Ac) ₂ }. In VO (Ac) ₂ , vanadium has an oxidation number of +4.

In the conventional active material manufacturing method, vanadium oxide gel is used as a starting material containing vanadium, but vanadium pentoxide powder is used as a starting material in one embodiment of the present invention.

The reducing agent serves as a template for obtaining vanadium oxide as a target while reducing vanadium pentoxide and functions as an interlayer securing member for widening the interlayer distance in the finally obtained vanadium oxide. As described above, when the interlayer distance of the vanadium oxide is increased, it becomes possible to secure the doping and de-doping in and out of ions such as lithium ion, magnesium, and sodium ions. Here, doping refers to a phenomenon in which ions such as lithium ions enter the electrode active material, which means both storing, supporting, adsorbing, or inserting. And de-doping refers to the phenomenon that lithium ions come out as opposed to doping.

The reducing agent may be any substance that can reduce vanadium pentoxide. For example, amine-based materials are used.

The reducing agent may be a common reducing agent together with the amine-based material described above. Common reducing agent materials include hydrogen compounds and cysteine compounds.

The amine-based material may be, for example, a primary amine compound, specifically an alkylamine having 4 to 18 carbon atoms.

Examples of the amine-based substance include octadecylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecyl Amines, heptadecyl amines, and hexadecyl amines.

The content of the reducing agent is 0.1 to 1.0 mol, for example, 0.5 to 1.0 mol, based on 1 mol of the starting material (for example, vanadium pentoxide (V ₂ O ₅ )) containing vanadium as a starting material.

The content of the reducing agent has a very important effect on the shape of the finally obtained vanadium oxide and the interlayer distance.

The content of the solvent is 100 to 3000 parts by weight based on 100 parts by weight of vanadium pentoxide oxide. When the content of the solvent is within the above range, a mixture in which vanadium pentoxide and the reducing agent are uniformly dissolved or dispersed can be obtained.

According to one embodiment, a mixture of water and an alcohol is used as the solvent. Wherein the volume ratio of water to ethanol is 1: 1 to 20: 1, for example 5: 1.

The starting material may be reduced by applying an electromagnetic wave to the mixture to obtain the vanadium oxide represented by the formula (1).

The electromagnetic waves may be micro-files.

The reduction of the starting material can be carried out by microwave hydrothermal reaction. According to an embodiment, a mixture containing vanadium-containing starting material, a reducing agent and a solvent obtained according to the above process is placed in a reactor equipped with a microwave irradiation device, and a microwave is applied to perform a microwave hydrothermal reaction.

After the hydrothermal reaction, the resulting product is washed, filtered and dried to obtain the desired vanadium oxide.

The microwave has an output of 200 to 1500 W, and a frequency of 1 to 2.45 GHz. When a microwave having such an output and a frequency is used, vanadium oxide having a desired mixed oxidation number can be obtained.

The output of the microwave is, for example, in the range of 400 to 1200 W, specifically 800 to 900 W. And the frequency of the microwave is 1 to 2.45 GHz, for example, 1.5 to 2.2 GHz. When a microwave having such an output and a frequency is irradiated, the reaction temperature in the reactor is in the range of 160 to 230 占 폚, for example, 180 to 200 占 폚.

The time for which the microwave is applied depends on the output and the frequency of the microwave.

It is different. The reaction time for applying microwaves is, for example, in the range of 12 to 24 hours, for example 18 to 21 hours. During this reaction time, the microwave hydrothermal synthesis reaction proceeds while repeatedly performing the microwave application and the resting step.

The pressure of the reactor during the hydrothermal reaction is, for example, in the range of 150 to 250 psi.

The reaction time after the microwave irradiation is maintained for 15 to 20 hours, for example, 18 to 20 hours. The reaction time using the microwave is shorter than the conventional heat treatment method.

When washing, use alcohol or water.

Drying is carried out, for example, at 80 to 100 ° C.

The vanadium oxide obtained according to the above process may be pulverized into a predetermined particle size by a ball mill or the like, and the vanadium oxide may be used as an electrode active material by classifying it by sieving.

According to one embodiment, the average oxidation number of the active material is from 3.8 to 4.3, for example from 3.99 to 4.26.

In the above formula (1), x is 1.995 to 2.13.

The vanadium oxide obtained by the above process may have a nanosheet or nanotube shape.

The nano-sheet comprises 1-10 layers, for example, 1 to 5 layers, specifically 1 to 3 layers, and the total thickness of the nano-sheet is 3 to 15 nm. And the interlayer distance is 2.5 to 3.5 nm, for example about 2.8 nm.

The nanotubes may be of the open type, for example. The vanadium oxide has nanotubes of wide open type and open at both ends, so that ions such as magnesium ion, sodium ion, and lithium ion are easily inserted and moved.

The length, outer diameter and inner diameter of the nanotube are not limited, but are, for example, 1 to 2 탆 in length, 15 to 50 nm in inner diameter, for example, 30 to 40 nm, and outer diameter of 50 to 100 nm, for example, 80 nm. And the interlayer distance is 2.5 to 3.8 nm, for example about 2.8 nm, and the length is 1 to 3 um. By using nanotubes having such outer diameters, inner diameters, and lengths, it is possible to obtain a secondary battery having excellent capacity and life characteristics.

Vanadium oxide having a nanotube shape is excellent in life characteristics because of a wide interlayer distance. And, vanadium oxide having nano sheet shape has excellent surface area and excellent capacity characteristics.

The mixing ratio of vanadium oxide of 3 in number, vanadium in oxidation number + 4 and vanadium in oxidation number +5 in vanadium oxide having mixed oxidation state can be measured by various methods.

For example, in the XPS analysis, the mixing ratio of vanadium in the oxidation state +3, vanadium in the oxidation state +4, and vanadium in the oxidation state +5 is calculated by calculating the integral value of the peak corresponding to the binding energy of the V 2p orbital, Lt; / RTI &gt;

The trivalent vanadium oxide is related to the peak corresponding to the binding energy 514.7 515.7 eV, and the vanadium oxide 4 vanadium corresponds to the peak corresponding to the binding energy 516.0 517.0 eV. And the vanadium oxide having a valence of 5 is associated with a peak corresponding to a binding energy of 517.3 ± 518.3 eV.

In the XPS analysis, the atomic ratio of vanadium having an oxidation number of +3 to vanadium having an oxidation number of +4 is 1: 1.33 to 1: 6. And the atomic ratio of the vanadium having the oxidation number of +3 to the vanadium having the oxidation number of +5 is 1: 0.83 to 1: 5. And the atomic ratio of vanadium having oxidation number of +4 to vanadium having oxidation number of +5 is 1: 0.42 to 1: 1.5

In the XPS analysis, the content of vanadium in terms of the oxidation number +3 and the total amount of vanadium in oxidation number + 4, vanadium in oxidation number +4 and vanadium in oxidation number +5 is 10 to 30 atomic%, for example, 13 to 29 atomic%. At this time, the content of vanadium in the oxidation state +4 is 40 to 60 atomic%, and the content of vanadium in the oxidation state + 5 is 25 to 50 atomic%.

In the XRD analysis, (001) and (002) peaks appear when the 2θ is 10 ° or less.

The X-ray diffraction analysis is carried out using a Rigaku RINT2200HF + diffractometer using Cu Kradiation (1.540598 Å). (001) peak appears in the region of about 3.2 ± 0.3 ° in 2θ and the (002) peak appears in the region of about 6.2 ± 0.3 ° in 2θ.

(002) peak / (001) peak intensity ratio is 0.6 or less, for example, 0.3 to 0.6, and the half-value width (FWHM) of the (001) peak is 0.5 or less, for example, 0.1 to 0.5.

After charging and discharging the secondary battery employing the vanadium oxide as an active material according to one embodiment, the mixture ratio of vanadium oxide having +3 oxidation number, vanadium having oxidation number + 4, and vanadium having oxidation number +5 differ in vanadium oxide.

According to another embodiment, after the secondary battery is charged and discharged, the active material contained in the electrode of the secondary battery includes vanadium oxide represented by the following formula (1). In the XPS analysis, vanadium The content is 10 to 25 atomic% based on the total amount of vanadium of oxidation number +3, vanadium of oxidation number +4, and vanadium of oxidation number +5.

[Chemical Formula 1]

VO _x

1.5 < x < 2.5 in the above formula (1), for example, 1.9? X < 2.2.

According to XPS analysis, the content of vanadium in the oxidation state +4 is 40 to 60 atomic% based on the total amount of vanadium in oxidation state +3, vanadium in oxidation state +4, vanadium in oxidation state +5 in vanadium oxide, Of vanadium is 30 to 50 atomic%. Charge-discharge condition here is measured by applying a constant current (reference electrode (Ag / Ag +) compared to ^{-1.5 ~ 0.4V (Mg / Mg 2} + 1.5 ~ 3.4V) range 600mA / g (0.3C level in contrast).

The active material according to one embodiment can be used in a magnesium secondary battery, a sodium secondary battery, a lithium secondary battery, or the like.

The magnesium secondary battery replaces the rare metal lithium and is relatively inexpensive and uses a large amount of magnesium metal as the negative electrode. The magnesium ion is inserted into the positive electrode active material and is desorbed and discharged. The lithium secondary battery has a theoretical energy density It is more than double, low cost, stable in the atmosphere. And environmental, price competitiveness, and high energy storage characteristics, it is useful as a middle- or large-sized battery for electric power storage and electric vehicles, and has attracted attention as a next generation secondary battery.

The active material according to one embodiment is usable as a magnesium active material, for example, as a magnesium cathode active material. When used as a cathode active material, the interfacial resistance between the cathode active material and the electrolyte is reduced after the initial and cycle repetition, and the resistance against the migration of magnesium ions is reduced by the presence of V ⁺³ . Therefore, the life characteristic is improved. Among them, when a nanosheet cathode active material is used, the surface area is increased as compared with the case of a nanotube, so that the interfacial resistance is further reduced and the capacity is increased.

On the other hand, the sodium secondary battery can be constituted by a cheap material, unlike the lithium secondary battery using a rare lithium compound, and can solve the supply concern of the battery material. By practically using this, it is expected that a large secondary battery can be supplied in large quantities have.

The sodium secondary battery has an anode capable of doping and dedoping sodium ions and a cathode capable of doping and dedoping sodium ions.

Lithium secondary batteries are widely used in fields such as cell phones, notebook computers, batteries for power generation facilities such as wind power and solar power, electric vehicles, uninterruptible power supplies, and household batteries due to high voltage, capacity and energy density.

The secondary battery according to one embodiment is as shown in Fig. 2 shows a cylindrical secondary battery.

2, the secondary battery 21 includes an anode 23, a cathode 22, and a separator 24. The positive electrode 23, the negative electrode 22 and the separator 24 described above are wound or folded and accommodated in the battery case 25. Then, electrolyte is injected into the battery case 25 and the cap assembly 26 is sealed to complete the ion secondary battery 21. The battery case may have a cylindrical shape, a rectangular shape, a thin film shape, or the like. For example, the secondary battery may be a large-sized thin-film battery. The secondary battery may be an ion secondary battery.

A separator may be disposed between the anode and the cathode to form a battery structure. The cell structure is laminated in a bi-cellular structure, then impregnated with an organic electrolytic solution, and the resultant product is received in a pouch and sealed to complete a polymer battery.

A plurality of the electrical structures are stacked to form a battery pack. These battery packs can be used in all devices requiring high capacity. For example, a notebook, a smart phone, an electric vehicle, and the like.

Hereinafter, each component constituting the secondary battery will be described in more detail.

[anode]

According to an embodiment of the present invention, there is provided a positive electrode active material comprising a vanadium oxide represented by the following formula (1), wherein vanadium of the vanadium oxide has a mixed oxidation state of a plurality of oxidation states and an oxidation state of +3 do.

[Chemical Formula 1]

VO _x

1.5 < x < 2.5 in the general formula (1).

The vanadium of the vanadium oxide has a mixed oxidation state of three oxidation numbers, for example, a mixed oxidation state of oxidation number 3, oxidation number 4 and oxidation number 5.

1.9? X < 2.2 in the above formula (1).

According to one embodiment, the average oxidation number of the active material is from 3.8 to 4.3, for example from 3.99 to 4.26.

In Formula 1, x is specifically from 1.995 to 2.13.

The anode can be prepared according to the following procedure.

For example, a cathode active material composition in which a cathode active material, a conductive agent, a binder and a solvent are mixed is prepared. The positive electrode active material composition is directly coated on the metal current collector to produce a positive electrode plate. Alternatively, the cathode active material composition may be cast on a separate support, and then the film peeled from the support may be laminated on the metal current collector to produce a cathode plate. The anode is not limited to those described above, but may be in a form other than the above.

As the conductive agent of the cathode active material composition, metal powders such as acetylene black, Ketjen black, natural graphite, artificial graphite, carbon black, carbon fiber, copper, nickel, aluminum and silver, metal fibers and the like can be used. And the like can be used alone or in admixture of one or more kinds. However, any conductive material can be used as long as it can be used as a conductive agent in the technical field of the present invention.

Examples of the binder include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer including ethylene oxide, polyvinyl pyrrolidone At least one selected from polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, polyamideimide, acrylated styrene-butadiene rubber, epoxy resin and nylon But are not limited to, and can be used as long as they can be used in the art as a binding agent.

As the solvent, N-methylpyrrolidone, acetone, water or the like may be used, but not limited thereto, and any solvent which can be used in the technical field can be used.

The content of the cathode active material, the conductive agent, the binder and the solvent is a level commonly used in a secondary battery. One or more of the conductive agent, the binder and the solvent may be omitted depending on the use and configuration of the secondary battery.

In the case of a magnesium secondary battery, the anode may further include a conventional cathode active material. Here, the typical amount of the cathode active material is 50 to 98 parts by weight based on 100 parts by weight of the total weight of the cathode active material.

The positive electrode active material includes a transition metal compound or a magnesium composite metal oxide capable of intercalating and deintercalating magnesium ions. Oxides, sulfides or halides of metals selected from the group consisting of scandium, ruthenium, titanium, vanadium, molybdenum, chromium, manganese, iron, cobalt, nickel, copper and zinc and magnesium and composite metal oxides And may include one or more.

For example, TiS ₂ , ZrS ₂ , RuO ₂ , Co ₃ O ₄ , Mo ₆ S ₈ , and V ₂ O ₅ may be used as the positive electrode active material, but the present invention is not limited thereto. (M _{1 -x} A _x ) O ₄ (0? _X ? 0.5, M is Ni, Co, Mn, Cr, V, Fe, Cu or Ti; A is at least one element selected from the group consisting of Al, B , Si, Cr, V, C, Na, K, or Mg) may be used.

In the case of a magnesium secondary battery, the current collector should be stable without causing electrochemical changes in the battery. When the current collector is corroded, the current collecting ability can not be exhibited as the battery cycle is repeated, thereby shortening the life of the battery.

The current collector is preferably made of stainless steel. For example, a material in which a primer including a conductive material and a polymer material is coated on a metal substrate.

The metal base material is a metal that is stable at the potential of the magnesium secondary battery and is not particularly limited as long as it can serve to supply and deliver electrons. For example, stainless steel, nickel, titanium, Such a metal substrate has a thickness of about 1 to 150 mu m and can be formed into various shapes such as foil, film, sheet, net, porous body, foam, and the like. May be in the form of a foil.

The primer serves to increase the adhesion of the cathode active material to the metal substrate while suppressing the increase of the internal resistance to the maximum. For example, the primer may include a conductive material and a polymer material in a weight ratio of 1:10 to 10: 1. When the content of the conductive material is in the above range, it is possible to provide a desired adhesive force without decreasing the operating characteristics of the battery by increasing the internal resistance.

The conductive material may include at least one selected from the group consisting of graphite, carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, The present invention is not limited thereto. Among them, carbon black is mainly used. The particle diameter of the conductive material is 10 to 100 nm.

The polymer material may be, for example, a polyimide-based copolymer, an acrylate-based copolymer, polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, At least one member selected from the group consisting of polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene- But is not limited to these. Among them, a polyimide-based copolymer is used.

The layer thickness of the primer is, for example, 100 nm to 1 占 퐉. The shape of the layer may be in the form of a film having a uniform thickness or in the form of a cluster having a non-uniform thickness. For example, the cluster type primer layer has a high specific surface area, so it provides a better adhesion force than the film type primer layer when attaching the cathode active material. In the case of forming such a cluster type primer layer, stainless steel may be used as the metal base material.

The primer can be formed on one side or both sides of the current collector, and according to one embodiment, it is formed on both sides.

The method of adding the primer to the surface of the current collector may be, for example, a method of adding a conductive material and a high molecular material to a predetermined volatile solvent to form a coating liquid, applying the coating liquid to the current collector, and then removing the solvent have. Examples of the volatile solvent include NMP, water, MIBK (methyl isobutyl ketone), and isopropanol, but are not limited thereto.

In the case of a sodium secondary battery, the positive electrode is a positive electrode active material, which is vanadium oxide represented by the formula (1) according to an embodiment. In addition to the active material having vanadium in the vanadium oxide mixed oxidation state of the oxidation number 3, the oxidation number 4 and the oxidation number 5, And a cathode active material for a secondary battery. Here, the typical amount of the cathode active material is 50 to 98 parts by weight based on 100 parts by weight of the total weight of the cathode active material.

As the positive electrode active material, Ag ₂ S, As ₂ S ₃ , CdS, CuS, Cu ₂ S, FeS, FeS ₂ , HgS, MoS ₂ , Ni ₃ S ₂ , NiS, NiS ₂ , PbS, TiS ₂ , MnS, Sb ₂ S ₃ , a mixture of the metal sulfide and the transition metal, and the like. The transition metal may be at least one selected from Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, , W, Re, Os, Ir, Pt, Au, Hg, Lr, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg and Uub.

In the case of a lithium secondary battery, the anode may further include a cathode active material for a lithium secondary battery in addition to the vanadium oxide described above. Here, the typical amount of the cathode active material is 70 to 98 parts by weight based on 100 parts by weight of the total amount of the cathode active material.

The typical cathode active material may include at least one selected from the group consisting of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, and lithium manganese oxide, but not always limited thereto Any cathode active material available in the art may be used.

For example, Li _a A _{1 - b} B _b D ₂ , wherein 0.90 ≤ a ≤ 1.8, and 0 ≤ b ≤ 0.5; Li _a E _{1 -b} B _b O _{2 -c} D _c wherein, in the formula, 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05; LiE _{2 - b} B _b O _{4 - c} D _{c where} 0? B? 0.5, 0? C? 0.05; Li _a Ni _{1 -b- c} Co _b B _c D _? Wherein, in the formula, 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _{1 - b - c} Co _b B _c O _{2 - ?} F _{? Wherein the} 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _{1 -b- c} Co _b B _c O _{2 - ?} F ₂ wherein 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _{1 -b- c} Mn _b B _c D _? Wherein, in the formula, 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _{1 -b- c} Mn _b B _c O _{2 - ?} F _{? Wherein} , in the formula, 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _{1 -b- c} Mn _b B _c O _{2 - ?} F ₂ wherein 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _b E _c G _d O ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, and 0.001 ≤ d ≤ 0.1; Li _a Ni _b Co _c Mn _d GeO ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, and 0.001 ≤ e ≤ 0.1; Li _a NiG _b O ₂ (in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1); Li _a CoG _b O ₂ wherein, in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1; Li _a MnG _b O ₂ (in the above formula, 0.90? A? 1.8, 0.001? B? 0.1); Li _a Mn ₂ G _b O ₄ wherein, in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1; QO _2; QS ₂ ; LiQS ₂ ; V ₂ O ₅ ; LiV ₂ O ₅ ; LiIO ₂ ; LiNiVO _4; Li _(3-f) J ₂ (PO ₄ ) ₃ (0? F? 2); Li _(3-f) Fe ₂ (PO ₄ ) ₃ (0? F? 2); In the formula of LiFePO ₄ may be used a compound represented by any one:

In the above formula, A is Ni, Co, Mn, or a combination thereof; B is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or combinations thereof; Q is Ti, Mo, Mn, or a combination thereof; I is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

Of course, a compound having a coating layer on the surface of the compound may be used, or a compound having a coating layer may be mixed with the compound. The coating layer may comprise an oxide, a hydroxide of the coating element, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, or a coating element compound of the hydroxycarbonate of the coating element. The compound constituting these coating layers may be amorphous or crystalline. The coating layer may contain Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr or a mixture thereof. The coating layer forming step may be any coating method as long as it can coat the above compound by a method which does not adversely affect the physical properties of the cathode active material (for example, spray coating, dipping, etc.) by using these elements, It will be understood by those skilled in the art that a detailed description will be omitted.

For example, LiNiO ₂ , LiCoO ₂ , LiMn _x O _2x (x = 1 or 2), LiNi _{1 -x} Mn _x O ₂ (0 <x <1), LiNi _{1 -xy} Co _x Mn _y O ₂ ? 0.5, 0? Y? 0.5), LiFeO ₂ , V ₂ O ₅ , TiS, MoS and the like can be used.

The positive electrode collector of the lithium secondary battery is not particularly limited as long as it has a thickness of 3 to 500 탆 and has a high conductivity without causing chemical change in the battery. For example, stainless steel, aluminum, , Heat-treated carbon, or a surface treated with carbon, nickel, titanium, silver or the like on the surface of aluminum or stainless steel can be used. The current collector may have fine irregularities on the surface thereof to increase the adhesive force of the cathode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

[cathode]

In the case of a magnesium secondary battery, the negative electrode may include, but is not necessarily limited to, a magnesium metal, a magnesium metal-based alloy, or a magnesium intercalating compound. The negative electrode may be used as an anode active material in the technical field, and may include magnesium, or any material capable of absorbing / desorbing magnesium.

The cathode may be, for example, magnesium metal. Examples of the magnesium-based alloy include alloys of aluminum, tin, indium, calcium, titanium, vanadium, and the like and magnesium.

For example, the negative electrode may be used in a variety of forms such as a film, a sheet, a foil, a net, a porous body, a foam, a nonwoven fabric, and the like.

In the case of a sodium secondary battery, an electrode including a sodium metal or a sodium alloy, or an electrode in which a sodium metal or a sodium alloy is laminated on a current collector may be used as the cathode. As the cathode, an electrode having a sodium inorganic compound (hereinafter referred to as &quot; sodium compound &quot;) capable of doping and undoping sodium ions can be used.

As the sodium compound is NaFeO _2, NaMnO _2, NaNiO ₂ and NaCoO ₂ such as an oxide represented by _a NaM1 O ₂ of (M1 is a transition metal element at least _{one, 0≤a <1), Na 0} .44 Mn 1 - oxide represented by _{a a} O ₂ M1 (M1 is a transition metal element at least _{one, 0≤a <1), Na 0} .7 Mn 1 - a M1 a O oxide represented by _{2 .05} (M1 is at least one Transition metal element, 0? A <1); An oxide represented by Na _b M2 _c Si ₁₂ O ₃ 0 such as Na ₆ Fe ₂ Si ₁₂ O ₃ 0 and Na ₂ Fe ₅ Si ₁₂ O ₃ 0 (M2 is at least one transition metal element, 2? B? 6, 2? C? 5); Na ₂ Fe ₂ Si ₆ O ₁₈ and Na ₂ MnFeSi ₆ O _18, etc. of Na _d M3 _e Si ₆ O ₁₈ oxide represented by (M3 is a transition metal element at least one, 3≤d≤6, 1≤e≤2 ); Na ₂ FeSiO ₆ such as Na _f M4 _g Si oxide represented by ₂ O ₆ (M4 is a transition metal element, at least one element selected from the group consisting of Mg, Al, 1≤f≤2, 1≤g≤2 ); Phosphates such as NaFePO ₄ and Na ₃ Fe ₂ (PO ₄ ) ₃ ; Borates such as NaFeBO ₄ and Na ₃ Fe ₂ (BO ₄ ) ₃ ; Na ₃ FeF ₆ and Na ₂ MnF ₆ (M ₅ is at least one transition metal element, ₂ ≦ _h ≦ ₃ ) represented by Na _h M ₅ F ₆ .

In the case of a lithium secondary battery, examples of the negative electrode include a carbon-based material such as graphite and carbon, a lithium metal, an alloy thereof, Si, SiOx (0 <x <2, for example, 0.5 to 1.5), Sn, SnO ₂ , And a mixture thereof may be used.

The silicon alloy may be manufactured using at least one of silicon and at least one of Al, Sn, Ag, Fe, Bi, Mg, Zn, in, Ge, Pb and Ti.

The negative electrode active material may include lithium-alloyable metals / metalloids, alloys thereof, or oxides thereof. For example, the metal / metalloid capable of alloying with lithium may be at least one selected from the group consisting of Si, Sn, Al, Ge, Pb, Bi, Sb Si-Y alloy (Y is an alkali metal, an alkaline earth metal, a Group 13 element, (Y is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, a rare earth element, or a combination element thereof, and is a metal, a rare earth element or a combination element thereof, Sn), and the like. The element Y may be at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Se, Te, Po, or a combination thereof. For example, the oxide of the metal / metalloid capable of alloying with lithium may be lithium titanium oxide, vanadium oxide, lithium vanadium oxide, SnO ₂ , SiO _x (0 <x <2) and the like.

The negative electrode active material may be a composite of graphite and a selected one of silicon, silicon oxide and silicon alloy as described above, or a mixture of graphite and one selected from the above-described silicon, silicon oxide, and silicon alloy.

For example, the shape of the negative electrode active material may be a simple particle shape or a nanostructure having a nano-sized shape. For example, the anode active material may have various shapes such as nanoparticles, nanowires, nano-rods, nanotubes, and nanobelt.

For example, the negative electrode may be a metal in a metal state generally having a thickness of 3 to 500 μm, and may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric.

According to another embodiment, a negative electrode for a secondary battery can be manufactured as follows.

For example, the negative electrode active material composition containing the negative electrode active material, the conductive agent and the binder may be formed into a predetermined shape or the negative electrode active material composition may be applied to a current collector such as copper foil.

The negative electrode active material is a negative electrode active material for a magnesium secondary battery, a sodium secondary battery or a lithium secondary battery.

Specifically, an anode active material composition in which the anode active material, the conductive agent, the binder and the solvent are mixed is prepared. The negative electrode active material composition is directly applied on the metal current collector to produce a negative electrode. Alternatively, the negative electrode active material composition may be cast on a separate support, and then the film peeled off from the support may be laminated on the metal current collector to produce a negative electrode. The negative electrode is not limited to the above-described form, but may be in a form other than the above-described form.

The content of the binder in the negative electrode active material may be 1 to 10 parts by weight, for example, 1 to 3 parts by weight based on 100 parts by weight of the total weight of the negative electrode active material composition.

The method of applying the negative electrode active material composition to the current collector is selected according to the viscosity of the composition and is selected from the group consisting of a screen printing method, a spray coating method, a coating method using a doctor blade, a gravure coating method, a dip coating method, a silk screen method, And a coating method using a slot die.

The collector is not particularly limited as long as it has electrical conductivity without causing chemical change in the secondary battery. For example, carbon, stainless steel, aluminum, nickel, titanium, sintered carbon, copper, Nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used.

In addition, fine unevenness may be formed on the surface to enhance the bonding force of the electrode active material, and it may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, or a nonwoven fabric.

The current collector is generally made to have a thickness of 3 to 20 mu m.

After the negative electrode active material composition is coated on the current collector and / or the substrate, the negative electrode may be obtained by performing a first heat treatment at 80 to 120 ° C to remove the solvent, followed by a rolling process, and then drying .

During the first heat treatment, water as a solvent is removed from the electrode. When the temperature during drying is in the above range, generation of bubbles on the surface of the electrode is suppressed and an electrode having excellent surface uniformity can be obtained. The drying can be carried out in an air atmosphere.

The secondary heat treatment can be performed under the vacuum after the primary heat treatment. The second heat treatment is performed at 100 to 200 ° C under a vacuum of 1 × 10 ^-4 to 1 × 10 ^-6 torr.

The negative active material composition may further include a carbon-based negative active material in addition to the negative active material.

For example, the carbon-based negative electrode active material may be, for example, crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon may be graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake, spherical or fibrous shape, and the amorphous carbon may be soft carbon or hard carbon carbon fiber, carbon fiber, mesophase pitch carbide, calcined coke, graphene, carbon black, fullerene soot, carbon nanotubes, and carbon fiber, but not necessarily limited thereto, Anything that can be used is possible.

As the conductive agent, at least one selected from metal powders such as acetylene black, Ketjen black, natural graphite, artificial graphite, carbon black, carbon fiber, copper, nickel, aluminum and silver, metal fibers and polyphenylene derivatives may be mixed and used But are not limited to, and may be used as long as they can be used as a conductive material in the art.

The negative electrode may further include a conventional binder in addition to the above-described binder. For example, conventional conventional binders include sodium-carboxymethylcellulose (Na-CMC), alginic acid derivatives, chitosan derivatives, polyvinyl alcohol (PVA), polyacrylic acid (PAA) Polyvinylidene fluoride (PVDF), polyvinylidene fluoride (PVA), polyvinylidene fluoride (PVA), polyvinylidene fluoride (PVA), polyvinylidene fluoride ), Polyacrylonitrile (PAN), water-dispersed styrene-butadiene rubber (SBR), water-dispersed butadiene rubber (BR), and modified products thereof such as fluorine-substituted A random copolymer, a block copolymer, or an alternating copolymer of a polymer, a polymer in which a sulfonic group (-SO ₂ -) is substituted in the main chain thereof, or a polymer in which the polymer is substituted with a sulfone group (-SO ₂ -) or other polymer may be used. And can be used as a binder in the art Both can be used.

The current collector is not particularly limited as long as it has electrical conductivity without causing chemical changes in the secondary battery. For example, the collector may be formed of a metal such as carbon, , Nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used.

In addition, fine unevenness may be formed on the surface to enhance the bonding force of the electrode active material, and it may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, or a nonwoven fabric.

[Separator]

The secondary battery may include a separator interposed between the anode and the cathode.

The separator is interposed between the positive electrode and the negative electrode, and an insulating thin film having high ion permeability and mechanical strength is used.

The pore diameter of the separator is generally 0.01 to 10 mu m, and the thickness is generally 5 to 20 mu m. As such a separator, for example, an olefin-based polymer such as polypropylene having chemical resistance and hydrophobicity; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

Specific examples of the olefin-based polymer may include polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more thereof, and examples thereof include a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three- A polyethylene / polypropylene three-layer separator, or the like can be used.

For example, a separator can be produced according to the following method.

A polymer resin, a filler and a solvent are mixed to prepare a separator composition. The separator composition may be directly coated on the anode active material layer and dried to form a separator. Alternatively, after the separator composition is cast and dried on a support, a separator film peeled off from the support may be laminated on the negative active material layer to form a separator.

The polymer resin used in the production of the separator is not particularly limited, and any material used for the binder of the electrode plate may be used. For example, polyethylene, polypropylene, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate or mixtures thereof may be used. The filler may be an inorganic particle or the like, and the solvent may dissolve the polymer resin and form pores in the polymer resin upon drying, so long as it is generally used in the art.

Further, the separator may be separately manufactured by another publicly known method and laminated on the anode active material layer. For example, a dry manufacturing method in which a microporous film is formed by forming a film by melting and extruding polypropylene or polyethylene, annealing at a low temperature to grow a crystal domain, and then stretching in this state to extend an amorphous region Can be used. For example, a film obtained by mixing a low-molecular material such as a hydrocarbon solvent with polypropylene, polyethylene, or the like, and then forming a film, and then a solvent or a small molecule is gathered to form an island phase, A wet production method of forming a microporous membrane by removing a solvent or a low molecular weight using another volatile solvent may be used.

The separator may additionally contain additives such as non-conductive particles, other fillers, and fiber compounds for the purpose of controlling strength, hardness and heat shrinkage. For example, the separator may further include inorganic particles. By further including the inorganic particles, the oxidation resistance of the separator is improved, and deterioration of the battery characteristics can be suppressed.

The inorganic particles may be alumina (Al ₂ O ₃ ), silica (SiO ₂ ), titania (TiO ₂ ), or the like. The average particle diameter of the inorganic particles may be 10 nm to 5 占 퐉. When the average particle diameter is within the above range, inorganic particle dispersion can be smoothly performed without deteriorating the crystallinity of the inorganic particles.

The separator may have a multi-layer structure including at least one polymer layer for the purpose of increasing the tear strength and the mechanical strength. For example, a polyethylene / polypropylene laminate, a polyethylene / polypropylene / polyethylene laminate, a nonwoven fabric / polyolefin laminate, and the like.

[Electrolyte]

When the secondary battery is a lithium secondary battery, the electrolyte includes a non-aqueous electrolyte and a lithium salt. In the secondary battery of Fig. 1, a non-aqueous liquid electrolyte may be used as the electrolyte.

As the non-aqueous electrolyte, a non-aqueous electrolyte, an organic solid electrolyte, an inorganic solid electrolyte and the like are used.

Examples of the nonaqueous electrolytic solution include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylenecarbonate, dimethyl carbonate, diethyl carbonate, gamma-butyrolactone, 1,2-dimethoxyethane Dimethylformamide, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethylacetate, trimethylolpropane, trimethylolpropane, trimethylolpropane, trimethylolpropane, Propylenecarbonyl derivatives, tetrahydrofuran derivatives, ethers, methyl pyrophosphate, ethyl propionate, or fluoro (meth) acrylates, such as methoxymethane, dioxolane derivatives, sulfolane, methyl sulfolane, Ethylene carbonate (FEC) may be used.

Examples of the organic solid electrolyte include a polymer including a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, and an ionic dissociation group Can be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Li ₄ SiO ₄ -LiI- Li ₃ PO ₄ -Li ₂ S-SiS ₂ can be used.

The lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF _{6, LiSbF 6, LiAlCl 4,} CH 3 SO 3 Li, (CF 3 SO 2) 2 NLi, such as chloroborane lithium, lower aliphatic carboxylic acid lithium, tetrakis phenyl lithium borate, may be used. For the purpose of improving charge / discharge characteristics, flame retardancy, etc., non-aqueous electrolytes may be used in the form of, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride and the like are added It is possible. In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability, or a carbon dioxide gas may be further added to improve high-temperature storage characteristics.

The concentration of the lithium salt is 0.1 to 2M, for example, 0.5 to 1.5M. When the concentration of the lithium salt is in this range, the capacity and life characteristics of the secondary battery are excellent.

If a solid electrolyte such as a polymer electrolyte is used as the electrolyte, the solid electrolyte may also serve as the separator. In this case, therefore, no separate separator is required.

In the case of a magnesium secondary battery, the electrolyte includes a magnesium salt and a non-aqueous organic solvent. The electrolyte of the magnesium secondary battery can be used as long as it can form an electrochemically stable electrolyte at a voltage of 1 V or more with respect to magnesium for stable operation. The magnesium salt is, for example, RMgX (wherein R is a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkyl group having 6 to 10 carbon atoms, or a linear or branched amine having 1 to 10 carbon atoms group a), MgX ₂ (X is a halogen atom), R ₂ Mg (R is a C1 to group 20 alkyl group, a dialkyl boron having 1 to 20 carbon atoms of, diaryl boronic having 6 to 20 carbon atoms group, a C 1 -C An alkylsulfonyl group having 1 to 20 carbon atoms or an alkylsulfonyl group having 1 to 20 carbon atoms, MgClO _4, etc. may be used alone or in admixture of two or more.

In RMgX, R is specifically a methyl group, an ethyl group, a butyl group, a phenyl group, or an aniline group, and X is a halogen atom, for example, chlorine or bromine. And X of MgX ₂ is, for example, chlorine or bromine.

The alkylcarbonyl group in R ₂ Mg is, for example, a methylcarbonyl group (-CO ₂ CH ₃ ), and the alkylsulfonyl group is, for example, a trifluoromethylsulfonyl group (-SO ₂ CF ₃ ).

Magnesium salts are particularly Mg (AlCl ₂ BuEt) ₂ (an abbreviation of Bu is butyl, Et is being stands for an ethyl _{group), Mg (ClO 4) 2} , Mg (PF 6) 2, Mg (BF4) 2, Mg _{(CF 3 SO 3) 2,} MgN (CF 3 SO 2), MgN (C 2 F 5 SO 2) 2, MgC (CF 3 SO 2) ₃ or the like is used.

The concentration of the magnesium salt can be suitably set in consideration of the solubility of the electrolyte with respect to the electrolytic solution, and is usually 0.2 to 5 M, for example, 0.3 to 3 M, specifically 0.8 to 1.5 M. When the concentration of the magnesium salt is in the above range, the magnesium secondary battery has excellent internal resistance characteristics.

The non-aqueous organic solvent used in the magnesium secondary battery has a high oxidation potential and is capable of dissolving the sodium salt. As specific examples, a carbonate-based solvent, an ester-based solvent, or an ether-based solvent is used. Examples of the solvent include propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate, N, N-dimethylformamide, N, N-dimethylformamide, tetrahydrofuran, tetrahydrofuran, -Dimethylacetamide, N, N-dimethylsulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, tetrahydrofuran, dimethyl ether or mixtures thereof .

Various additives may be added to the electrolyte as required. Specifically, for the purpose of improving the charge-discharge characteristics and the flame retardancy, there can be mentioned, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, hexamethylphosphoramide hexamethyl phosphoramide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, May be added. In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability.

The electrolyte for the magnesium secondary battery may specifically be a composition containing Mg (AlCl ₂ BuEt) ₂ / THF.

The electrolyte for a sodium secondary battery includes a sodium salt and a non-aqueous organic solvent.

Sodium salts can be used as long as they are commonly used in the art. For example, a sodium salt such as _{NaClO 4, NaPF 6, NaBF 4} , NaCF 3 SO 3, NaN (CF 3 SO 2) 2, NaN (C 2 F 5 SO 2) 2, NaC (CF 3 SO 2) 3 the .

The concentration of the sodium salt can be suitably set in consideration of the solubility of the electrolyte with respect to the electrolytic solution, and is 0.2 to 5 M, for example, 0.3 to 3 M, specifically 0.8 to 1.5 M. When the concentration of the sodium salt is in the above range, the internal resistance of the sodium secondary battery is excellent.

The non-aqueous organic solvent used in the electrolyte for the sodium secondary battery may be the same as the non-aqueous organic solvent of the electrolyte for the magnesium secondary battery, and the same additives may be further added.

The secondary battery according to the present invention is excellent in capacity and lifespan characteristics and can be used not only for a battery cell used as a power source for a small device but also for a middle- or large-sized battery pack or a battery module including a plurality of battery cells used as a power source for a medium- As a unit cell.

Examples of the medium and large devices include an electric vehicle (EV) including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV) E-bike, an electric motorcycle electric power tool electric power storage device including an electric scooter (E-scooter), but the present invention is not limited thereto.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Comparative Example  One

5 mmol of vanadium pentachloride and 5 mmol of octadecylamine were added to 5 ml of ethanol and the mixture was stirred for 2 hours. 15 ml of distilled water was added to the resulting mixture, which was stirred for 48 hours to obtain a hydrolyzed vanadium oxide component.

The reaction product was subjected to hydrothermal reaction at 180 ° C for 7 days in autoclave. When the reaction is complete, the reaction mixture is filtered to give a solid which is repeatedly washed with ethanol and hexane. The resulting product was vacuum-dried at 80 占 폚 to obtain vanadium oxide.

Comparative Example  2

The vanadium pentoxide (V ₂ O ₅ ) powder was used as it was.

Example  One

0.91 g of vanadium pentoxide (V ₂ O ₅ ) powder and 1.35 g of octadecylamine were dissolved in 5 ml of ethanol, followed by mixing, and 15 ml of water was added thereto to obtain a mixture. At this time, the mixing ratio of dinitrodiamide to octadecylamine was 1: 1.

The mixture was stirred.

10 ml of water was added to the mixture and placed in a Teflon lined stainless steel autoclave vessel and microwave-assisted solvothermal equipment (MARS 5) (microwave power: 800 W, frequency 2.45 GHz ) For 20 hours.

The reaction product was washed, filtered, and dried at 90 ° C. to obtain vanadium oxide VO _{2 .035} in which vanadium of +3 oxidation, vanadium + 4 oxidation, and vanadium + 5 oxidation exist.

Example  2

Except that the mixture ratio of vanadium pentoxide (V ₂ O ₅ ) powder and octadecylamine was changed at a molar ratio of 1: 0.75, vanadium in oxidation number +3, vanadium in oxidation number +4, Vanadium oxide (VO _1.995 ) in which +5 vanadium coexists was obtained.

Example  3

The procedure of Example 1 was repeated except that vanadium pentoxide (V ₂ O ₅ ) powder and octadecylamine were mixed at a molar ratio of 1: 0.5, vanadium in oxidation number +3, vanadium in oxidation number +4 and oxidation number + Vanadium oxide (VO _2.13 ) in which 5 vanadium was coexisted.

Comparative Production Example  1: Manufacture of magnesium secondary battery

The slurry was prepared by mixing vanadium oxide, carbon and polyvinylidene fluoride, which were obtained in accordance with Comparative Example 1, at a weight ratio of 6: 2: 2 and mechanically stirred together with N-methylpyrrolidone (NMP).

The slurry was applied to an upper portion of the aluminum current collector using an applicator to a thickness of about 150 mu m and dried at 120 DEG C to complete an electrode.

A magnesium electrode electrode having a circular shape with a diameter of 12 mm and Ag / 0.1N AgNO ₃ as a reference electrode were used as the counter electrode, and a beaker type three-electrode cell as a magnesium secondary battery was assembled. An acetonitrile solution of 0.5 M Mg (ClO ₄ ) ₂ was used as the electrolytic solution.

Comparative Production Example  2: Manufacture of sodium secondary battery

The vanadium oxide, carbon, and polyvinylidene fluoride, which were obtained in accordance with Comparative Example 2, were mixed at a weight ratio of 6: 2: 2, and the mixture was mechanically stirred together with NMP to prepare a slurry.

The slurry was applied to an upper portion of the aluminum current collector using an applicator to a thickness of about 150 mu m and dried at 120 DEG C to complete an electrode.

A 1 mm thick glass fiber separator (Whatman, GF / B) was used as a separator and a sodium thin film as a counter electrode. 1 M NaPF ₆ was dissolved in propylene carbonate (PC) solvent as an electrolyte To prepare a coin cell which is a sodium secondary battery.

Production Example  1-3: Magnesium secondary battery

A magnesium secondary battery was fabricated in the same manner as in Comparative Production Example 1 except that vanadium oxide of Example 1-3 was used instead of vanadium oxide of Comparative Example 1, respectively.

Production Example  4: Sodium secondary battery

A sodium secondary battery was produced in the same manner as in Comparative Production Example 2 except that the vanadium oxide of Example 1 was used instead of the vanadium oxide obtained in Comparative Example 2. [

Evaluation example  One: XPS (X- ray photoelectron spectroscopy ) analysis

1) Examples 1-3 and Comparative Example 1

XPS analysis of vanadium oxide according to Example 1-3 and Comparative Example 1 was conducted to investigate the oxidation number of vanadium.

As the XPS analyzer, Quantum 2000 Scanning ESCA Microprobe of Physical Electronics, Inc. was used and the source power was monochromatic Cu Kαλ = 1.54 Å having a beam diameter of 100 nm.

The XPS analysis results are shown in FIG. 3 and Table 1-3.

Table 2 below shows the ratio of the V2p3 orbital of Table 1 calculated using the integral values of V ⁺³ , V ⁺⁴ , and V ⁺⁵ . The average oxidation number of vanadium was calculated from the following Table 2 and shown in Table 3 below.

division atom% C1s N1s O1s V2p3 Comparative Example 1 70.01 3.67 18.44 7.87 Example 1 67.98 3.51 19.53 8.99 Example 2 68.09 3.53 19.31 9.06 Example 3 64.40 2.97 22.67 9.97

V ^{+ 5} V ⁺⁴ V ⁺³ Comparative Example 1 3.46 (44at%) 4.41 (56at%) - Example 1 2.60 (29 at%) 4.40 (49 at%) 1.99 (22 at%) Example 2 2.53 (28 at%) 3.87 (43at%) 2.66 (29 at%) Example 3 3.92 (39 at%) 4.72 (47 at%) 1.33 (13 at%)

Average oxidation number Comparative Example 1 5.0 Example 1 4.07 Example 2 3.99 Example 3 4.26

Referring to FIG. 3 and Table 1-3, it was confirmed that the vanadium oxide of Example 1-3 had V ⁺³ , unlike the case of Comparative Example 1. In addition, the vanadium oxide of Example 1-3 is predicted to increase in conductivity in the presence of V ⁺³ (d 2) as compared to the case of Comparative Example 1 (V ^{+ 5} (d 0)).

2) Production Example 1

The cell voltage was measured at 25 ° C in the magnesium secondary battery prepared in Preparation Example 1 at an open circuit voltage in the range of -0.1 to +0.1 V (= 2.9 to 3.1 V vs. Mg / Mg 2+) relative to the reference electrode (Ag / Ag + (= Mg / Mg &lt; 2 + &gt; + 1.5V) by applying a constant current of 600 mA / g and measuring the initial discharge capacity. Mg2 + &lt; / RTI &gt; 3.4 V).

The XPS analysis of the magnesium secondary battery of Production Example 1 was carried out before and after the charge / discharge and after the first cycle charge / discharge. As the XPS analyzer, Quantum 2000 Scanning ESCA Microprobe of Physical Electronics, Inc. was used, and the source power was monochromatic Al Kα (K-alpha: 1486.6 eV) having a beam diameter of 100 nm.

The XPS analysis results are shown in FIG. 4 and Table 4-5.

Table 5 below shows the peaks corresponding to V ⁺³ , V ⁺⁴ and V ⁺ 5 in V2p3 of Table 4

And the ratio is calculated by using the integral value.

division Atom% (at%) C1s O1s F1s Mg1s Cl2p V2p3 Before Charge / Discharge 79.97 12.44 2.71 0.14 0.00 4.74 After 1st charge / discharge 46.07 35.01 4.07 8.39 1.21 5.25

V ⁺⁴ V ^{+ 5} V ⁺³ Before Charge / Discharge 46.46 at% 24.21 at% 29.33 at% After Charge / Discharge 47.35 at% 35.09 at% 17.56 at%

From the above Tables 4 and 5, reversibility of V ⁺³ was confirmed after charge and discharge.

Evaluation example  2: Impedance measurement

The magnesium secondary batteries of Production Examples 1 and 3 and Comparative Production Example 1 were charged into a cell

Voltage is the reference electrode (Ag / Ag +) compared to -0.1 to + 0.1V range (Mg / Mg ^{+ 2} compared to 2.9 ~ 3.1V) from (Open circuit voltage) with a constant current applied to the 600mA / g -1.5V (Mg / Mg ^{2 +} to discharge until the contrast 1.5V), and then measure the initial discharge capacity, the charge 0.3 C until the final voltage on the reference electrode than 0.4V -1.5V (Mg / Mg ²⁺ than 3.4V) Respectively. Impedance was measured by using an impedance analyzer before charging / discharging and after charging / discharging by one cycle.

Impedance was measured before and after charging and discharging by AC impedance method, respectively.

The measurement results are shown in Fig. Fig. 6 is an enlarged view of the square area of Fig. 5. Fig.

Referring to this, it was found that the magnesium battery of Production Examples 1 and 3 had much improved impedance characteristics as compared with Comparative Production Example 1. Referring to FIG. 6, in the magnesium battery manufactured according to Production Example 3, the resistance Rct due to the charge transfer obtained by the impedance measurement of the electrode (unused electrode) before charge / The rate of increase of the resistance Rct due to the charge transfer obtained in the impedance measurement of the rear electrode was 100% or less, and the increase in the electron transfer resistance value once before and after the charging was remarkably lowered. On the other hand, the magnesium battery manufactured according to Comparative Production Example 1 exhibited a significantly increased resistance (Rct) due to charge transfer, which is obtained by impedance measurement, compared to before charging and discharging after charging and discharging .

Evaluation example  3: Electronic scanning microscope ( scanning electron microscope : SEM ) analysis

The vanadium oxides of Examples 1 and 3 and Comparative Example 1 were analyzed using a scanning electron microscope. Here, S-4700 of Hitachi was used as the SEM analyzer in the electron microscope.

The results of the analysis are shown in Figs. 7A and 7B to Figs. 9A and 9B. FIGS. 7A, 8A and 9A are SEM photographs of a 50,000 magnification SEM photograph of the vanadium oxide of Examples 1 and 3 and Comparative Example 1, and FIGS. 7B, 8B and 9B are SEM photographs of vanadium oxide of Examples 1 and 3 and Comparative Example 1, It is a SEM image of 100,000 magnification.

As shown in Figs. 7A and 7B, the vanadium oxide of Example 1 exhibited nanotubes having open ends at both ends as in the case of Comparative Example 1 (Figs. 9A and 9B). The vanadium oxide of Example 3 has a nanosheet shape as shown in FIGS. 8A and 8B.

Evaluation example  4: Transmission electron microscope ( Transmission electron microscope : TEM ) analysis

The vanadium oxides of Examples 1 and 3 were subjected to TEM analysis. A Tecnai Titan from FEI was used as a TEM analyzer.

The results of the analysis are shown in Figs. 10A, 10B, 11A and 11B.

Figs. 10B and 11B are enlarged views of partial regions of Figs. 10A and 11A, respectively.

Referring to FIG. 10A, it was found that the vanadium oxide of Example 1 had a nanotube shape. 10b, the interlayer distance of the vanadium oxide nanotubes is about 2.8 nm.

Referring to FIG. 11A, it was confirmed that vanadium oxide has a nanosheet shape. As shown in FIG. 11B, it was confirmed that the nanosheet had 1-3 layers.

Evaluation example  5: XRD  analysis

X-ray diffraction analysis of the vanadium oxides of Examples 1-3 and Comparative Example 1

Respectively. The X-ray diffraction analysis was performed using a Rigaku RINT2200HF + diffractometer using Cu Kradiation (1.540598 Å).

The results of XRD analysis are shown in Fig.

Referring to Fig. The (001), (002) and (003) peaks are peaks related to the layered structure. (001) peak appears in the region of about 3.2 ± 0.3 ° in 2θ and the (002) peak appears in the region of about 6.2 ± 0.3 ° in 2θ. And the (003) peak appears at about 7.8 ± 0.2 ° in 2θ range.

The vanadium oxide of Example 3 showed little characteristic peaks in the region where 2? Is larger than 10 ° as compared with the case of Example 1 and Comparative Example 1. From this peak information, it can be seen that the vanadium oxide obtained according to Example 3 is a nano-sheet structure having a small number of layers.

In the XRD diffraction analysis graph, information on the shape of the vanadium oxide can be obtained when the (003) peak is absent. In the case of Example 1, there is a (003) peak, whereas in Example 3, there is no (003) peak. From this, it can be confirmed that Example 1 has a nanotube shape and Example 3 has a nanosheet structure.

Further, in the XRD analysis, (001) and (002) peaks are observed at 10 ° or less, the peak intensity ratio of (002) peak / (001) is 0.5, and the half value width FWHM of the (001) peak is 0.33. It was found that vanadium oxide is excellent in crystallinity and has a nanotube shape or a nanosheet shape in which the layer structure is developed in the (001) direction.

Evaluation example  6: Charging and discharging  characteristic

Charging / discharging characteristics were evaluated at 25 캜 using a charge / discharge tester (TOYO, model: TOYO-3100) and started from charging.

The discharge capacity was evaluated at the time of discharging until the voltage relative to the reference electrode (Ag / Ag +) became -1.5 V at a rate of 0.3 C (unit: 600 mA / g) in the first cycle (C-rate). Thereafter, it was rested for 10 minutes. Then, each of the cells was charged at a rate of 0.3C until the voltage of the reference electrode (Ag / Ag +) became + 0.4V. The current density during charging and discharging was about 600 mA / g in one cycle and about 600 mA / g in two cycles.

1) Production Example 1-3 and Comparative Production Example 1

To the magnesium battery cells of Production Examples 1-3 and Comparative Production Example 1,

Voltage is the reference electrode (Ag / Ag +) compared to -0.1 to + 0.1V range (Mg / Mg ^{+ 2} compared to 2.9 ~ 3.1V) from (Open circuit voltage) with a constant current applied to the 600mA / g -1.5V (Mg / Mg ^{2 +} to discharge until the contrast 1.5V), and then measure the initial discharge capacity, the charge 0.3 C until the final voltage on the reference electrode than 0.4V -1.5V (Mg / Mg ²⁺ than 3.4V) Respectively. The discharging capacity after discharging was measured and set as the initial discharging capacity. The charging and discharging process was repeated 20 times to evaluate the charging and discharging characteristics.

The capacity retention rate represents the rate of change of the discharge capacity after repeating 15 cycles with respect to the initial discharge capacity.

The above charge / discharge characteristics were evaluated and are shown in Table 6, and in Fig. 13 and Fig. In Fig. 14, A is for discharging capacity and B is for charging capacity.

division Initial discharge capacity (mAh / g)
@ RT Capacity retention rate (%) @ 15 cycles Comparative Production Example 1 124.3 (0.1 C) 27.4 Production Example 1 218.2 (0.2C) 71.3 Production Example 2 230.1 (0.2C) 39.9 Production Example 3 239.6 (0.2C) 52.6

Referring to Table 6 and FIG. 13, it can be seen that the initial discharge capacity of the magnesium secondary battery of Production Example 1-3 using vanadium oxide having V ⁺³ introduced therein was improved as compared with Comparative Production Example 1. This is due to the effect of reducing the resistance of magnesium ions with the introduction of V ⁺³ .

Also, with reference to Table 6 above, it was found that the capacity maintenance ratio of the magnesium secondary battery of Production Example 1-3 using vanadium oxide having V ⁺³ introduced therein was improved as compared with Comparative Production Example 1. 14, it was confirmed that the capacity retention ratio of the magnesium secondary batteries of Production Examples 1 and 3 was improved compared with the case of Comparative Production Example 1. From this, it can be seen that when V ⁺³ is added to vanadium oxide, the resistance of magnesium ions decreases, and the lifetime of the vanadium oxide is improved because the initial state retention ratio is increased even after charging and discharging.

2) Production Example 4 and Comparative Production Example 2

The sodium secondary batteries of Production Example 4 and Comparative Production Example 2 were supplied with a cell voltage of 2.0

(Na / Na +) at a constant current of 300 mA / g, discharging to such an extent, measuring the initial discharge capacity, and discharging at 0.5 C until the end-of-charge voltage reached 3.8 V.

The discharging capacity after discharging was measured and set as the initial discharging capacity. The charging / discharging process was repeated for 15 cycles to evaluate charge / discharge characteristics.

The capacity retention rate represents the rate of change of the discharge capacity after repeating 15 cycles with respect to the initial discharge capacity.

The above charge / discharge characteristics were evaluated and are shown in Table 7 and Fig. 15-16. In Fig. 16, A is for discharging capacity and B is for charging capacity.

division Initial discharge capacity (mAh / g)
@ RT Capacity retention rate (%) @ 15 cycles Comparative Production Example 2 29.9 19.6 Production Example 4 66.5 89.4

Referring to Table 7 and FIG. 15, it was found that the initial discharge capacity of the sodium secondary battery of Production Example 4 was improved as compared with Comparative Production Example 2.

Also, it can be seen from Table 7 and FIG. 15 that the life characteristics of the sodium secondary battery of Production Example 4 are improved as compared with the case of Comparative Production Example 2.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, and that various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art. It will be understood that various modifications can be made by those skilled in the art without departing from the spirit and scope of the invention.

21: secondary battery 22: cathode
23: anode 24: separator
25: battery case 26: cap assembly

Claims (30)

And a vanadium oxide represented by the following formula (1)
Wherein the vanadium of the vanadium oxide has three mixed oxidation states of a plurality of oxidation numbers,
Wherein the oxidation number comprises an oxidation state of +3, +4, and +5,
[Chemical Formula 1]
VO _x
1.9? X < 2.2 in the formula (1). delete delete The method according to claim 1,
Wherein the vanadium oxide is a nanostructure. The method according to claim 1,
Wherein the vanadium oxide has a nanosheet or nanotube shape. 6. The method of claim 5,
Wherein the nanosheet comprises a single layer or a plurality of stacked layers
&Lt; / RTI &gt; 6. The method of claim 5,
Wherein the nanosheet has 1-10 layers,
Wherein the interlayer distance of the nanosheet is 2.5 to 3.5 nm. 6. The method of claim 5,
The nano sheet may be circular, oval, triangular, square, pentagonal, or
Active substance having a hexagonal shape. 6. The method of claim 5,
Wherein the nanotube is a multiwall nanotube. 6. The method of claim 5,
Wherein the nanotube is a nanotube having a length of 1 to 2 탆, an inner diameter of 15 to 50 nm, and an outer diameter of 50 to 100 nm. The method according to claim 1,
Wherein the content of vanadium in oxidation number +3 is 10 to 30 atomic% based on the total amount of vanadium in oxidation number +3, vanadium in oxidation number +4 and vanadium in oxidation number +5. The method according to claim 1,
Wherein the content of vanadium in the oxidation state +4 is 40 to 60 atomic%, and the content of vanadium in the oxidation state + 5 is 25 to 50 atomic%. delete The method according to claim 1,
X is 1.995 to 2.13 in the formula (1). The method according to claim 1,
(002) peak and (002) peak / (001) peak intensity ratio is 0.6 or less at 2θ of 10 ° or less in X-ray diffraction analysis,
And the half-value width (FWHM) of the (001) peak is 0.5 or less. Adding a reducing agent and a solvent to the starting material comprising vanadium to obtain a mixture; And
Applying an electromagnetic wave to the mixture to reduce the starting material to obtain a vanadium oxide represented by the following Formula 1,
Wherein the vanadium of the vanadium oxide has three mixed oxidation states of a plurality of oxidation numbers and the oxidation number of the vanadium oxide is +3, +4 and +5,
[Chemical Formula 1]
VO _x
1.9? X < 2.2 in the formula (1). 17. The method of claim 16,
Wherein the reducing agent is an amine-based material. 17. The method of claim 16,
Wherein the reducing agent is selected from the group consisting of octadecylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, heptadecyl An amine, and a hexadecylamine. 17. The method of claim 16,
Wherein the electromagnetic wave is a microwave. 20. The method of claim 19,
Wherein the microwave is applied at an output of 200 to 1500W and a frequency of 1 to 2.45 GHz. 17. The method of claim 16,
Wherein the reduction of the starting material is performed by a microwave hydrothermal reaction. 17. The method of claim 16,
Wherein the content of the reducing agent is 0.1 to 1 mole based on 1 mole of the vanadium oxide. 17. The method of claim 16,
Wherein the starting material containing vanadium is a vanadium pentoxide (V ₂ O ₅ ) powder or vanadium oxydiacetate (VO (Ac) ₂ ) An electrode comprising the active material of any one of claims 1, 4 to 12, 14 and 15. 24. A secondary battery comprising the electrode of Claim 24. 26. The method of claim 25,
Wherein the active material contained in the electrode of the secondary battery comprises vanadium oxide represented by the following Formula 1, and after the secondary battery is charged and discharged, the content of vanadium in the vanadium oxide of +3 is an amount of vanadium, Based on the total amount of vanadium, vanadium and vanadium of oxidation number + 5,
[Chemical Formula 1]
VO _x
1.9? X < 2.2 in the formula (1). 26. The method of claim 25,
The active material contained in the electrode of the secondary battery includes vanadium oxide represented by the following Formula 1, and after the charge and discharge of the secondary battery, the vanadium oxide has vanadium of +3 oxidation, vanadium of +4 oxidation, Wherein the content of vanadium in the oxidation state +4 is 40 to 60 atomic% and the content of vanadium in the oxidation state + 5 is 30 to 50 atomic% based on the total amount of vanadium,
[Chemical Formula 1]
VO _x
1.5 < x < 2.5 in the general formula (1). 26. A magnesium secondary battery comprising the electrode of claim 24. A sodium secondary battery comprising the electrode of Claim 24. A lithium secondary battery comprising the electrode of Claim 24

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