KR101622983B1 - Sodium-Metal Fluoride Secondary Battery and Manufacturing Method thereof - Google Patents

Abstract

The present invention relates to a sodium-metal fluoride secondary battery and a method of manufacturing the same, and is intended to provide a secondary battery having room temperature operability and having more stable electrochemical characteristics. The present invention relates to a negative electrode made of an inorganic material containing sodium, an electrolytic solution containing an electrolyte NaAlCl ₄ and a solvent sulfur dioxide, and a carbon-based material and a metal fluoride capable of generating and decomposing NaCl by the oxidation-reduction reaction of NaAlCl ₄ -xSO ₂ CuF ₂ ), and a method for producing the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sodium-metal fluoride secondary battery,

The present invention relates to a sodium-based secondary battery, and more particularly, to a sodium-metal fluoride secondary battery having room temperature operability and having more stable electrochemical characteristics and a method of manufacturing the same.

As consumers' demands have changed due to digitization and high performance of electronic products, market demand is changing due to the development of batteries with high capacity due to thinness, light weight and high energy density. In addition, in order to cope with future energy and environmental problems, hybrid electric vehicles, electric vehicles, and fuel cell vehicles are being actively developed.

Lithium secondary batteries have been put to practical use as batteries that can be miniaturized and lightweight and can be recharged with a high capacity, and are used in portable electronic devices such as portable video cameras, mobile phones, and notebook personal computers and communication devices. The lithium secondary battery is composed of an anode, a cathode, and an electrolyte. The lithium secondary battery is used to transfer energy while reciprocally moving both electrodes, such as lithium ions discharged from the cathode active material through charging, This is possible.

Recently, research on sodium-based secondary batteries using sodium instead of lithium has been reexamined. Since sodium is abundant in resource reserves, secondary batteries can be manufactured at low cost if sodium secondary batteries can be manufactured instead of lithium.

As described above, sodium-based secondary batteries are useful, but conventional sodium metal-based secondary batteries such as NAS (Na-S battery) and ZEBRA (Na-NiCl ₂ battery) can not be used at room temperature, There is a problem in battery safety due to the use of liquid sodium and positive electrode active material in the battery and degradation of battery performance due to corrosion problem. On the other hand, recently, a sodium ion battery using sodium ion decontamination has been actively studied, but their energy density and lifetime characteristics are still poor. Therefore, there is a demand for a sodium-based secondary battery which is usable at room temperature and is excellent in energy density and lifetime characteristics.

Accordingly, an object of the present invention is to provide a sodium secondary battery using a sulfur dioxide-based sodium-based inorganic liquid electrolyte as an ion conductor and at the same time using a metal fluoride as a cathode material to provide a room temperature operation type, high energy density, high output density, Metal fluoride-based secondary battery capable of securing low cost competitiveness and a method of manufacturing the same.

In order to accomplish the above object, the present invention provides a method for manufacturing a semiconductor device, comprising the steps of: providing a cathode and an anode including a metal fluoride; disposing an inorganic liquid electrolyte composed of sulfur dioxide (SO ₂ ) and a sodium salt between the anode and the cathode; - Construction of a method for manufacturing a metal fluoride-based secondary battery is disclosed.

Wherein the sodium salt is at least one of NaAlCl ₄ , NaGaCl ₄ , Na ₂ CuCl ₄ , Na ₂ MnCl ₄ , Na ₂ CoCl ₄ , Na ₂ NiCl ₄ , Na ₂ ZnCl ₄ and Na ₂ PdCl ₄ .

The inorganic liquid electrolyte has an SO ₂ molar ratio to sodium salt of 0.5 to 10, preferably 1.5 to 3.0.

Wherein the metal fluoride is selected from the group consisting of CuF ₂ , CuF, NiF ₂ , FeF ₂ , FeF ₃ , CoF ₂ , CoF ₃ , MnF ₂ , CrF ₂ , CrF ₃ , ZnF ₂ , ZrF ₄ , ZrF ₂ , TiF ₄ , TiF ₃ , NbF ₅ It may include _{AgF 2, SbF 3, GaF 3} , NbF 5 or one of two or more.

The content of the metal fluoride in the anode is 60 to 99 wt%.

The negative electrode is characterized in that the negative electrode is any one of a sodium metal, an alloy containing sodium, an intermetallic compound containing sodium, a carbonaceous material containing sodium, and an inorganic material containing sodium.

The inorganic material may include at least one of an oxide, a sulfide, a phosphide, a nitride, and a fluoride.

The content of the negative electrode material in the negative electrode is 60 to 100 wt%.

The anode may comprise a carbon material and a metal fluoride.

The anode is characterized in that the carbonaceous material contains 0-20 at% of one or more different kinds of elements.

The heteroelement includes nitrogen (N), oxygen (O), boron (B), fluorine (F), phosphorus (P), sulfur (S), and silicon (Si).

The present invention also discloses the structure of a sodium-metal fluoride-based secondary battery produced by the above-described production method.

The present invention also relates to a negative electrode of an inorganic material containing sodium, an electrolytic solution containing an electrolyte NaAlCl ₄ and a solvent sulfur dioxide, and a carbon-based material capable of generating and decomposing NaCl by oxidation-reduction reaction of NaAlCl ₄ -xSO ₂ A sodium-metal fluoride-based secondary battery comprising a positive electrode containing a metal fluoride.

According to the present invention, there is provided a method for producing a sodium-metal fluoride secondary battery and a sodium-metal fluoride secondary battery according to the present invention, which is characterized in that the sodium-metal fluoride secondary battery has novel high energy / It may be possible to secure expanded safety and price competitiveness.

1 is a view for explaining a sodium-metal fluoride-based secondary battery according to an embodiment of the present invention.
2 is a view illustrating a method of manufacturing a sodium-metal fluoride-based secondary battery according to an embodiment of the present invention.
3 is a graph showing a NaAlCl ₄ -xSO ₂ electrolytic solution Raman spectroscopic spectrum.
4 is a graph showing X-ray diffraction results of the metal fluoride anode.
5 is a graph showing charge / discharge curves of a sodium-metal fluoride secondary battery according to an embodiment of the present invention.
6 is a graph showing lifetime characteristics of a sodium-metal fluoride secondary battery according to an embodiment of the present invention.

In the following description, only parts necessary for understanding the operation according to the embodiment of the present invention will be described, and the description of other parts will be omitted so as not to disturb the gist of the present invention.

Also, the terms and words used in the present specification and claims should not be construed to be limited to ordinary or dictionary meanings, and the inventor is not limited to the concept of terms in order to describe his invention in the best way. It should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be properly defined. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely one preferred embodiment of the present invention, and not all of the technical ideas of the present invention are described. Therefore, It is to be understood that equivalents and modifications are possible.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic view of a configuration of a sodium-metal fluoride-based secondary battery 100 according to an embodiment of the present invention.

1, the sodium-metal fluoride secondary cell 100 of the present invention comprises a metal fluoride anode 3, a sodium-containing cathode 4, and a sulfur dioxide (SO ₂ ) Based inorganic liquid electrolyte (1), a case (5). The sodium-metal fluoride secondary battery 100 having such a structure may be a sodium-sulfur dioxide (Na-SO ₂ ) secondary battery in particular. The sodium-metal fluoride secondary battery 100 of the present invention is implemented so as to be able to operate even at room temperature based on the metal fluoride anode 3 and the sulfur dioxide-based inorganic liquid electrolyte 1.

The anode 3 comprises porous carbon and metal fluoride 2 and provides a place where the oxidation-reduction reaction of NaAlCl ₄ -xSO ₂ takes place. The metal fluoride (2) contained in the anode (3) is at least one selected from the group consisting of CuF ₂ , CuF, NiF ₂ , FeF ₂ , FeF ₃ , CoF ₂ , CoF ₃ , MnF ₂ , CrF ₂ , CrF ₃ , ZnF ₂ , ZrF ₄ , _2, TiF _4, may include _{TiF 3, NbF 5, AgF 2} , SbF 3, GaF 3, NbF 5 of one or two or more. In particular, in the present invention, the anode 3 may include a carbonaceous material and CuF ₂ at a constant weight ratio. CuF ₂ reacts with sodium ions while changing the oxidation number of Cu at the time of charging and discharging, thereby obtaining discharge products of Cu and NaCl, and reversibly reformation of CuF ₂ upon charging. The content of the metal fluoride (2) in the anode (3) is 50 to 100 wt% or 60 to 99 wt%, preferably 70 to 95 wt% for the purpose of compounding additional elements for improving the characteristics of the anode . The carbon material constituting the anode 3 may contain one or two or more different kinds of elements depending on the case. The heteroelement may include at least one of nitrogen (N), oxygen (O), boron (B), fluorine (F), phosphorus (P), sulfur (S), and silicon (Si). The content of the hetero-element is 0 to 20 at%, preferably 5 to 15 at%. When the content of heteroatom is less than 5 at%, the effect of increasing the capacity by adding the heteroatom is insignificant. When the content of 15 atomic percent or more is exceeded, the electrical conductivity of the carbon material and the ease of electrode formation are decreased.

The cathode 4 may be made of a sodium metal, an alloy containing sodium, an intermetallic compound containing sodium, a carbon material containing sodium, an inorganic material containing sodium, or the like. The inorganic material may include at least one of an oxide, a sulfide, a phosphide, a nitride, and a fluoride. The content of the cathode material in the cathode 4 may be 60 to 100 wt%.

The electrolyte and the sulfur dioxide-based inorganic liquid electrolyte (1) used as the anode active material may consist of NaAlCl ₄ (solute) and SO ₂ (solvent). The sulfur dioxide-based inorganic liquid electrolyte (1) has a molar ratio of SO ₂ to NaAlCl _{4 in a} molar ratio of 0.5 to 10, preferably 1.5 to 3.0. When the SO ₂ content molar ratio is lowered to less than 1.5, there is a problem that the electrolyte ion conductivity decreases, and when the molar ratio is higher than 3.0, the vapor pressure of the electrolyte is increased. In addition to NaAlCl ₄ used as a solute, NaGaCl ₄ , Na ₂ CuCl ₄ , Na ₂ MnCl ₄ , Na ₂ CoCl ₄ , Na ₂ NiCl ₄ , Na ₂ ZnCl ₄ , Na ₂ PdCl ₄ , , And NaAlCl ₄ exhibit comparatively excellent cell characteristics. The sulfur dioxide-based inorganic liquid electrolyte (1) can be produced by introducing SO ₂ gas into a mixture of NaCl and AlCl ₃ (or a salt of NaAlCl ₄ alone).

The case 5 may be provided to enclose the structure in which the sulfur dioxide-based inorganic liquid electrolyte 1 is disposed between the anode 3 and the cathode 4. [ A signal line connected to the anode 3 and a signal line connected to the cathode 4 may be disposed at one side of the case 5. The shape and size of the case 5 may be determined according to the field to which the sodium-metal fluoride secondary battery 100 is applied. The material of the case 5 may be made of a nonconductive material. When the insulator for enclosing the positive electrode 3 and the negative electrode 4 is provided, the case 5 may be formed of a conductive material.

FIG. 2 is a view illustrating a method of manufacturing a sodium-metal fluoride-based secondary battery 100 according to an embodiment of the present invention.

2, a method of manufacturing a sodium-metal fluoride secondary cell 100 according to the present invention includes steps S101 of providing an anode 3 and a cathode 4 including a metal fluoride 2, (S103) of inserting the anode (3) and the cathode (4) in which the sulfur dioxide-based inorganic liquid electrolyte (1) is disposed into the case (5) can do.

The step of providing the anode 3 in the step S101 includes the steps of providing a carbon material and metal fluoride 2 in which NaCl is formed and decomposed, stirring the carbon material and the metal fluoride 2, , And providing the anode 3 using the anode 3. The carbon material may be a carbon material in which NaCl is formed and decomposed, for example, among carbon materials such as natural graphite, artificial graphite, cokes, carbon black, pyrolytic carbon materials, carbon fibers, have. The shape of the carbon material may be, for example, a thin flake such as natural graphite, a spherical shape such as mesocarbon microbead, a fibrous shape such as graphitized carbon fiber, or an aggregate of fine powder. Here, the carbon material may serve as a conductive material.

The anode 3 may have a collector, and a cathode active material layer including a cathode active material and a binder formed on the surface of the collector. The positive electrode active material layer includes the positive electrode active material and the binder as described above. Use of a carbonaceous material as the positive electrode active material can suppress deterioration of battery performance. The preferable content of the carbonaceous material of the cathode active material is 60 to 100 wt% with respect to the mass of the cathode active material layer. The carbon material may contain 0 to 20 at% of one or more heteroatoms. Here, the heteroelement may include nitrogen (N), oxygen (O), boron (B), fluorine (F), phosphorus (P), sulfur (S), and silicon (Si).

The binder which can be used is not particularly limited and conventionally known binders may be used. Specific examples thereof include polyvinylidene fluoride (hereinafter also referred to as PVDF), polytetrafluoroethylene (hereinafter also referred to as PTFE), ethylene tetrafluoride, propylene fluoride, vinylidene fluoride copolymer, hexafluoropropylene fluoride Vinylidene copolymers, and tetrafluoroethylene / perfluoro vinyl ether copolymers. These may be used alone or in combination of two or more. Other examples of the binder include polysaccharides such as starch, methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylhydroxyethylcellulose, nitrocellulose, and the like And derivatives thereof. As the binder, inorganic fine particles such as colloidal silica and the like can be mentioned. The content of the binder is preferably 1 to 20% by mass, more preferably 1 to 10% by mass, based on the mass of the positive electrode active material layer.

In addition to the binder and the positive electrode active material, the positive electrode active material layer may further contain other components as long as the effect of the present invention is not impaired. For example, a conductive auxiliary agent, a support salt, and an ion conductive polymer. When an ion conductive polymer is included, a polymerization initiator for polymerizing the polymer may be included. The compounding ratio of these components is not particularly limited, and can be adjusted by appropriately referring to what is known about sodium-based secondary batteries.

The current collector is made of thin, mesh, expanded grids (expanded metal), punched metal, or the like using a conductive material such as nickel, copper, and stainless steel (SUS). The mesh of the mesh, the diameter of the line, and the number of meshes are not particularly limited and conventionally known ones can be used. The size of the current collector is determined depending on the intended use of the battery. When a large electrode used in a large-sized battery is manufactured, a large current collector is used. In the case of manufacturing a small electrode, a collector having a small area is used.

The step of providing the cathode 4 in the step S101 may be a step of providing an inorganic material containing sodium metal, an alloy containing sodium, an intermetallic compound containing sodium, or sodium. The content of the cathode material in the cathode 4 may correspond to 60 to 100 wt%.

In step S103, the step of preparing and disposing the sulfur dioxide-based inorganic liquid electrolyte 1 includes preparing sulfur dioxide (SO ₂ ) and sodium salt (NaAlCl ₄ ). The sodium salt may be NaAlCl ₄ , NaGaCl ₄ , Na ₂ CuCl ₄ , Na ₂ MnCl ₄ , Na ₂ CoCl ₄ , Na ₂ NiCl ₄ , Na ₂ ZnCl ₄ or Na ₂ PdCl ₄ . In the sulfur dioxide-based inorganic liquid electrolyte (1), the SO ₂ molar ratio with respect to NaAlCl ₄ may be 0.5 to 10, preferably 1.5 to 3.0.

In step S105, the sodium-metal fluoride-based secondary battery is manufactured by arranging the cathode 4, the sulfur dioxide-based inorganic liquid electrolyte 1, and the anode 3 in this order in the case 5 . In this process, the cathode 4 and the anode 3 are disposed at regular intervals in the case 5, the sulfur dioxide-based inorganic liquid electrolyte 1 is injected between the cathode and the anode, and then the case 5 is sealed .

The manufactured sodium-metal fluoride secondary battery may have a shape such as a circle, an ellipse, a rectangle, a rectangle with rounded corners, or the like. The shape of the battery may be, for example, a paper type, a coin type, a cylindrical shape, a prism shape, or the like.

3 is a graph showing the results of Raman spectroscopic analysis of a NaAlCl ₄ -xSO ₂ electrolyte.

Referring to FIG. 3, the NaAlCl ₄ -2 SO ₂ electrolyte obtained in the above-described manner exhibited a high sodium ion conduction characteristic close to 0.1 S / cm and remained in a liquid state exhibiting a relatively high conductivity even at a low temperature .

4 is a graph showing X-ray diffraction results of the metal fluoride anode.

Referring to FIG. 4, as a result of X-ray diffraction of a representative CuF ₂ anode in the metal fluoride anode, CuF ₂ reacts with sodium ions while changing the oxidation number of Cu at the time of charge and discharge to obtain a discharge product of CuF and NaCl, The CuF ₂ is reformed in reversed time. The content of CuF _{2 in} the CuF ₂ anode is 50 to 100 wt%, preferably 70 to 95 wt%.

5 is a graph showing charge / discharge curves of a sodium-metal fluoride secondary battery according to an embodiment of the present invention. 6 is a graph showing lifetime characteristics of a sodium-metal fluoride secondary battery according to an embodiment of the present invention. As described above, the negative electrode 4 used here is an alloy, an intermetallic compound, or an inorganic material including sodium metal or sodium. Inorganic materials include oxides, sulfides, phosphides, nitrides, fluorides, and the like.

Referring to FIGS. 5 and 6, the battery performance shows excellent battery capacity and operating voltage as a result of a representative Na-Metal Fluoride secondary battery employing a NaAlCl ₄ -2 SO ₂ electrolyte, a CuF ₂ anode, and a sodium metal type cathode . In FIG. 5, the voltage flat part represents the oxidation / reduction interval between CuF ₂ and CuF. FIG. 6 shows a high discharge voltage of 3.4 V and exhibits excellent lifetime characteristics.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

1: electrolyte
2: anode
3: cathode
4: Case
100: sodium-metal fluoride secondary battery

Claims (6)

A negative electrode made of a metal fluoride and a carbon-based material, and a negative electrode made of an inorganic material containing sodium;
And disposing an inorganic liquid electrolyte composed of sulfur dioxide (SO ₂ ) and a sodium salt between the anode and the cathode,
Wherein the inorganic liquid electrolyte has an SO ₂ molar ratio of 1.5 to 3.0 relative to the sodium salt. The method according to claim 1,
Wherein the sodium salt comprises at least one of NaAlCl ₄ , NaGaCl ₄ , Na ₂ CuCl ₄ , Na ₂ MnCl ₄ , Na ₂ CoCl ₄ , Na ₂ NiCl ₄ , Na ₂ ZnCl ₄ and Na ₂ PdCl ₄ . Method for manufacturing a metal fluoride based secondary battery. The method according to claim 1,
The metal fluoride
_{CuF 2, CuF, NiF 2,} FeF 2, FeF 3, CoF 2, CoF 3, MnF 2, CrF 2, CrF 3, ZnF 2, ZrF 4, ZrF 2, TiF 4, TiF 3, NbF 5, AgF 2, method for producing a metal fluoride-based secondary batteries - SbF _3, GaF _3, sodium comprising the NbF ₅ or one of two or more. The method according to claim 1,
The content of the metal fluoride in the anode is 60 to 99 wt%
Wherein the carbonaceous material of the anode contains at least one heteroatom of nitrogen (N), oxygen (O), boron (B), fluorine (F), phosphorus (P), sulfur (S) 15 at%, based on the total weight of the secondary battery. The method according to claim 1,
The negative electrode
Wherein the inorganic material is at least one selected from the group consisting of an oxide, a sulfide, a phosphide, a nitride, and a fluoride, wherein the inorganic material is selected from the group consisting of sodium metal, an alloy containing sodium, an intermetallic compound containing sodium, a carbonaceous material containing sodium, Lt; RTI ID = 0.0 > 1, < / RTI > An anode of an inorganic material containing sodium;
An electrolytic solution composed of electrolyte NaAlCl ₄ and a solvent sulfur dioxide;
And a cathode composed of a carbonaceous material and a metal fluoride, in which the formation and decomposition of NaCl are carried out by an oxidation-reduction reaction of NaAlCl ₄ -xSO ₂ ,
Wherein the inorganic liquid electrolyte has an SO ₂ molar ratio of 1.5 to 3.0 relative to the sodium salt.

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