KR101667247B1 - Sodium-Metal Bormide Secondary Battery and Manufacturing Method thereof - Google Patents

Abstract

The present invention relates to a sodium-metal bromide secondary cell 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 of an inorganic material containing sodium, an electrolytic solution containing an electrolyte NaAlCl ₄ and a solvent sulfur dioxide, and a carbon-based material in which NaCl is produced and decomposed by oxidation-reduction reaction of NaAlCl ₄ -xSO ₂ , (CuBr ₂ ), and a method for producing the same. The present invention also provides a sodium-metal bromide rechargeable battery including the same.

Description

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

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sodium-based secondary cell, and more particularly, to a sodium-metal bromide secondary cell having room temperature operability and having more stable electrochemical characteristics and a method for 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, and it is required to increase the size of batteries for automobile power sources.

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 method for producing a sulfur-based sodium-based inorganic liquid electrolyte by using an ionic conductor and simultaneously using a metal bromide as a cathode material to provide a room temperature operation type, high energy density, high output density, Metal bromide secondary battery and a method of manufacturing the same.

In order to achieve the above object, the present invention provides a process for preparing a positive electrode and a negative electrode comprising metal bromide, and a process for disposing an inorganic liquid electrolyte composed of sulfur dioxide (SO ₂ ) and a sodium salt between the positive electrode and the negative electrode A structure of a sodium-metal bromide secondary battery manufacturing method 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.

The metal bromide is _{CuBr 2, CuBr, NiBr 2,} FeBr 2, FeBr 3, CoBr 2, MnBr 2, CrBr 2, ZnBr 2, ZrBr 4, ZrBr 2, TiBr 4, TiBr 3, NbBr 5, AgBr, SbBr 3 , GaBr ₃ , BiBr ₃ , MoBr ₃ , SnBr ₂ , WBr ₆ , WBr ₅ , or the like.

The content of the metal bromide 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 carbonaceous material and a metal bromide.

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 bromide-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 bromide secondary battery comprising a positive electrode containing a metal bromide is provided.

According to the present invention, there is provided a method of manufacturing a sodium-metal bromide secondary cell and a sodium-metal bromide secondary cell according to the present invention. The present invention relates to a novel high energy / It may be possible to secure expanded safety and price competitiveness.

1 is a view for explaining a sodium-metal bromide-based secondary battery according to an embodiment of the present invention.
2 is a view illustrating a method of manufacturing a sodium-metal bromide secondary cell 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 a metal bromide anode.
5 is a graph showing charge / discharge curves of a sodium-metal bromide-based secondary battery according to an embodiment of the present invention.
6 is a graph showing lifetime characteristics of a sodium-metal bromide-based 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 bromide secondary cell 100 according to an embodiment of the present invention. Referring to FIG.

1, a sodium-metal bromide secondary cell 100 according to the present invention includes a metal bromide anode 3, a sodium-containing cathode 4, and a sulfur-containing gas SO 2, which include at least a metal bromide 2, ₂ ) -based inorganic liquid electrolyte 1, case 5. The sodium-metal bromide secondary battery 100 having such a structure may be a sodium-sulfur dioxide (Na-SO ₂ ) secondary battery in particular. The sodium-metal bromide-based secondary battery 100 of the present invention is implemented so as to be operable at room temperature based on the metal bromide anode 3 and the sulfur dioxide-based inorganic liquid electrolyte 1.

The anode 3 comprises porous carbon and metal bromide ₂ and provides a place where the oxidation-reduction reaction of NaAlCl ₄ -xSO ₂ takes place. The anode 3 is a metal bromide (2) CuBr _2, CuBr, NiBr _2, FeBr _2, FeBr _3, CoBr _2, MnBr _2, CrBr _2, ZnBr _2, ZrBr _4, ZrBr _2, TiBr contained in _4, TiBr ₃ , NbBr ₅ , AgBr, SbBr ₃ , GaBr ₃ , BiBr ₃ , MoBr ₃ , SnBr ₂ , WBr ₆ and WBr ₅ . In particular, in the present invention, the anode 3 may include a carbonaceous material and CuBr ₂ in a constant weight ratio. CuBr ₂ reacts with sodium ions while changing the oxidation number of Cu at the time of charging and discharging, thereby obtaining a discharge product of Cu and NaCl, and the CuBr ₂ is reversibly reversed upon charging. The content of the metal bromide (2) in the anode (3) is 50 to 100 wt% or 60 to 99 wt%, preferably 70 to 95 wt% in order to improve the properties of the anode (3) Lt; / RTI > 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 bromide 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 bromide-based secondary battery 100 according to an embodiment of the present invention.

2, the method for producing a sodium-metal bromide-based secondary battery 100 according to the present invention comprises the steps of: providing an anode 3 and a cathode 4 including a metal bromide 2; Step S105 of sealing the anode 3 and the cathode 4 in which the sulfur dioxide-based inorganic liquid electrolyte 1 is disposed in the case 5 and cutting it into a predetermined shape is performed during the step S103 of arranging and arranging the electrolyte 1 .

The step of preparing the anode 3 in the step S101 includes the steps of providing the carbon material and the metal bromide 2 in which NaCl is formed and decomposed, stirring the carbon material and the metal bromide 2, And forming the anode 3 by using the slurry. 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 manufacture of the sodium-metal bromide secondary cell can be carried out 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 bromide 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 a metal bromide anode.

Referring to FIG. 4, as a result of X-ray diffraction of a representative CuBr ₂ anode of a metal bromide anode, CuBr ₂ reacts with sodium ions while changing the oxidation number of Cu during charging and discharging, thereby obtaining a discharge product of CuBr and NaCl, CuBr ₂ is reformed reversibly upon charging. The content of CuBr _{2 in} the CuBr ₂ anode is 50 to 100 wt%, preferably 70 to 95 wt%.

5 is a graph showing charge / discharge curves of a sodium-metal bromide-based secondary battery according to an embodiment of the present invention. 6 is a graph showing lifetime characteristics of a sodium-metal bromide-based secondary battery according to an embodiment of the present invention. As described above, the negative electrode used herein 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 FIG. 5 and FIG. 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 CuBr ₂ anode, and a sodium metal type cathode . In FIG. 5, the voltage flat part indicates the oxidation / reduction interval between CuBr ₂ and CuBr. FIG. 6 shows a high discharge voltage of 3 V or higher and shows 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 bromide secondary battery

Claims (6)

Preparing a negative electrode comprising a positive electrode containing a metal bromide and a carbonaceous material and an inorganic material containing sodium;
And disposing an inorganic liquid electrolyte containing 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 METAL Bromide Type Secondary Battery). The method according to claim 1,
The metal bromide
_{CuBr 2, CuBr, NiBr 2,} FeBr 2, FeBr 3, CoBr 2, MnBr 2, CrBr 2, ZnBr 2, ZrBr 4, ZrBr 2, TiBr 4, TiBr 3, NbBr 5, AgBr, SbBr 3, GaBr 3, BiBr ₃ , MoBr ₃ , SnBr ₂ , WBr ₆ , WBr ₅ , or a mixture thereof. The method for producing a sodium-metal bromide secondary battery according to claim 1, The method according to claim 1,
The content of the metal bromide 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, Wherein the sodium-metal bromide-based secondary battery comprises one of the following. An anode of an inorganic material containing sodium;
An inorganic liquid electrolyte containing electrolyte NaAlCl ₄ and a solvent sulfur dioxide (SO ₂ );
And a cathode comprising a carbonaceous material and a metal bromide in which the formation and decomposition of NaCl are carried out by the oxidation-reduction reaction of NaAlCl ₄ -xSO ₂ ,
Wherein the inorganic liquid electrolyte has an SO ₂ molar ratio (x) relative to the NaAlCl ₄ of 1.5 to 3.0.

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