KR20230072752A - Cathode active material for zinc-ion secondary battery, zinc-ion secondary battery comprising same and method of manufacturing same - Google Patents

Abstract

The present invention relates to a cathode active material for a zinc-ion secondary battery represented by the following formula 1: Na_xV_yO_z (0 < x <=2, 1 <= y <=6, 1 <= z <= 15). A cathode active material for a zinc-ion secondary battery, a zinc-ion secondary battery comprising the same, and a manufacturing method thereof according to the present invention may have a high specific capacity of the zinc ion secondary battery (battery capacity per unit weight (mAh/g)) and excellent performance by easily and simply manufacturing a cathode active material using a sol-gel synthesis method and applying the manufactured cathode active material for the zinc-ion secondary battery.

Description

Cathode active material for zinc ion secondary battery, zinc ion secondary battery including the same, and manufacturing method thereof

The present invention relates to a cathode active material for a zinc ion secondary battery, a zinc ion secondary battery including the same, and a manufacturing method thereof, and more particularly, to a cathode active material for a zinc ion secondary battery that can be easily and simply prepared using a sol-gel synthesis method. , To provide a zinc ion secondary battery including the same and a manufacturing method thereof.

Water-based zinc secondary batteries use zinc, which is more than 7 times cheaper than lithium and has a high theoretical capacity (820 mAh/g), and uses water as an electrolyte solvent, so there is no risk of ignition. Currently, research on developing high-capacity cathode materials is underway at home and abroad, and the Korea Electric Power Research Institute selected it as a "secondary battery for the next-generation ESS (Energy Storage System)" and research for commercialization is underway from 2017.

Meanwhile, manganese-based cathode materials, vanadium-based cathode materials, and Prussian blue anode materials are being researched and developed as anode materials for aqueous zinc secondary batteries. The MnO ₂ -based manganese-based cathode material, which has been extensively studied, has problems such as a decrease in capacity during continuous electrochemical reactions and a phenomenon in which Mn is eluted. Therefore, there is a need for sufficient research on cathode materials.

Korean Registered Patent No. 10-2145775 (registration date 2020.08.12)

An object of the present invention is to solve the above problems, to provide a cathode active material for a zinc ion secondary battery that can be easily and simply prepared using a sol-gel synthesis method, a zinc ion secondary battery including the same, and a manufacturing method thereof. .

In addition, by applying a cathode active material containing sodium vanadate, a cathode active material for a zinc ion secondary battery having a high specific capacity (battery capacity per unit weight (mAh/g)) and excellent performance, a zinc ion secondary battery including the same And to provide a manufacturing method thereof.

According to one aspect of the present invention, a positive electrode active material for a zinc ion secondary battery represented by Chemical Formula 1 is provided.

[Formula 1]

Na _x V _y O _z (0<x≤2, 1≤y≤6, 1≤z≤15)

Also, in Chemical Formula 1, x may be 1, y may be 1, and z may be 3.

According to another aspect of the present invention, a positive electrode including a positive electrode active material for a zinc ion secondary battery represented by Formula 1 below; cathode; And an aqueous electrolyte; there is provided a zinc ion secondary battery comprising a.

[Formula 1]

Na _x V _y O _z (0<x≤2, 1≤y≤6, 1≤z≤15)

According to another aspect of the present invention, (a) preparing a precursor solution by stirring a mixed solution containing a vanadium precursor, a sodium precursor, an organic acid and a solvent; (b) preparing a gel precursor by first heat-treating the precursor solution; and (c) preparing a cathode active material represented by Chemical Formula 1 by subjecting the gel precursor to secondary heat treatment.

[Formula 1]

Na _x V _y O _z (0<x≤2, 1≤y≤6, 1≤z≤15)

In addition, the vanadium precursor may include at least one selected from the group consisting of ammonium metavanadate (NH ₄ VO ₃ ), vanadium pentoxide (V ₂ O ₅ ), and vanadium sulfate (VSO ₄ ) or hydrates thereof.

In addition, the sodium precursor is sodium hydroxide (NaOH), sodium carbonate (Na ₂ CO ₃ ), sodium chloride (NaCl), sodium sulfate (Na ₂ SO ₄ ), sodium acetate (CH ₃ COONa) and sodium citrate (Na ₂ HC ₆ H ₅ O ₇ ) may include one or more selected from the group consisting of.

In addition, the organic acid is citric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid acid), suberic acid, azelaic acid, and sebacic acid.

In addition, the solvent may include at least one selected from the group consisting of water, ethanol, methanol, propanol, isopropanol, dichlorobenzene, and methylene chloride.

In addition, the step (a) may be performed at a temperature of 30 to 100 ℃.

In addition, in step (a), the vanadium ion of the vanadium precursor may become a tetravalent vanadium ion (V ⁴⁺ ).

In addition, the first heat treatment of step (b) may be performed at a temperature of 50 to 300 ℃.

In addition, the precursor solution may be burned by the first heat treatment in step (b).

In addition, the secondary heat treatment of step (c) may be performed at a temperature of 300 to 600 ° C, so that the gel precursor may be calcined.

In addition, the secondary heat treatment of step (c) may be performed for 1 to 5 hours.

Also, in Chemical Formula 1, x may be 1, y may be 1, and z may be 3.

According to another aspect of the present invention, (a) preparing a positive electrode including a positive electrode active material for a zinc ion secondary battery represented by Formula 1 below; and (b) preparing a zinc ion secondary battery using the positive electrode, the negative electrode, and the aqueous electrolyte.

[Formula 1]

Na _x V _y O _z (0<x≤2, 1≤y≤6, 1≤z≤15)

The cathode active material for a zinc ion secondary battery of the present invention, a zinc ion secondary battery including the same, and a manufacturing method thereof can easily and simply prepare the cathode active material using a sol-gel synthesis method.

In addition, the present invention has effects of high specific capacity (battery capacity per unit weight (mAh/g)) and excellent performance by applying a cathode active material containing sodium vanadate.

Since these drawings are for reference in explaining exemplary embodiments of the present invention, the technical spirit of the present invention should not be construed as being limited to the accompanying drawings.
1 is a flowchart of a manufacturing method according to the present invention.
2 is an XRD analysis result of the cathode active material according to the present invention.
3 is a charge/discharge characteristic curve of a battery according to Device Example 1 in an aging stage.
4 is a charge/discharge characteristic curve of a battery according to Device Example 1;
5 is a lifespan characteristic curve of a battery according to Device Example 1;
6 is a graph showing coulombic efficiency characteristics of a battery according to Device Example 1;

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

However, the following description is not intended to limit the present invention to specific embodiments, and in describing the present invention, if it is determined that the detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted. .

Terms used herein are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, operation, component, or combination thereof described in the specification, but one or more other features or It should be understood that the presence or addition of numbers, steps, operations, components, or combinations thereof is not precluded.

Also, terms including ordinal numbers such as first and second to be used below may be used to describe various components, but the components are not limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention.

In addition, when a component is referred to as being “formed” or “layered” on another component, it may be formed or laminated directly on the front or one side of the surface of the other component, but intermediate It should be understood that other components may be further present.

Hereinafter, the cathode active material for a zinc ion secondary battery of the present invention and a zinc ion secondary battery including the same will be described in detail. However, this is presented as an example, and the present invention is not limited thereby, and the present invention is only defined by the scope of the claims to be described later.

The present invention provides a cathode active material for a zinc ion secondary battery represented by Formula 1 below.

[Formula 1]

Na _x V _y O _z (0<x≤2, 1≤y≤6, 1≤z≤15)

In Formula 1, x may be 1, y may be 1, and z may be 3.

In addition, the present invention is a positive electrode including a positive electrode active material for a zinc ion secondary battery represented by the following formula (1); cathode; And an aqueous electrolyte; it provides a zinc ion secondary battery comprising a.

[Formula 1]

Na _x V _y O _z (0<x≤2, 1≤y≤6, 1≤z≤15)

The positive electrode may further include a conductive material and a binder.

The conductive material may include at least one selected from the group consisting of carbon black, acetylene black, ketjen black, carbon fiber, carbon nanotube, and graphene.

The binder is polyethyleneoxide, polyethyleneglycol, polyacrylonitrile, polyvinylchloride, polymethylmethacrylate, polypropyleneoxide, polydimethylsiloxane ( polydimethylsiloxane), polyvinylidene fluoride, polyvinylidene carbonate, and polyvinyl pyrrolidinone.

The anode may include zinc as an anode active material.

The aqueous electrolyte may include water, a metal salt including zinc, and a grime-based organic solvent.

The metal salt is at least one selected from the group consisting of zinc sulfate (ZnSO ₄ ), zinc nitrate (Zn(NO ₃ ) ₂ ), zinc chloride (ZnCl ₂ ) and zinc triflate (Zn(CF ₃ SO ₃ ) ₂ ). can include

The grime-based organic solvent contains at least one selected from the group consisting of tetraethylene glycol dimethyl ether (TEGDME), triethylene glycol dimethyl ether (Triglyme), diethylene glycol dimethyl ether (Diglyme) and ethylene glycol dimethyl ether (glyme) can do.

The zinc ion secondary battery may further include a separator.

The separation membrane may include at least one selected from the group consisting of filter paper, glass fiber, polyolefin polymer membrane, polymer-SiO ₂ organic/inorganic membrane, and hydrophilic polymer material membrane.

1 is a flowchart of a method for manufacturing a cathode active material for a zinc ion secondary battery according to the present invention. Hereinafter, with reference to FIG. 1, a manufacturing method of a cathode active material for a zinc ion secondary battery and a manufacturing method of a zinc ion secondary battery including the same will be described in detail.

First, a precursor solution is prepared by stirring a mixed solution including a vanadium precursor, a sodium precursor, an organic acid, and a solvent (step a).

The vanadium precursor may include at least one selected from ammonium metavanadate (NH ₄ VO ₃ ), vanadium pentoxide (V ₂ O ₅ ) and vanadium sulfate (VSO ₄ ) or a hydrate thereof, preferably ammonium metavana date (NH ₄ VO ₃ ).

In addition, the sodium precursor is sodium hydroxide (NaOH), sodium carbonate (Na ₂ CO ₃ ), sodium chloride (NaCl), sodium sulfate (Na ₂ SO ₄ ), sodium acetate (CH ₃ COONa) and sodium citrate (Na ₂ HC ₆ H ₅ O ₇ ) may include one or more selected from the group consisting of, preferably sodium hydroxide (NaOH).

The organic acid is citric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid , may include at least one selected from the group consisting of suberic acid, azelaic acid, and sebacic acid, preferably citric acid. .

The solvent may include at least one selected from the group consisting of water, ethanol, methanol, propanol, isopropanol, dichlorobenzene, and methylene chloride, and may preferably include water.

The step (a) may be performed at a temperature of 30 to 100 °C, preferably at a temperature of 60 to 80 °C.

In step (a), the vanadium ion of the vanadium precursor may become a tetravalent vanadium ion (V ⁴⁺ ).

Next, the mixture in the sol state is subjected to secondary heat treatment to prepare a gel precursor (step b).

The first heat treatment of step (b) may be performed at a temperature of 50 to 300 °C, preferably at a temperature of 100 to 200 °C.

The precursor solution may be burned by the first heat treatment in step (b).

Finally, a positive electrode active material for a zinc ion secondary battery represented by Chemical Formula 1 is prepared by subjecting the gel precursor to a third heat treatment (step c).

The secondary heat treatment of step (c) may be performed at a temperature of 300 to 600 ° C, so that the gel precursor may be calcined, preferably at a temperature of 350 to 550 ° C.

The secondary heat treatment of step (c) may be performed for 1 to 5 hours, preferably for 2 to 4 hours.

[Formula 1]

Na _x V _y O _z (0<x≤2, 1≤y≤6, 1≤z≤15)

In Formula 1, x may be 1, y may be 1, and z may be 3.

In addition, the present invention comprises the steps of (a) preparing a positive electrode including a positive electrode active material for a zinc ion secondary battery represented by Formula 1; and (b) preparing a zinc ion secondary battery using the positive electrode, the negative electrode, and the aqueous electrolyte.

[Formula 1]

Na _x V _y O _z (0<x≤2, 1≤y≤6, 1≤z≤15)

[Example]

Hereinafter, a preferred embodiment of the present invention will be described. However, this is for illustrative purposes and the scope of the present invention is not limited thereby.

[Cathode active material for zinc ion secondary battery]

Example 1: Sodium vanadate cathode active material (NaVO ₃ )

A mixed solution was prepared by dissolving ammonium metavanadate (NH ₄ VO ₃ ), citric acid, and sodium hydroxide (NaOH) in distilled water at a molar ratio of 1: 0.75: 1, and the mixed solution was heated at 60 ° C until it turned blue. A mixture in a sol state was prepared by uniform mixing in a glass container with a lid. Subsequently, the lid of the container was opened so that water evaporated, and the mixture in a sol state was heated to 100° C. or higher and burned to prepare a gel precursor. Next, the gel precursor was calcined at 500° C. for 3 hours to prepare a sodium vanadate cathode active material (NaVO ₃ ) for a zinc ion secondary battery.

[Zinc ion secondary battery]

Device Example 1: Sodium vanadate cathode active material (NaVO ₃ ) containing cells

80 wt% of sodium vanadate cathode active material (NaVO ₃ ) for a zinc ion secondary battery according to Example 1, 10 wt% of polyvinylidene fluoride (PVDF) as a binder, 8 as a weight ratio of Super-P and MWCNT as a conductive material : After mixing at 2, 10 wt% was added and mixed to prepare a slurry. The slurry was coated on SUS foil, and vacuum dried at 110 °C for 12 hours to prepare a positive electrode, and a 1 cm ² zinc foil was prepared as a negative electrode.

A zinc ion secondary battery was manufactured using the positive electrode, the negative electrode, separator filter paper (100 μm filter paper), and an aqueous electrolyte (3M ZnSO ₄ + 0.5 wt% TEGDME in distilled water).

[Test Example]

Test Example 1: Analysis of characteristics of zinc ion secondary battery

2 is an XRD analysis result of the cathode active material (Example 1) according to the present invention.

Referring to FIG. 2 , it was confirmed that the vanadium compound according to Example 1 prepared from ammonium vanadate, citric acid, and sodium hydroxide was consistent with NaVO ₃ of the reported XRD pattern (JCPDS # 32-1198).

Test Example 2: Analysis of characteristics of zinc ion secondary battery

3 is a charge/discharge characteristic curve (0.5 C charge and discharge) of a battery according to Device Example 1 in an aging stage. 4 is a charge/discharge characteristic curve (0.5C charge and discharge) of a battery according to Device Example 1, FIG. 5 is a lifespan characteristic curve (1C charge/discharge) of a battery according to Device Example 1, and FIG. It is a graph showing the coulombic efficiency characteristics (1C charge/discharge) of the battery according to Device Example 1.

Referring to FIG. 3, sodium vanadate (NaVO ₃ ) used as a cathode active material is made of tetravalent vanadium and undergoes an aging process, which is a process of oxidizing all of them by an initial charging reaction, and charging of the battery according to this initial aging Discharge curves are plotted. As a result, an initial discharge capacity of about 250mAh/g was obtained at a current density of 0.5C.

Referring also to FIG. 4, a battery using a positive electrode and a zinc metal negative electrode prepared by applying sodium vanadate (NaVO ₃ ) as a positive electrode active material and an aqueous electrolyte in which (3M ZnSO ₄ + 0.5% TEGDME) is dissolved (Device Example 1) are the charge and discharge curves at 0.5C current density. As a cathode material for a zinc ion secondary battery, the sodium vanadate cathode material was able to obtain a high specific capacity value of 250mAh/g or more at a current density of 0.5C.

In addition, referring to FIG. 5, when looking at the life characteristics of repeated charging and discharging at a current density of 1C of a zinc ion secondary battery (device example 1) to which the sodium vanadate cathode material is applied, the sodium vanadate cathode material is a zinc ion secondary battery As a cathode material of , it was confirmed that the reversibility was excellent and the capacity was maintained without a decrease in capacity for 100 cycles, and the lifespan characteristics were excellent.

Referring also to FIG. 6, it is a graph of coulombic efficiency showing the ratio of discharge capacity to charge at 1C current density. Although the coulombic efficiency was lower than 100 within the initial 10 cycles, as the cycle progressed, the coulombic efficiency showed a value near 100, so it was confirmed that all the charged capacity was discharged.

Therefore, the present invention applies a sodium vanadate cathode active material (NaVO ₃ ) prepared by a simple sol-gel synthesis method to a zinc ion secondary battery, so that the zinc ion secondary battery has high specific capacity, stable cycle characteristics, and excellent charge and discharge performance It was found that the

The scope of the present invention is indicated by the following claims rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be construed as being included in the scope of the present invention. do.

Claims (16)

A cathode active material for a zinc ion secondary battery represented by Formula 1 below.
[Formula 1]
Na _x V _y O _z (0<x≤2, 1≤y≤6, 1≤z≤15) According to claim 1,
In Formula 1,
A cathode active material for a zinc ion secondary battery, characterized in that x is 1, y is 1, and z is 3. A positive electrode including a positive electrode active material for a zinc ion secondary battery represented by Formula 1 below;
cathode; and
water-based electrolyte;
A zinc ion secondary battery comprising:
[Formula 1]
Na _x V _y O _z (0<x≤2, 1≤y≤6, 1≤z≤15) (a) preparing a precursor solution by stirring a mixed solution containing a vanadium precursor, a sodium precursor, an organic acid and a solvent;
(b) preparing a gel precursor by first heat-treating the precursor solution; and
(c) preparing a positive electrode active material represented by Formula 1 by subjecting the gel precursor to a second heat treatment;
Method for producing a cathode active material for a zinc ion secondary battery comprising:
[Formula 1]
Na _x V _y O _z (0<x≤2, 1≤y≤6, 1≤z≤15) According to claim 4,
A cathode for a zinc ion secondary battery, characterized in that the vanadium precursor contains at least one selected from ammonium metavanadate (NH ₄ VO ₃ ), vanadium pentoxide (V ₂ O ₅ ) and vanadium sulfate (VSO ₄ ) or a hydrate thereof Methods for manufacturing active materials. According to claim 4,
The sodium precursor is sodium hydroxide (NaOH), sodium carbonate (Na ₂ CO ₃ ), sodium chloride (NaCl), sodium sulfate (Na ₂ SO ₄ ), sodium acetate (CH ₃ COONa) and sodium citrate (Na ₂ HC ₆ H ₅ O ₇ ) Method for producing a positive electrode active material for a zinc ion secondary battery, characterized in that it comprises at least one selected from the group consisting of. According to claim 4,
The organic acid is citric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid , Suberic acid (suberic acid), azelaic acid (azelaic acid), and sebacic acid (sebacic acid) a manufacturing method of a positive electrode active material for a zinc ion secondary battery characterized in that it comprises at least one member selected from the group consisting of. According to claim 4,
Method for producing a cathode active material for a zinc ion secondary battery, characterized in that the solvent comprises at least one selected from the group consisting of water, ethanol, methanol, propanol, isopropanol, dichlorobenzene and methylene chloride. According to claim 4,
Method for producing a cathode active material for a zinc ion secondary battery, characterized in that the step (a) is carried out at a temperature of 30 to 100 ℃. According to claim 4,
In step (a), the vanadium ion of the vanadium precursor is a tetravalent vanadium ion (V ⁴⁺ ) Manufacturing method of a positive electrode active material for a zinc ion secondary battery, characterized in that. According to claim 4,
The method for producing a cathode active material for a zinc ion secondary battery, characterized in that the primary heat treatment of step (b) is performed at a temperature of 50 to 300 ° C. According to claim 4,
A method for producing a cathode active material for a zinc ion secondary battery, characterized in that the precursor solution is burned by the primary heat treatment of step (b). According to claim 4,
The secondary heat treatment of step (c) is performed at a temperature of 300 to 600 ° C., characterized in that the gel precursor is calcined. According to claim 4,
A method for producing a cathode active material for a zinc ion secondary battery, characterized in that the secondary heat treatment of step (c) is performed for 1 to 5 hours. According to claim 4,
In Formula 1,
A method for producing a cathode active material for a zinc ion secondary battery, characterized in that x is 1, y is 1, and z is 3. (a) preparing a cathode including a cathode active material for a zinc ion secondary battery represented by Chemical Formula 1; and
(b) preparing a zinc ion secondary battery using the anode, cathode, and aqueous electrolyte;
A method for manufacturing a zinc ion secondary battery comprising:
[Formula 1]
Na _x V _y O _z (0<x≤2, 1≤y≤6, 1≤z≤15)

Images