KR102171532B1 - Eutectic liquid metal-air batteries comprising liquid metal electrode and method of preparation thereof - Google Patents

Abstract

The present invention relates to a eutectic liquid metal air battery including a liquid metal cathode and a method for manufacturing the same, wherein the eutectic liquid metal air battery is inserted into a cathode current collector and is a liquid at room temperature. A liquid metal cathode comprising a liquid metal cathode, comprising a polymer fiber coated with a gel electrolyte and having elasticity, the elastic electrolyte layer surrounding the liquid metal cathode, and at least part of the elastic electrolyte layer contacting, and at least part of the surface It is characterized in that it comprises a carbon fiber anode including a carbon fiber on which the catalyst is formed.

Description

Eutectic liquid metal air battery including liquid metal cathode and its manufacturing method {EUTECTIC LIQUID METAL-AIR BATTERIES COMPRISING LIQUID METAL ELECTRODE AND METHOD OF PREPARATION THEREOF}

The present invention relates to a eutectic liquid metal air battery including a liquid metal cathode and a method of manufacturing the same. In more detail, it relates to a eutectic liquid metal air battery using a gallium/indium eutectic liquid metal as a cathode and including an elastic electrolyte layer on which a stretchable material is supported, and a method of manufacturing the same.

Recently, electronic devices have been developed in the form of wearable devices, soft robotics, and human body attachment types, using materials having excellent elasticity. Materials having excellent elasticity can be manufactured in the form of clothing, and can be well attached to objects having a curved surface, such as human skin and organs.

In particular, the demand for flexible and elastic fiber-type power devices is increasing. In order to meet the requirements in the wearable electronic device market, products of wearable power devices such as fibrous solar cells/batteries and power fibers having a micro-cable structure are attracting much attention. In addition, even in the case of the battery type, the shape of the device into textile is superior to the shape that only has flexibility characteristics, such as the device on textile. It is receiving a lot of attention. However, batteries including solid metal electrodes that are currently commercially available have very limited flexibility and elasticity due to inherent limitations of materials.

In order to overcome the above problems, most of the metal electrodes are in the form of a thin wire/sheet or have a spring-shaped structure. Nevertheless, due to the characteristics of solid metals, both flexibility and elasticity have not reached the level of practical use. In addition, a method of arranging the unit battery cells with a pair of elastic substrates therebetween has been proposed, but there is a problem in that the energy density is lowered because the unit battery cells are arranged at intervals in an island shape.

As an alternative to this, a method of securing flexibility and elasticity and generating electricity by friction by coating an electrode layer on the surface of a substrate and manufacturing a plurality of substrates to have a fabric structure has been proposed. However, electricity generated by frictional force has a low current value, and it is difficult to produce constant power due to a change in voltage value according to frictional strength.

Therefore, in order to solve various problems including the above problems, the present invention uses a eutectic liquid metal mixture that may exist in a liquid state at room temperature as a negative electrode active material, and the elastic electrolyte layer coated with a gel electrolyte having excellent elasticity An object of the present invention is to provide a eutectic liquid metal air battery in which the anode active material is injected into the interior and coated with a carbon fiber anode on which a metal catalyst is formed.

In addition, the present invention is to improve the mechanical and electrical properties of the eutectic liquid metal pneumatic by including the gallium / indium eutectic mixture as a negative electrode active material, it is possible to control the generated current and to improve the bending deformation and elasticity. do.

However, these problems are exemplary, and the scope of the present invention is not limited thereby.

According to one aspect of the present invention for solving the above problem, a negative electrode current collector is inserted, the liquid metal cathode including a eutectic liquid metal negative electrode active material liquid at room temperature; An elastic electrolyte layer coated with a gel electrolyte and comprising polymer fibers having elasticity, and surrounding the liquid metal cathode; And there is provided a eutectic liquid metal air battery comprising a carbon fiber anode including carbon fibers in which at least a portion of the elastic electrolyte layer and the metal catalyst are formed in contact with the elastic electrolyte layer.

In addition, according to an embodiment of the present invention, the eutectic liquid metal anode active material may include gallium (Ga) and indium (In).

In addition, according to an embodiment of the present invention, the eutectic liquid metal anode active material may include 74.8 parts by weight to 92.8 parts by weight of gallium and 7.2 parts by weight to 25.2 parts by weight of indium.

In addition, according to an embodiment of the present invention, the polymer fiber may include nylon.

Further, according to an embodiment of the present invention, the metal catalyst may be at least one of platinum (Pt), palladium (Pd), and silver (Ag).

Further, according to an embodiment of the present invention, the current density may be controlled according to the injection amount of the eutectic liquid metal anode active material.

Further, according to an embodiment of the present invention, the eutectic liquid metal air battery may have a current density ranging from 1000 μW/cm ^-2 to 1200 μW/cm ^-2 .

In addition, according to an embodiment of the present invention, the eutectic liquid metal air battery may expand and contract up to 90% to 110% of the initial length.

In addition, according to an embodiment of the present invention, the elastic electrolyte layer may have a cylindrical structure.

And, according to another aspect of the present invention for solving the above problems, (a) preparing a eutectic liquid metal negative electrode active material liquid at room temperature; (b) supporting a polymer fiber having elasticity in a solution containing a gel electrolyte precursor and polymerizing the gel electrolyte precursor; (c) forming an elastic electrolyte layer by rolling the polymer fiber; And (d) forming a carbon fiber anode such that at least a portion of the elastic electrolyte layer is in contact, and forming a liquid metal anode by disposing the eutectic liquid metal anode active material and a cathode current collector inside the elastic electrolyte layer. A method of manufacturing a eutectic liquid metal air battery is provided.

In addition, according to an embodiment of the present invention, the eutectic liquid metal anode active material may include gallium (Ga) and indium (In).

In addition, according to an embodiment of the present invention, the carbon fiber anode includes carbon fibers in which a metal catalyst is formed on at least a part of a surface, and the metal catalyst may be formed on the carbon fiber by an electrochemical deposition method.

According to an embodiment of the present invention made as described above, a eutectic liquid metal mixture, which may exist in a liquid state at room temperature, is used as a negative electrode active material, and the negative electrode active material is placed inside an elastic electrolyte layer coated with a gel electrolyte having excellent elasticity. Injecting, it is possible to provide a eutectic liquid metal air battery coated with a carbon fiber anode on which a metal catalyst is formed.

In addition, the present invention includes a gallium/indium eutectic mixture as a negative electrode active material, so that the generated current can be controlled, and the properties for bending deformation and elasticity are excellent, thereby improving the mechanical and electrical properties of the eutectic liquid metal pneumatic material.

Of course, the scope of the present invention is not limited by these effects.

1 is a schematic diagram showing the structure of a eutectic liquid metal air battery according to an embodiment of the present invention.
2 is a flow chart showing a method of manufacturing a eutectic liquid metal air battery according to an embodiment of the present invention.
3 is a phase equilibrium diagram of a gallium-indium metal according to an embodiment of the present invention.
4 is a scanning electron microscope (SEM) photograph showing a carbon fiber deposited with a platinum catalyst according to an embodiment of the present invention.
5 is a schematic diagram showing a method of manufacturing an EGILM air battery in the form of a cable according to an embodiment of the present invention.
6 is a schematic diagram showing the structure of a cable-type EGILM air battery according to an embodiment of the present invention.
7 is a photograph showing the test results of corrosion resistance of a common gallium/indium mixture for an aqueous alkali solution according to an experimental example of the present invention.
8 is a photograph showing a result of evaluating the flexibility of a gallium/indium eutectic mixture according to an experimental example of the present invention.
9 is a photograph showing the tensile property evaluation result according to the content of the polymerization initiator in the aqueous gel electrolyte according to an experimental example of the present invention.
10 is a schematic diagram showing an experiment of an operation mechanism of an open EGILM air battery according to an experimental example of the present invention.
11 is an X-ray diffraction (XRD) analysis graph, energy dispersive spectrometer (EDS) analysis showing the reaction byproduct analysis result after discharge of an open EGILM air battery according to an experimental example of the present invention This is a graph and a scanning electron microscope (SEM) picture.
12 is a graph showing the results of an experiment measuring discharge characteristics of an EGILM air battery according to an experimental example of the present invention.
13 is a graph showing discharge characteristics of an EGILM air battery according to whether carbon fiber is deposited with a platinum catalyst according to an experimental example of the present invention.
14 is a graph showing the results of a life characteristic experiment of an EGILM air battery according to an experimental example of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The detailed description of the present invention to be described later refers to the accompanying drawings, which illustrate specific embodiments in which the present invention may be practiced. These embodiments are described in detail sufficient to enable a person skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different from each other but need not be mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the present invention in relation to one embodiment. In addition, it is to be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the present invention. Accordingly, the detailed description to be described below is not intended to be taken in a limiting sense, and the scope of the present invention, if properly described, is limited only by the appended claims, along with all scopes equivalent to those claimed by the claims. In the drawings, similar reference numerals refer to the same or similar functions over several aspects, and the length, area, thickness, and the like may be exaggerated and expressed for convenience.

In the present specification, terms such as "comprise" or "have" are intended to designate that the described features, numbers, steps, actions, components, parts, or combinations thereof exist, but one or more other features or numbers, It is to be understood that the presence or addition of steps, actions, components, parts, or combinations thereof, does not preclude the possibility of preliminary exclusion.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to enable those of ordinary skill in the art to easily implement the present invention.

The present invention relates to a eutectic liquid metal air battery having elasticity and excellent mechanical and electrical stability, including an electrolyte layer using a polymer fiber having elasticity and comprising a eutectic liquid metal present in a liquid state at room temperature as a negative electrode active material.

1 is a schematic diagram showing the configuration of a eutectic liquid metal air battery 10 according to an embodiment of the present invention.

Referring to FIG. 1, the eutectic liquid metal air battery 10 of the present invention may include a liquid metal cathode 100, an elastic electrolyte layer 200, and a carbon fiber anode 300.

The liquid metal cathode 100 may include a eutectic liquid metal anode active material 120 into which the anode current collector 110 is inserted and includes at least one metal that is liquid at room temperature.

Since the conventional metal-air battery uses a solid metal as a negative electrode, the flexibility and elasticity of the air battery are limited. In order to solve this problem, a metal wire or a spring-shaped metal was manufactured, but there is a disadvantage in that the limit values for flexibility and elasticity are low nonetheless. In addition, conventional metal-based batteries have a problem in that dendrite is formed at the metal anode.

Accordingly, in order to solve the above problems, the present invention is characterized in that the liquid metal cathode 100 includes a eutectic liquid metal anode active material 120 that is liquid at room temperature. The eutectic liquid metal anode active material 120, which is liquid at room temperature, can improve the flexibility and elasticity of the eutectic liquid metal air battery 10, and can suppress the formation of dendrite in an electrochemical environment. In particular, when a deformation caused by an external force occurs, the non-contact area with the electrolyte can be removed by the flow of liquid, thereby effectively maintaining the performance of the battery.

According to an embodiment, the eutectic liquid metal anode active material 120 may include gallium (Ga) and indium (In). Gallium (Ga) has good reactivity with the hydroxyl group (-OH) of alkaline electrolytes used in liquid metal air batteries. Thus, when indium is added, there is an effect of suppressing corrosion of gallium from the alkaline electrolyte through a substitution reaction between indium ions (In ³⁺ ) and gallium. By using a eutectic liquid metal of gallium/indium as the negative electrode active material 120, reactivity and stability of the negative electrode may be improved.

When the gallium/indium compound is mixed in a specific amount, it may exist in a liquid state at room temperature. The liquid gallium/indium compound can be prepared simply by melting the two metals and mixing them while adjusting the content. As described above, the liquid gallium/indium eutectic liquid metal anode active material 120 has high reactivity by gallium and stability by indium, and is liquid at room temperature, so the eutectic liquid metal air battery 10 has flexibility and elasticity. Can be given. At this time, as an example, the eutectic liquid metal anode active material 120 may contain 74.8 parts by weight of gallium to 92.8 parts by weight of indium and 7.2 parts by weight of indium to 25.2 parts by weight, preferably 90 parts by weight of gallium, and 10 parts by weight of indium. I can.

In addition, the liquid metal cathode 100 may include an anode current collector 110. The negative electrode current collector 110 is inserted into the eutectic liquid metal negative electrode active material 120, and preferably may be inserted into the center of the negative electrode active material 120. It is electrically connected to the external carbon fiber anode 300 through the anode current collector 110 to serve as a battery. The negative electrode current collector 110 may include nickel (Ni) or the like.

The elastic electrolyte layer 200 is disposed between the liquid metal cathode 100 and the carbon fiber anode 300 of the eutectic liquid metal air battery 10 to transmit ions formed during discharge of the battery. The elastic electrolyte layer 200 may include a polymer fiber 210 having elasticity and a gel electrolyte 220 coated on the polymer fiber 210.

The gel electrolyte 220 may include, for example, an aqueous gel electrolyte to impart flexibility and elasticity of the eutectic liquid metal air battery 10. In addition, since it is coated on the polymer fiber 210 having elasticity, flexibility due to the polymer fiber 210 can be maximized. At this time, according to an embodiment, the polymer fiber 210 may include nylon, and the electrolyte 220 may include polyacrylamide (PAA).

The elastic electrolyte layer 200 may have a structure surrounding the liquid metal cathode 100. Preferably, it may have a cylindrical structure. Since the polymer fiber 210 is formed by rolling, the central portion may have a hollow cylindrical structure. The elastic electrolyte layer 200 of this type can efficiently increase the contact area between the liquid metal cathode 100 and the carbon fiber anode 300 formed inside and outside, and the eutectic liquid metal air battery having a fibrous structure. (10) to be able to manufacture. Of course, within the scope of the purpose of increasing the contact area of the liquid metal cathode 100 and increasing the contact area of the carbon island-gyu anode 300, other structures other than the cylindrical structure may be employed.

The liquid metal cathode 100 may be disposed inside the elastic electrolyte layer 200, and the liquid metal cathode 100 is injected into the elastic electrolyte layer 200, or the liquid metal cathode 100 is formed in the elastic electrolyte layer ( 200) can use this wrapping method.

The carbon fiber anode 300 may include a carbon fiber 310 having a metal catalyst 320 formed on at least a portion of the surface. The carbon fiber 310 has flexibility and elasticity together with the liquid metal cathode 100 and the elastic electrolyte layer 200. In addition, by forming the metal catalyst 320 on at least a portion of the surface, it is possible to improve the electrochemical performance of the air battery. The metal catalyst 320 may be made of platinum (Pt), palladium (Pd), silver (Ag), or the like, but various materials may be used within the purpose of improving the reactivity of the carbon fiber anode 300.

At least a part of the carbon fiber anode 300 may come into contact with the elastic electrolyte layer 200. FIG. 1 shows a form in which the elastic electrolyte layer 200 is disposed inside the carbon fiber anode 300 while the carbon fiber anode 300 surrounds the elastic electrolyte layer 200.

According to an embodiment, in the eutectic liquid metal air battery 10, the liquid metal cathode 100 is injected into the elastic electrolyte layer 200, and the carbon fiber anode 300 may be coated on the outside. In the elastic electrolyte layer 200 having a cylindrical structure, an empty space is formed inside the central portion to accommodate a negative electrode material. Accordingly, a liquid metal cathode 100 including the eutectic liquid metal anode active material 120 is injected to form a negative electrode of the battery. Then, a positive electrode of the battery is formed by coating the carbon fiber positive electrode 300 on the outside of the cylindrical structure. Since the elastic electrolyte layer 200 has a cylindrical structure, the eutectic liquid metal air battery 10 may be manufactured in a fibrous structure, and may have flexibility against stretching or bending deformation in the longitudinal direction.

Meanwhile, the current density of the eutectic liquid metal air battery 10 may be adjusted according to the injection amount of the eutectic liquid metal anode active material 120. The eutectic liquid metal air battery 10 needs to be manufactured by varying the current density according to the type of power device used. Accordingly, the eutectic liquid metal-air battery 10 of the present invention can control the performance of the battery by controlling the injection amount of the eutectic liquid metal anode active material 120 included in the negative electrode. As an example, the eutectic liquid metal air battery 10 may have a current density in the range of 1000 μW/cm ^-2 to 1200 μW/cm ^-2 .

In addition, when the eutectic liquid metal air battery 10 is discharged, the discharged eutectic liquid metal anode active material 120 is removed from the inside of the elastic electrolyte layer 100, and the eutectic liquid metal anode active material 120 is not discharged. can do. When completely discharged using the eutectic liquid metal air battery 10 as a power device, all gallium (Ga) of the eutectic liquid metal anode active material 120 is exhausted. At this time, the battery can be easily regenerated by replacing the eutectic liquid metal anode active material 120 without performing a charging step of converting gallium ions (Ga ³⁺ ) into gallium (Ga). The eutectic liquid metal anode active material 120 may be removed on at least a portion of the surface of the eutectic liquid metal air battery 10 and an injection hole, which is a passage through which the eutectic liquid metal anode active material 120 can be removed, may be further formed.

In addition, according to an embodiment of the present invention, the eutectic liquid metal air battery 10 may expand and contract up to 90% to 110% of the initial length. The expansion and contraction of the eutectic liquid metal air battery 10 may be understood to include not only extending and contracting in one direction, but also extending and contracting in various directions such as bending and bending. As described above, the eutectic liquid metal air battery 10 including the liquid eutectic liquid metal anode active material 120, the elastic electrolyte layer 200 including polymer fibers, and the carbon fiber anode 300 has excellent flexibility and elasticity. Have. Flexibility and elasticity are superior due to the characteristics of the battery material itself than the case of manufacturing a wire or a spring using a conventional metal negative electrode. In addition, since the liquid metal cathode 100 is included, it is possible to solve the problem of dendrite formation occurring in the metal anode battery.

Hereinafter, a method of manufacturing the eutectic liquid metal air battery 10 according to an embodiment of the present invention will be described with reference to FIG. 2.

2 is a flow chart showing a method of manufacturing a eutectic liquid metal air battery 10 according to an embodiment of the present invention.

Referring to FIG. 2, the method of manufacturing the eutectic liquid metal air battery 10 of the present invention includes the steps of: (a) preparing a eutectic liquid metal negative electrode active material 120 that is liquid at room temperature (S100). , (b) supporting a polymer fiber 210 having elasticity in a solution containing a gel electrolyte precursor, and polymerizing the gel electrolyte precursor (S200), (c) rolling the polymer fiber to elasticity Steps of forming the electrolyte layer 200 (S300) and (d) forming a carbon fiber anode 300 so that at least a part of the elastic electrolyte layer 200 is in contact, and a eutectic liquid metal inside the elastic electrolyte layer 200 A step (S400) of forming the liquid metal cathode 100 by disposing the anode active material 120 and the anode current collector 110 may be included.

First, (a) a eutectic liquid metal negative electrode active material 120 that is liquid at room temperature is prepared (S100). As described above, the eutectic liquid metal anode active material 120 can be prepared by a simple method by melting and mixing two kinds of metals that are liquid at room temperature. At this time, as an example, the eutectic liquid metal anode active material 120 may contain gallium (Ga) and indium (In), and the eutectic liquid metal anode active material 120 in a liquid state at room temperature may be prepared by adjusting an appropriate content range. I can. Preferably, the eutectic liquid metal anode active material 120 may contain 74.8 parts by weight of gallium to 92.8 parts by weight of indium, 7.2 parts by weight to 25.2 parts by weight of indium, and preferably 90 parts by weight of gallium and 10 parts by weight of indium. have.

Next, (b) a polymer fiber 210 having elasticity is supported in a solution containing a gel electrolyte precursor, and the gel electrolyte precursor is polymerized (S200). Before the gel electrolyte precursor is completely cured to form the gel electrolyte 220, the polymer fibers 210 may be supported, so that the gel electrolyte 220 may be coated on the polymer fibers 210. A crosslinking agent is first added to the solution containing the gel electrolyte precursor, and the polymer fibers 210 are supported before the polymerization reaction of the precursor proceeds. Thereafter, the gel electrolyte precursor is polymerized for a predetermined period of time to coat the gel electrolyte 220 on the polymer fiber 210.

At this time, the properties of the elastic electrolyte layer 200 may be controlled according to the content of the crosslinking agent added during the manufacture of the gel electrolyte 220. As the content of the crosslinking agent increases, the length of the polymer chain in the gel electrolyte 220 decreases, so the ionic conductivity may increase. However, it is necessary to add only the necessary amount because the elastic recovery power may be lowered if it is added in an excessive amount. According to an embodiment of the present invention, the amount of the added crosslinking agent may be 3.0 mL to 4.0 mL, preferably 3.5 mL.

Then, (c) the polymer fiber 210 coated with the gel electrolyte 220 is rolled to form the elastic electrolyte layer 200 (S300). As described above, the eutectic liquid metal air battery 10 of the present invention may have a fibrous structure including the elastic electrolyte layer 200 having a cylindrical structure. The elastic electrolyte layer 200 may form an empty space therein to accommodate a negative electrode material.

Finally, (d) a eutectic liquid metal anode active material 120 in which the carbon fiber anode 300 is coated on the outside of the elastic electrolyte layer 200, and the anode current collector 110 is inserted into the elastic electrolyte layer 200. ) Is injected to form the liquid metal cathode 100 (S400). Based on the elastic electrolyte layer 200, a liquid metal cathode 100 is formed inside and a carbon fiber anode 300 is formed outside, and a contact surface area may be increased by a cylindrical structure.

Meanwhile, the carbon fiber anode 300 may include a carbon fiber 310 having a metal catalyst 320 formed on at least a portion of the surface. The metal catalyst 320 may be formed on the carbon fiber 310 by an electrochemical deposition method. Since the carbon fiber anode 300 is excellent in flexibility and elasticity including the carbon fiber 310, it can be easily formed outside the elastic electrolyte layer 200 having a cylindrical structure. In this case, as an example, the carbon fiber anode 300 may be wrapped to coat the outside of the elastic electrolyte layer 200. The carbon fiber anode 300 manufactured by depositing the metal catalyst 320 may improve the electrochemical performance of the eutectic liquid metal air battery 10.

Hereinafter, examples and experimental examples for aiding understanding of the present invention will be described. However, the following Examples and Experimental Examples are only intended to aid understanding of the present invention, and the present invention is not limited to the following Examples and Experimental Examples.

Example 1: Preparation of gallium/indium eutectic liquid metal air battery

An air battery including a gallium/indium eutectic liquid metal electrode according to an embodiment of the present invention will be described with reference to FIGS. 3 to 6.

1) Preparation of gallium/indium eutectic liquid metal anode active material (EGILM)

First, a gallium/indium eutectic liquid metal anode active material is prepared to form a gallium/indium eutectic liquid metal air battery. 3 is a phase equilibrium diagram of a gallium-indium metal according to an embodiment of the present invention. In a specific content range, the gallium-indium mixture may exist in a liquid state at room temperature. As shown in FIG. 3, a mixture containing 74.8 to 92.8 parts by weight of gallium and 7.2 to 25.2 parts by weight of indium may be present in a liquid state. A gallium/indium eutectic liquid metal anode active material within the above composition range is prepared.

First, pure indium and gallium are heated to 160° C. and 40° C. for 30 minutes, respectively, and then the two liquid metals are mixed and stirred at 160° C. for 30 minutes to prepare a gallium/indium eutectic liquid metal anode active material (hereinafter “EGILM”). Prepare. At this time, in EGILM, gallium is mixed to contain 90 parts by weight and indium is 10 parts by weight.

2) Preparation of an aqueous gel electrolyte containing polyacrylamide

To prepare a polyacrylamide-based aqueous gel electrolyte used as a gel electrolyte for a eutectic liquid metal air battery.

First, 0.2 mol, 99% KOH powder is dissolved in 17.8 mL of distilled water to prepare an alkaline aqueous solution. Then, 25.95 mmol, 99% of acrylic acid and 1.82 mmol, 99.5% of N,N'-methylenebisacrylamide were mixed to prepare a gel crosslinking agent solution. Then, the aqueous alkali solution and the gel crosslinking agent solution are mixed, and the precipitate is filtered to prepare a polymerization precursor solution. Then, 3.5 mL (104.2 mmol L ^-1 ) of a K ₂ S ₂ O ₈ solution having a concentration of 0.7 mol L ^-1 as a polymerization initiator was added to the polymerization precursor solution and stirred vigorously. After a few seconds, the final solution was poured into a Petri dish to a thickness of about 1 mm, and polymerization was performed at room temperature for 10 minutes to prepare an aqueous polyacrylamide gel electrolyte.

3) Preparation of carbon fiber deposited with platinum catalyst nanoparticles

In order to manufacture a carbon fiber anode, a carbon fiber on which platinum catalyst nanoparticles are deposited is prepared.

A deposition system was prepared using carbon fiber as a working electrode, a platinum substrate as a counter electrode, and a saturated calomel electrode as a reference electrode, and electrochemical deposition was performed at room temperature. The platinum catalyst is in an aqueous electrolyte environment consisting of 0.5 mol L ^-1 of H ₂ SO ₄ and 1.0 mol L ^-1 of H ₂ PtCl ₂ and 10 ^-6 mol L ^-1 of polyethylene glycol, in an aqueous electrolyte environment of -3 mA cm ^-1 . As a current density, it was deposited for 2 hours through a pulse with t _on /t _off of 1s/5s.

4 is a scanning electron microscope (SEM) photograph showing a carbon fiber deposited with a platinum catalyst according to an embodiment of the present invention. Referring to FIG. 4, the conventional carbon fiber (shown in FIG. 4(a)) has a smooth surface, whereas the carbon fiber (shown in FIG. 4(b)) deposited with a platinum catalyst has a relatively rough surface. . That is, it can be seen that the platinum catalyst is well deposited on the surface of the carbon fiber.

4) Manufacture of cable type EGILM (eutectic Ga/In liquid metal) air battery

Using the gallium/indium eutectic liquid metal anode active material prepared in 1) to 3) above, an aqueous gel electrolyte, and carbon fiber deposited with a platinum catalyst, an EGILM air battery in the form of a cable is manufactured. In this embodiment, a schematic diagram showing a method of manufacturing a cable-type EGILM air battery is shown in FIG. 5.

5 is a schematic diagram showing a method of manufacturing an EGILM air battery in the form of a cable according to an embodiment of the present invention.

At this time, an elastic electrolyte layer is prepared by supporting nylon fibers with polymer fibers on an aqueous gel electrolyte. A nylon fiber having a size of 15 cm x 3.8 cm is supported in the solution before the polymerization reaction of the aqueous gel electrolyte prepared in 2) is completed. After 10 minutes, when the polymerization reaction of the gel electrolyte is completed, the gel electrolyte in which nylon fibers are inserted is wound round to prepare an elastic electrolyte layer having a hollow cylindrical structure.

Then, 55 cm of carbon fiber (8.3 mg of platinum and 444 mg of carbon fiber) coated with the platinum catalyst prepared in 3) is wrapped around the outside of the elastic electrolyte layer having a cylindrical structure to form a carbon fiber anode. Finally, 1.32 mL of EGILM is injected into the empty space inside the cylindrical elastic electrolyte layer, and a nickel plate is inserted into contact with the EGILM as a negative electrode current collector to form a liquid metal cathode. Finally, an EGILM air battery having a cable size of 12 cm in length and 8 mm in diameter is manufactured by tying both ends with a thread. The EGILM air battery manufactured by the above method is hereinafter referred to as'Example 1'.

6 is a schematic diagram showing the structure of a cable-type EGILM air battery according to an embodiment of the present invention. As shown in Figure 6, Example 1 including an EGILM liquid metal cathode, an elastic electrolyte layer immersed in polyacrylamide-based nylon fiber, and a carbon fiber anode on which a platinum catalyst is deposited, is easy to recharge the cathode, and excellent It has softness and flexibility properties.

Hereinafter, with reference to FIGS. 7 to 14, the characteristics of the EGILM negative electrode active material and aqueous gel electrolyte of Example 1 and the electrical characteristics of the cable-type EGILM air battery (Example 1) will be described.

Experimental Example 1. Evaluation of resistance of gallium/indium eutectic liquid metal anode active material to aqueous alkali solution

In order to confirm the possibility that the EGILM prepared in Example 1 could be used as an electrode of the air battery of the present invention, a corrosion resistance test for an aqueous alkali solution was performed. Corrosion resistance tests were performed for the EGILM prepared in Example 1 and 37.5 parts by weight of KOH aqueous solution of gallium, indium, aluminum and zinc metals.

7 is a photograph showing a result of an experiment on corrosion resistance of a gallium/indium co-liquid metal anode active material to an alkaline aqueous solution according to an experimental example of the present invention.

Referring to FIG. 7, it can be seen that in the case of aluminum metal, the reactivity with the KOH aqueous solution is most active, and the corrosion rate is the fastest. In the case of zinc and gallium, the reaction rate was slower than that of aluminum, and in the case of indium, a corrosion reaction hardly occurred. This means that indium has the best chemical stability for alkaline solutions. EGILM according to an embodiment of the present invention also exhibits a lower corrosion reaction rate compared to gallium. The violent corrosion reaction causes loss of the negative electrode active material and deterioration of battery performance.The eutectic liquid metal air battery according to the present invention can effectively suppress the corrosion of gallium by using EGILM containing indium as the negative electrode active material.

Experimental Example 2. Flexibility evaluation of gallium/indium eutectic liquid metal anode active material

An experiment to evaluate the flexibility of the EGILM prepared in Example 1 was performed. EGILM is coated on various types of substrates to evaluate metallicity, fluidity, and conductivity.

8 is a photograph showing a result of evaluating the flexibility of a gallium/indium eutectic liquid metal anode active material according to an experimental example of the present invention.

First, referring to (a) of FIG. 8, it can be seen the change in electrical conductivity when the EGILM formed on a paper substrate is folded and unfolded. It can be seen that the electrical conductivity of the EGILM is kept constant when the paper substrate is deformed.

And, referring to (b) of FIG. 8, it can be seen the change in electrical conductivity when the EGILM formed on the rubber substrate is increased and then recovered. It can be seen that EGILM maintains a certain level of electrical conductivity even when the rubber substrate is deformed, and has excellent resilience when restored to its initial state. This means that the EGILM of the present invention has excellent flexibility, elasticity and resilience.

Experimental Example 3: Evaluation of tensile properties of aqueous polyacrylamide gel electrolyte

The polyacrylamide aqueous gel electrolyte prepared in Example 1 may control the tensile properties of the aqueous gel electrolyte film by adjusting the content of the polymerization initiator K ₂ S ₂ O ₈ . Prepared in the same manner as in Example 1, but the polymerization initiator of K ₂ S ₂ O ₈ The content is adjusted to evaluate the tensile properties of the gel electrolyte film. An aqueous gel electrolyte film was prepared by adding 0.5 mL, 2.5 mL, 3.5 mL, 4.5 mL, and 6.5 mL of K ₂ S ₂ O ₈ as a polymerization initiator, respectively, and tensile properties and adhesion were evaluated, and the results are shown in FIG. Shown.

9 is a photograph showing the tensile property evaluation result according to the content of the polymerization initiator in the aqueous gel electrolyte according to an experimental example of the present invention.

Figure 9 (a) shows the tensile properties evaluation of the aqueous gel electrolyte to which 3.5 mL of polymerization initiator is added, and Figure 9 (b) shows the addition of 0.5 mL, 2.5 mL, 3.5 mL, 4.5 mL, and 6.5 mL of polymerization initiator, respectively. It is a photograph showing the evaluation of the adhesive strength of the prepared aqueous gel electrolyte film.

The strong adhesion between the gel electrolyte and the carbon fiber anode is an important factor in driving the air cell. As the content of the polymerization initiator is increased in the preparation of the gel electrolyte, the adhesion of the gel electrolyte is improved. In addition, the color of the gel electrolyte is also changed so that it has a gray color in a transparent state. This means that the polymer chain length became shorter as the content of the polymerization initiator increased. As the polymer chain length is shortened, the ionic conductivity increases from 0.42 Scm ^-1 to 0.45 Scm ^-1 .

In addition, referring to (c) of FIG. 9, tensile properties and resilience properties according to the content of the polymerization initiator can be seen. An aqueous gel electrolyte to which 3.5 mL of a polymerization initiator is added has an elongation of 205.36% at most. If the added polymerization initiator is more than 3.5 mL, the elastic recovery rate is 99.50% or more, but if it is more than 3.5 mL, the elastic recovery rate decreases rapidly. Therefore, the polymerization initiator added to the aqueous gel electrolyte may have the most optimal properties when added as much as 3.5 mL.

Experimental Example 4: EGILM air battery operation mechanism experiment

In order to understand the mechanism of operation of the EGILM air battery, an open EGILM air battery was manufactured and a discharge test was performed. At this time, a schematic diagram of the operation mechanism experiment of the open-type EGILM air battery is shown in FIG. 10.

10 is a schematic diagram showing an experiment of an operation mechanism of an open EGILM air battery according to an experimental example of the present invention.

First, an open-type battery was manufactured using 3 g of EGILM negative electrode and carbon fiber positive electrode in a glass beaker containing 50 mL, 37.5 parts by weight of KOH solution. The mesh-shaped nickel mesh was used for holding EGILM and as an anode current collector. The open EGILM air battery was discharged for one week by shorting the cathode and anode by connecting the cathode and anode at room temperature. The reaction by-product on the cathode side was recovered from the nickel mesh, and the reaction by-product of hair-moisture was recovered by filtering the electrolyte. At this time, the crystalline by-product was obtained by neutralizing the alkali solution using 3 mol L ^-1 of HCl solution. And, the composition of the by-product obtained after the discharge reaction was analyzed, and the results are shown in FIG. 11.

11 is an X-ray diffraction (XRD) analysis, energy dispersive spectrometer (EDS) analysis graph showing the reaction byproduct analysis result after discharge of an open EGILM air battery according to an experimental example of the present invention And a scanning electron microscope (SEM) photograph.

10 and 11, after discharging the open EGILM air battery for a week, it can be seen that three reaction by-products were generated. This is a crystal product produced by neutralization reaction of the reaction product at the cathode, the solidified material settled on the bottom of the beaker, and the alkaline electrolyte with hydrochloric acid, respectively.

First, referring to (a) of FIG. 11, the main components of each reaction by-product were confirmed through EDS analysis. First, it can be seen that the reaction product at the cathode is indium, the solidified material is indium hydroxide (In(OH) ₃ ), and the crystal product obtained from the electrolyte is gallium hydroxide (GaOOH). This means that some indium and all gallium in EGILM is used in the reaction to produce reaction by-products, and the remaining indium is solidified.

Experimental Example 5: Evaluation of electrochemical properties of EGILM air battery

Electrochemical characteristic evaluation was performed using the cable-type EGILM air battery prepared in Example 1. The EGILM air battery has a length of 12 cm and a diameter of 8 mm.

The linear polarization test of the EGILM air battery was measured at a scanning rate of 2 mV s ^-1 , and the discharge performance test was performed in a constant voltage mode at 1.2 V. And, in the "3) Preparation of carbon fiber deposited with a platinum catalyst" of Example 1, a cable-type EGILM air cell was manufactured in the same manner except that carbon fiber without a platinum catalyst was used (hereinafter, Comparative Example 1), and electrochemical property evaluation was performed.

First, a linear polarization test and a discharge performance test of the EGILM air battery of Example 1 were performed, and the results are shown in FIG. 12.

12 is a graph showing the results of an experiment measuring discharge characteristics of an EGILM air battery according to an experimental example of the present invention.

Referring to FIG. 12A, in Example 1, when the injection amount of EGILM is set to 1/4, 1/2, 3/4, 4/4, each current is 0 mA to 14.265 mA, 16.015 mA, and 16.226 mA, increased to 16.286 mA. This means that in Example 1, the discharge current can be controlled by adjusting the injection amount of the EGILM.

And, referring to (b) of FIG. 12, it can be seen that the discharge current of the first embodiment can be adjusted by the pressure applied from the outside. This is because the liquid EGILM can be easily disconnected by the flexible deformation of the battery resulting from external pressure. When the battery was disconnected by applying external pressure to a position of 1/4, 1/2, and 3/4 of the total length, the discharge current decreased from 16.859 mA to 14.235 mA, 15.954 mA, and 16.196 mA, respectively. It is almost the same level as the discharge current value shown in FIG. 12A, which represents an important characteristic of a liquid metal air battery capable of controlling the discharge current value by the amount of the electrode material. In addition, as shown in FIG. 12B, when the pressure applied to the air cell is removed, the discharge current quickly recovers to the initial current value.

And, referring to (c) of FIG. 12, it can be seen that the cable-type EGILM air battery of Example 1 has excellent flexibility and recovery. Example 1 showed bending and recovery operations in the range of a curve radius of 1 dm to 1 mm, and at this time, the discharge current curve maintained a constant shape without change. In order to confirm the flexibility of Example 1, it was confirmed that the electronic watch was operated in a state of a curved radius of 1 mm or less and operated normally. In addition, even after recovery of the curve deformation, the electronic clock worked without any problems. This means that Example 1 has mechanical and electrical flexibility and resilience against curve deformation.

In addition, referring to FIG. 12D, it can be seen that Example 1 has excellent elasticity because it includes an elastic electrolyte layer on which nylon fibers are supported. In Example 1, the length of the initial 12 cm to 24 cm can be increased by two times, and can be easily restored to the initial length. And, when Example 1 was increased by about 25%, the discharge current increased from 16.768 mA to 16.919 mA, because the contact area between the positive electrode, the negative electrode, and the electrolyte increased in the increased state. When Example 1 was increased to 60% or 100%, the discharge current did not decrease any more, and it can be seen that the performance of the battery was not affected by this elastic behavior. However, when returning to the original state from the stretched state, the discharge current decreased by 0.205 mA, because the position of the carbon fiber anode was shifted due to different strain rates of the gel electrolyte and the carbon fibers during the stretching process.

Meanwhile, evaluation of the discharge performance of the battery according to whether or not the platinum catalyst was deposited on the carbon fiber anode was performed, and the results are shown in FIG. 13.

13 is a graph showing discharge characteristics of an EGILM air battery according to whether carbon fiber is deposited with a platinum catalyst according to an experimental example of the present invention. Referring to FIG. 13, Example 1 including a carbon fiber anode deposited on a platinum catalyst improved discharge performance by about 1.5 times compared to Comparative Example 1. In the case of Example 1, a current density of 1.480 mA to 1.505 mA cm ^-2 was shown at 0.8 V, which is a value corresponding to about three times the current density of a conventionally reported cable-type zinc-air battery.

Experimental Example 6: Evaluation of Life Characteristics of EGILM Air Battery

A life characteristic test was performed using the EGILM air battery of Example 1, and the results are shown in FIG. 14. 15 is a graph showing the results of a life characteristic experiment of an EGILM air battery according to an experimental example of the present invention.

Referring to FIG. 14, at a current density of 0.2 mA cm ^-2 , a lifespan of 15 hours or more was exhibited, and at a current density of 0.5 mA cm ^-2 , a lifespan of about 5 hours was exhibited. As a result of calculating the energy density of this battery by measuring the weight of the EGILM consumed after discharging, the current densities of 0.2 and 0.5 mA cm ^-2 showed 303.2 and 248.4 Wh kg ^-1 , respectively.

Although the present invention has been shown and described with reference to a preferred embodiment as described above, it is not limited to the above embodiment, and within the scope not departing from the spirit of the present invention, various It can be transformed and changed. Such modifications and variations should be viewed as falling within the scope of the present invention and the appended claims.

10: eutectic liquid metal air battery
100: liquid metal cathode
110: negative electrode current collector
120: eutectic liquid metal anode active material
200: elastic electrolyte layer
210: polymer fiber
220: electrolyte
300: carbon fiber anode
310: carbon fiber
320: metal catalyst

Claims (12)

A liquid metal cathode including a eutectic liquid metal anode active material having an anode current collector inserted thereinto and a liquid at room temperature;
An elastic electrolyte layer coated with a gel electrolyte and comprising polymer fibers having elasticity, and surrounding the liquid metal cathode; And
Carbon fiber anode comprising carbon fibers in which at least a part of the elastic electrolyte layer is in contact and a metal catalyst is formed on at least part of the surface
Containing,
Eutectic liquid metal air battery. The method of claim 1,
The eutectic liquid metal anode active material comprises gallium (Ga) and indium (In), a eutectic liquid metal air battery. The method of claim 2,
The eutectic liquid metal anode active material comprises 74.8 parts by weight to 92.8 parts by weight of gallium and 7.2 parts by weight to 25.2 parts by weight of indium, a eutectic liquid metal air battery. The method of claim 1,
The polymer fiber comprises nylon (Nylon), a eutectic liquid metal air battery. The method of claim 1,
The metal catalyst is at least one of platinum (Pt), palladium (Pd) and silver (Ag), a eutectic liquid metal air battery. The method of claim 1,
The eutectic liquid metal air battery in which the current density is controlled according to the injection amount of the eutectic liquid metal anode active material. The method of claim 1,
A eutectic liquid metal air battery having a current density in the range of 1000 μW/cm ^-2 to 1200 μW/cm ^-2 . The method of claim 1,
The eutectic liquid metal air battery is capable of expanding and contracting 90% to 110% of the initial length, a eutectic liquid metal air battery. The method of claim 1,
The elastic electrolyte layer has a cylindrical structure, a eutectic liquid metal air battery. (a) preparing a eutectic liquid metal negative electrode active material that is liquid at room temperature;
(b) supporting a polymer fiber having elasticity in a solution containing a gel electrolyte precursor and polymerizing the gel electrolyte precursor;
(c) forming an elastic electrolyte layer by rolling the polymer fiber; And
(d) forming a carbon fiber anode such that at least a portion of the elastic electrolyte layer is in contact, and forming a liquid metal cathode by disposing the eutectic liquid metal anode active material and an anode current collector inside the elastic electrolyte layer.
Containing, a method of manufacturing a eutectic liquid metal air battery. The method of claim 10,
The eutectic liquid metal anode active material comprises gallium (Ga) and indium (In), a method of manufacturing a eutectic liquid metal air battery. The method of claim 10,
The carbon fiber anode includes carbon fibers having a metal catalyst formed on at least a portion of the surface thereof, and the metal catalyst is formed on the carbon fibers by an electrochemical deposition method.

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