KR20210106331A - Electrode structure for cathode of zinc-air battery, and method of fabricating of the same - Google Patents

Abstract

An electrode structure for the cathode of a zinc-air battery is provided. The electrode structure for the cathode of the zinc-air battery may include a membrane formed of a compound of copper, phosphorus, and sulfur and in which a plurality of fibrillated fibers form a network. The manufacturing cost can be reduced and the manufacturing process can be simplified.

Description

Electrode structure for cathode of zinc-air battery, and manufacturing method thereof

The present application relates to an electrode structure and a method for manufacturing the same, and more particularly, to an electrode structure for a positive electrode of a zinc-air battery including a membrane formed of a plurality of fibers and a method for manufacturing the same.

As mid-to-large high-energy applications such as electric vehicles and energy storage systems (ESS) are growing rapidly beyond the existing rechargeable batteries for small devices and home appliances, the market value of the secondary battery industry is only about 22 billion dollars in 2018 However, it is expected to grow to about $118 billion by 2025. As such, in order for secondary batteries to be used as medium and large-sized energy storage media, price competitiveness, energy density, and stability that are significantly improved compared to the current level are required.

According to these technical needs, various electrodes for secondary batteries have been developed.

For example, Korean Patent Laid-Open Publication No. 10-2019-0139586 discloses a carbon nanotube and RuO2 deposited on a surface of the carbon nanotube, wherein the RuO2 is deposited on a defective surface of the carbon nanotube, and the RuO2 has a particle size of 1.0 to 4.0 nm, and the RuO2 inhibits carbon decomposition at the surface defect site of the carbon nanotube, and promotes the decomposition of Li2O2 formed on the surface of the carbon nanotube. An electrode for a lithium-air battery. has been disclosed.

One technical problem to be solved by the present application is to provide an electrode structure for a positive electrode of a zinc-air battery, and a method for manufacturing the same.

Another technical problem to be solved by the present application is to provide an electrode structure for a positive electrode of a zinc-air battery having a low manufacturing cost and a simple manufacturing process, and a manufacturing method thereof.

Another technical problem to be solved by the present application is to provide an electrode structure for a positive electrode of a zinc-air battery having improved ORR, OER, and HER characteristics, and a method for manufacturing the same.

Another technical problem to be solved by the present application is to provide an electrode structure for a positive electrode of a zinc-air battery having a long lifespan and high stability, and a method for manufacturing the same.

The technical problem to be solved by the present application is not limited to the above.

In order to solve the above technical problem, the present application provides an electrode structure for a positive electrode of a zinc-air battery.

According to an embodiment, the electrode structure for the positive electrode of the zinc-air battery may include a membrane formed of a compound of copper, phosphorus, and sulfur and in which a plurality of fibrillated fibers form a network.

According to an embodiment, the plurality of fibers formed of a compound of copper, phosphorus, and sulfur may include a plurality of stems and a plurality of branches branched from the plurality of stems.

According to an embodiment, the plurality of stems and the plurality of branches may include being manufactured in different processes.

According to an embodiment, the membrane of the electrode structure may have a sponge structure and include a flexible one.

According to an embodiment, according to the charging and discharging states of the zinc-air battery, the lattice spacing of the membrane of the electrode structure observed by HRTEM may include reversibly increasing or decreasing.

According to an embodiment, the electrode structure may include a membrane formed of a compound of copper and sulfur and in which a plurality of fibrillated fibers form a network.

According to an embodiment, the compound of copper and sulfur may include a compound represented by the following <Formula 1>.

<Formula 1>

CuS _x

(0.35≤x≤0.6)

In order to solve the above technical problem, the present application provides a zinc-air battery.

According to an embodiment, the zinc-air battery may include a positive electrode including the electrode structure according to the above-described embodiment, a zinc negative electrode on the positive electrode, and an electrolyte between the positive electrode and the zinc negative electrode. .

In order to solve the above technical problem, the present application provides a method of manufacturing an electrode structure.

According to an embodiment, the method for manufacturing the electrode structure includes preparing a first precursor having a chalcogen element, a second precursor having phosphorus, and a third precursor having a transition metal, the first precursor, the second mixing a precursor and the third precursor, adding a first reducing agent to prepare a mixture, coprecipitating the mixture to prepare an intermediate product having a plurality of stems, and adding a second reducing agent to the intermediate product And as a method of heat treatment under pressure, by branching a plurality of branches from the plurality of stems, it may include the step of preparing a plurality of fibrillated fibers containing the transition metal, the chalcogen element, and phosphorus.

According to an embodiment, the first precursor is dithiooxamide, Dithiobiuret, Dithiouracil, Acetylthiourea, Thiourea, N-methylthiourea, Bis(phenylthio)methane, 2-Imino-4-thiobiuret, N,N′-Dimethylthiourea, Ammonium sulfide, Methyl methanesulfonate, Sulfur powder, sulphates, N,N-Dimethylthioformamide, or at least one of Davy Reagent methyl, the second precursor is tetradecylphosphonic acid, ifosfamide, Octadecylphosphonic acid, Hexylphosphonic acid, Trioctylphosphine, Phosphoric acid, Triphenyl At least one of Ammonium Phosphide, pyrophosphates, Davy Reagent methyl, Cyclophosphamide monohydrate, Phosphorus trichloride, Phosphorus (V) oxychloride, Thiophosphoryl chloride, Phosphorus pentachloride, or Phosphorus pentasulfide, wherein the third precursor is copper (II) copper chloride, ) may include at least one of sulfate, copper(II) nitrate, copper selenide, copper oxychloride, cupric acetate, copper carbonate, copper thiocyanate, copper sulfide, copper hydroxide, copper naphthenate, or copper (II) phosphate.

According to an embodiment, the method of manufacturing the electrode structure may further include adding a chalcogen element source having a chalcogen element together with the second reducing agent.

According to one embodiment, in the cooled state, it may include adding the second reducing agent.

According to an embodiment, the first reducing agent includes at least one of Ammonium hydroxide, Ammonium chloride, or Tetramethylammonium hydroxide, and the second reducing agent is Triton X-165, Triton X-102, Triton X-45, Triton X-114 may include at least one of Triton X-405, Triton X-101, Trimesic acid, Diamide, Peroxynitrite, formaldehyde, Thimerosal, or chloramine-T.

According to an embodiment, the chalcogen element may include sulfur, and the transition metal may include copper.

The method of manufacturing an electrode structure according to an embodiment of the present application includes preparing a first precursor having a chalcogen element, a second precursor having phosphorus, and a third precursor having a transition metal, the first precursor, the second mixing a precursor and the third precursor, adding a first reducing agent to prepare a mixture, coprecipitating the mixture to prepare an intermediate product having a plurality of stems, and adding a second reducing agent to the intermediate product And as a method of heat treatment under pressure, by branching a plurality of branches from the plurality of stems, it may include the step of preparing a plurality of fibrillated fibers containing the transition metal, the chalcogen element, and phosphorus.

Accordingly, the manufacturing process of the electrode structure can be simplified, and the electrode structure can be easily manufactured at low cost.

In addition, the electrode structure may have high electrochemical properties, and thus, the charge/discharge capacity and lifespan characteristics of a zinc-air battery using the electrode structure as a positive electrode may be improved.

1 is a flowchart for explaining a method of manufacturing an electrode structure for a positive electrode of a zinc-air battery according to an embodiment of the present application.
FIG. 2 is a view for explaining a manufacturing process of an electrode electrode structure for a positive electrode of a zinc-air battery according to an embodiment of the present application.
3 is a photograph of an electrode structure prepared according to Experimental Example 1 of the present application.
4 is a stress-strain graph of the electrode structure prepared according to Experimental Example 1 of the present application.
5 is an XRD graph of an electrode structure prepared according to Experimental Example 1 of the present application.
6 is an XRD graph of an electrode structure prepared according to Experimental Example 2 of the present application.
7 is an XRD graph of an electrode structure prepared according to Experimental Example 3 of the present application.
8 is an XRD graph of an electrode structure prepared according to Experimental Example 4 of the present application.
9 is an SEM photograph of the electrode structure according to Experimental Example 1 of the present application.
10 is a TEM photograph of the electrode structure according to Experimental Example 1 of the present application.
11 shows a simulation of an atomic structure of an electrode structure and lattice stripes according to Experimental Example 1 of the present application.
12 is a SEAD pattern of the electrode structure according to Experimental Example 1 of the present application.
13 is a HAADF-STEM image of an electrode structure according to Experimental Example 1 of the present application.
14 is a graph for explaining the specific surface area and pores of the electrode structure according to Experimental Example 1 of the present application.
15 is an XPS measurement graph of an electrode structure according to Experimental Example 1, Experimental Example 3, and Experimental Example 4 of the present application.
16 is a TGA measurement result of the electrode structure according to Experimental Example 1 of the present application.
17 is a CV (Cyclic voltammogram) graph for explaining the ORR characteristics of the electrode structures according to Experimental Example 1 and Experimental Example 2 of the present application.
18 is a CV graph for explaining ORR characteristics of electrode structures and Pt/C electrodes according to Experimental Example 3 and Experimental Example 4 of the present application.
19 is a linear sweep voltammetry (LSV) graph for explaining ORR characteristics of an electrode structure, a Pt/C electrode, and a carbon fiber according to Experimental Examples 1 to 4 of the present application.
20 is a Rotating Ring Disk Electrode (RRDE) polarization plot and an electron transfer number graph of an electrode structure and a Pt/C electrode according to Experimental Examples 1 to 4 of the present application.
21 is a graph comparing the chemical durability of the electrode structure and the Pt/C electrode according to Experimental Example 1 of the present application.
22 is an Electrochemical Impedance Spectroscopy (EIS) graph for explaining the ORR characteristics of electrode structures and carbon fibers according to Experimental Example 1, Experimental Example 3, and Experimental Example 4 of the present application.
23 is an LSV and CV graph according to the number of cycles for explaining the ORR characteristics of the electrode structure according to Experimental Example 1 of the present application.
24 is a graph of CV and LSV according to the number of cycles of a Pt/C electrode.
25 is a graph illustrating a chronoamperometric measurement and Faraday efficiency measurement for explaining the ORR characteristics of the electrode structure and the Pt/C electrode according to Experimental Example 1 of the present application.
26 is a gas chromatography measurement result for explaining the OER characteristics of the electrode structure according to Experimental Example 1 of the present application.
27 is an LSV graph and a tafel profile for explaining OER characteristics of an electrode structure, a carbon fiber, and a RuO2 electrode according to Experimental Examples 1 to 4 of the present application.
28 is an EIS graph for explaining Experimental Example 1, Experimental Example 3, Experimental Example 4, and OER characteristics of carbon fibers of the present application.
29 is an LSV graph according to the number of cycles for explaining the OER characteristics _{of the electrode structure and the RuO 2} electrode according to Experimental Example 1 of the present application.
30 is a chronoamperometric measurement graph for explaining OER characteristics of the electrode structure and the RuO2 electrode according to Experimental Example 1 of the present application and Faraday efficiency is measured.
31 is a graph for explaining bifunctional oxygen characteristics of electrode structures, Pt/C electrodes, RuO2 electrodes, and carbon fibers according to Experimental Examples 1 to 4 of the present application.
32 is a graph comparing the bifunctional oxygen properties of the electrode structure according to Experimental Example 1 of the present application and another electrode reported to date.
33 is an LSV graph for explaining HER characteristics of Experimental Examples 1 to 4, Pt/C electrodes, and carbon fibers of the present application.
34 is a chronoamperometric measurement graph for explaining the HER characteristics of the electrode structure and the Pt/C electrode according to Experimental Example 1 of the present application.
35 is a Tafel profile for explaining the HER characteristics of Experimental Examples 1 to 4, Pt/C electrodes, and carbon fibers of the present application.
36 is an LSV graph according to the number of cycles for explaining the HER characteristics of the electrode structure and the Pt/C electrode according to Experimental Example 1 of the present application.
37 is a graph comparing the HER characteristics of the electrode structure according to Experimental Example 1 of the present application and another electrode reported to date.
38 is an LSV graph for explaining ORR characteristics in an acidic environment of the electrode structure and the Pt/C electrode according to Experimental Example 1 of the present application.
39 is an LSV graph for explaining HER characteristics in an acidic environment of the electrode structure and the Pt/C electrode according to Experimental Example 1 of the present application.
40 is a graph comparing HER characteristics in an acidic environment of the electrode structure according to Experimental Example 1 of the present application and other electrodes reported to date.
41 is a mass activity graph for comparing ORR, OER, and HER characteristics of _{electrode structures, Pt/C electrodes, and RuO 2} electrodes according to Experimental Examples 1 and 2 of the present application.
42 is an in-situ XRD measurement graph of the electrode structure according to Experimental Example 1 in the charging/discharging state of the secondary battery according to Experimental Example 1 of the present application.
43 is a HRTEM photograph of the electrode structure according to Experimental Example 1 in the charging/discharging state of the secondary battery according to Experimental Example 1 of the present application.
44 is a HRTEM photograph of the electrode structure according to Experimental Example 1 in the charging/discharging state of the secondary battery according to Experimental Example 1 of the present application.
45 is a graph evaluating OER, ORR, and HER characteristics according to crystal planes in the electrode structure according to Experimental Example 1 of the present application.
46 is a graph evaluating ORR, OER, and HER characteristics according to the composition ratio of P and S of the electrode structure according to Experimental Example 1 of the present application.
47 is Cu 2p, P 2p, and S 2p XPS spectra according to the composition ratio of P and S of the electrode structure according to Experimental Example 1 of the present application.
48 is a graph evaluating ORR, OER, and HER characteristics according to the composition ratio of Cu and S of the electrode structure according to Experimental Example 3 of the present application.
49 is an XRD graph according to the composition ratio of Cu and S of the electrode structure according to Experimental Example 3 of the present application.
50 is a graph showing lattice parameters according to the composition ratio of Cu and S of the electrode structure according to Experimental Example 3 of the present application.
51 is a graph comparing the discharge voltage according to the current density of the zinc-air battery including the electrode structure according to Experimental Example 1 of the present application.
52 is a graph for explaining the charge/discharge capacity of the zinc-air battery according to Experimental Example 1 of the present application.
53 is a graph of measuring voltage values according to the number of times of charging and discharging of the zinc-air battery according to Experimental Example 1 of the present application.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical spirit of the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

In addition, in various embodiments of the present specification, terms such as first, second, third, etc. are used to describe various components, but these components should not be limited by these terms. These terms are only used to distinguish one component from another. Accordingly, what is referred to as a first component in one embodiment may be referred to as a second component in another embodiment. Each embodiment described and illustrated herein also includes a complementary embodiment thereof. In addition, in the present specification, 'and/or' is used to mean including at least one of the elements listed before and after.

In the specification, the singular expression includes the plural expression unless the context clearly dictates otherwise. In addition, terms such as "comprise" or "have" are intended to designate that a feature, number, step, element, or a combination thereof described in the specification is present, and one or more other features, numbers, steps, configuration It should not be construed as excluding the possibility of the presence or addition of elements or combinations thereof. Also, in the present specification, the term “connection” is used to include both indirectly connecting a plurality of components and directly connecting a plurality of components.

In addition, in the following description of the present invention, if it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

1 is a flowchart for explaining a method of manufacturing an electrode structure for a positive electrode of a zinc-air battery according to an embodiment of the present application, and FIG. 2 is a manufacturing process of an electrode electrode structure for a positive electrode of a zinc-air battery according to an embodiment of the present application It is a drawing for explaining.

1 and 2, a first precursor having a chalcogen element, a second precursor having phosphorus, and a third precursor having a transition metal may be prepared (S110).

According to one embodiment, the chalcogen element may include sulfur. In this case, for example, the first precursor is dithiooxamide, Dithiobiuret, Dithiouracil, Acetylthiourea, Thiourea, N-methylthiourea, Bis(phenylthio)methane, 2-Imino-4-thiobiuret, N,N′Ammonium sulfide, Methyl methanesulfonate , Sulfur powder, sulphates, N,N-Dimethylthioformamide, and may contain at least one of Davy Reagent methyl.

Alternatively, according to another embodiment, the chalcogen element may include at least one of oxygen, selenium, or tellurium.

For example, the second precursor is tetradecylphosphonic acid, ifosfamide, Octadecylphosphonic acid, Hexylphosphonic acid, Trioctylphosphine, Phosphoric acid, Triphenylphosphine, Ammonium Phosphide, pyrophosphates, Davy Reagent methyl, Cyclophosphamide monohydrate, Phosphorus (V methyl, Cyclophosphamide) triphosphoryl, Phosphorus. It may include at least one of chloride, Phosphorus pentachloride, or Phosphorus pentasulfide.

According to an embodiment, different heterogeneous species including phosphorus may be used as the second precursor. For example, as the second precursor, a mixture of tetradecylphosphonic acid and ifosfamide 1:1 (M%) may be used. Accordingly, the stoichiometric ratio of the transition metal, phosphorus, and the chalcogen element can be controlled to 1:1:1. As a result, as will be described later, the positive electrode according to the embodiment of the present application may have a covellite structure, and the electrochemical properties of the positive electrode may be improved.

According to an embodiment, the transition metal may include copper. In this case, for example, the third precursor is copper chloride, copper(II) sulfate, copper(II) nitrate, copper selenide, copper oxychloride, cupric acetate, copper carbonate, copper thiocyanate, copper sulfide, copper hydroxide, copper It may include at least one of naphthenate, or copper(II) phosphate.

Alternatively, according to another embodiment, the transition metal may include at least one of magnesium, manganese, cobalt, iron, nickel, titanium, zinc, aluminum, and tin.

A mixture may be prepared by mixing the first precursor, the second precursor, and the third precursor, and adding a first reducing agent (S120).

After the first precursor, the second precursor, and the third precursor are mixed in a solvent, the first reducing agent may be added. For example, the solvent may be a mixture of ethanol and ethylenediamine. Alternatively, as another example, the solvent may be a mixture of ethanol and toluene.

According to an embodiment, according to the type and mixing ratio of the solvent, the direction of the crystal plane of the electrode structure to be described later may be controlled. In other words, depending on the type and mixing ratio of the solvent, the development of the (101) crystal plane in the electrode structure may be controlled, and thereby, the electrochemical properties of the electrode structure may be controlled.

According to an embodiment of the present application, the solvent may be selected so that a (101) crystal plane can be developed in the electrode structure (eg, 1:3 volume ratio mixing of ethanol and ethylenediamine), thereby, the Electrochemical properties (eg, ORR, OER, HER) of the electrode structure may be improved.

After the first precursor, the second precursor, and the third precursor are mixed in the solvent, nucleation and crystallization may proceed as shown in FIG. 2A .

For example, the first reducing agent may include at least one of Ammonium hydroxide, Ammonium chloride, and Tetramethylammonium hydroxide.

By co-precipitating the mixture including the first precursor, the second precursor, the third precursor, the first reducing agent, and the solvent, an intermediate product including a plurality of stems may be prepared ( S130 ).

The mixture may be heat treated to form an intermediate product, as shown in FIG. 1( b ). The intermediate product may have a plurality of stems, and the plurality of stems may constitute a network with each other.

For example, the mixture to which the first reducing agent is added may be reflux heat treated at 120° C., and then washed with deionized water and ethanol.

The first reducing agent may perform the function of the reducing agent while heat-treating, maintain pH and increase the reaction rate. Accordingly, the intermediate product having the plurality of stems can be easily prepared. For example, when the transition metal is copper and the chalcogen element is sulfur, the intermediate structure may be CuPS having a cobelite crystal structure.

In a method of adding a second reducing agent to the intermediate product and heat-treating under pressure, a plurality of fibrillated fibers including the transition metal, the chalcogen element, and phosphorus are obtained by branching a plurality of branches from the plurality of stems. can be manufactured (S140).

According to an embodiment, after the intermediate product and the second reducing agent are added to deionized water, a pressure heat treatment process may be performed.

For example, the second reducing agent is, Triton X-165, Triton X-102, Triton X-45, Triton X-114 Triton X-405, Triton X-101, Trimesic acid, Diamide, Peroxynitrite, formaldehyde, Thimerosal, Or it may include at least one of chloramine-T.

According to an embodiment, together with the second reducing agent, a chalcogen element source including the chalcogen element may be further added. Due to this, the chalcogen element lost in the reaction process is supplemented by the chalcogen element source, the electrode structure of a sponge structure in which a plurality of fibrillated fibers to be described later constitute a network can be easily formed .

For example, when the chalcogen element is sulfur, the chalcogen element source may include at least one of sodium bisulfite, sodium sulfate, sodium sulfide, sodium thiosulfate, sodium thiomethoxide, sodium ethanethiolate, or sodium methanethiolate.

The process of mixing the intermediate product and the second reducing agent in deionized water may be performed in a cooled state. It can be prevented that the reaction rate is excessively increased by the heat generated in the process of adding the second reducing agent, thereby improving the electrochemical properties of the electrode structure to be described later.

As described above, by adding a second reducing agent to the intermediate product and heat-treating under pressure, as shown in FIG. The electrode structure of a sponge structure in which a plurality of fibers formed into a network may be formed.

The electrode structure having a sponge structure may be immersed in liquid nitrogen after being washed with deionized water and ethanol. Due to this, mechanical properties and flexibility of the electrode structure of the sponge structure may be improved.

In addition, after being immersed in liquid nitrogen, the electrode structure of the sponge structure is freeze-dried, and the remaining solvents are removed, so that the secondary reaction can be minimized.

As described above, the electrode structure may include a membrane having a sponge structure in which the plurality of fibrillated fibers in which the plurality of branches are branched from the plurality of stems constitute a network. For this reason, the electrode structure may have a porous structure provided with a plurality of pores having a size of 1 to 2 nm, and may be flexible.

In addition, as described above, the type and ratio of the solvent mixed with the first precursor, the second precursor, and the third precursor may be controlled, so that a (101) crystal plane may be developed in the electrode structure. Accordingly, during XRD analysis of the electrode structure, a peak value corresponding to a (101) crystal plane may have a maximum value compared with a peak value corresponding to another crystal plane. In XRD measurement, the peak value corresponding to the (101) crystal plane can be observed in the range of the 2θ value of 19° to 21°.

The plurality of fibers constituting the electrode structure may include a compound of the transition metal, phosphorus, and the chalcogen element. For example, when the transition metal is copper and the chalcogen element is oxygen, the fiber may be represented by the following <Formula 1>.

<Formula 1>

CuP _x S _y

When the fibers constituting the electrode structure are expressed as in <Formula 1>, x+y=1, 0.3≤x≤0.7, 0.3≤y≤0.7.

If, in <Formula 1>, x is less than 0.3 or greater than 0.7, and y is less than 0.3 or greater than 0.7, ORR, OER, and HER characteristics of the electrode structure may be reduced, and thus the electrode structure In the charging/discharging process of a zinc-air battery including as a positive electrode, the electrode structure may not react reversibly.

However, according to an embodiment of the present application, when the electrode structure is expressed as CuP _x S _y , the composition ratio of P may be 0.3 or more and 0.7 or less, and the composition ratio of S may be 0.3 or more and 0.7 or less. Accordingly, ORR, OER, and HER characteristics of the electrode structure may be improved, and charge/discharge characteristics and lifespan characteristics of a zinc-air battery including the electrode structure as a positive electrode may be improved.

Alternatively, unlike the above, according to one modification, the electrode structure may be a compound of the transition metal and the chalcogen element (eg, sulfur). Alternatively, according to another modification, the electrode structure may be a compound of the transition metal and phosphorus.

When the zinc-air battery including the electrode structure as a positive electrode performs charging and discharging, the lattice spacing of the fibers included in the electrode structure may be reversibly changed. Specifically, when the zinc-air battery is charged, the lattice spacing may be 0.478 nm, and when the zinc-air battery is discharged, the lattice spacing may be 0.466 nm. The lattice spacing of the fibers can be confirmed by HRTEM.

According to an embodiment of the present application, in a method of mixing the first precursor having the chalcogen element, the second precursor having phosphorus, and the third precursor having the transition metal, and co-precipitating and heat treatment under pressure, fibrils The electrode structure in the form of a membrane in which the plurality of fibers formed into a network may be manufactured.

The electrode structure having high electrochemical properties can be manufactured by an inexpensive method.

In addition, the electrode structure is manufactured by co-precipitation and heat treatment under pressure, so that mass production is easy and the manufacturing process is simplified, the electrode structure for a positive electrode of a zinc-air battery can be provided.

Hereinafter, a zinc-air battery including the electrode structure according to an embodiment of the present application described above will be described.

The zinc-air battery may include a positive electrode, a negative electrode, and an electrolyte between the positive electrode and the negative electrode.

The negative electrode may include zinc. Alternatively, the negative electrode may include lithium.

The electrolyte may be a solid electrolyte. According to an embodiment, as will be described later, the electrolyte may be a membrane in which the bacterial cellulose and the composite fiber including the chitonic acid bound to the bacterial cellulose constitute a network. Alternatively, the electrolyte may be an oxide-based, sulfide-based, or polymer-based electrolyte.

The positive electrode may include the electrode structure described with reference to FIGS. 1 and 2 , and oxygen may be used as a positive electrode active material.

Hereinafter, an electrode structure according to a specific experimental example of the present application, and a characteristic evaluation result of a zinc-air battery including the same will be described.

Preparation of electrode structure and secondary battery according to Experimental Example 1

Prepare dithiooxamide as a first precursor having sulfur, prepare a mixture (1:1 M%) of tetradecylphosphonic acid and ifosfamide as a second precursor having phosphorus, prepare copper chloride as a third precursor having copper, and prepare as a solvent A mixture of ethanol and ethylenediamine (1:3v/v%) was prepared.

After the first to third precursors were added to the solvent, a suspension was prepared by stirring.

Thereafter, 2.5M% of ammonium hydroxide was added as a first reducing agent, stirred for 2 hours, and heat treated at 120° C. for 6 hours, after which an intermediate product was obtained, washed with deionized water and ethanol, and dried in a vacuum at 50° C. did.

In an ice bath, the intermediate product was mixed and stirred in 20 ml of deionized water with Triton X-165 as a secondary reducing agent and sodium bisulfite as an elemental sulfur source. Thereafter, pressure heat treatment was performed at 120° C. for 24 hours to prepare a membrane in which a plurality of fibrillated fibers formed of a compound of copper, phosphorus, and sulfur constitute a network.

The membrane was washed with deionized water and ethanol, adjusted to neutral pH, stored at -70°C for 2 hours, immersed in liquid nitrogen, and freeze-dried in vacuum, CuPS according to Experimental Example 1 in which (101) crystal plane was developed An electrode structure was prepared.

In the manufacturing process of the electrode structure according to Experimental Example 1, by adjusting the ratio of the first precursor having sulfur and the second precursor having phosphorus, the ratio of P and S in CuPS was 0.1:0.9, 0.2:0.8, respectively, Adjusted to 03:0.7, 0.5:0.5, 0.7.0.3, and 0.9:0.1.

A zinc-air battery according to Experimental Example 1 was prepared by using the CuPS electrode structure according to Experimental Example 1 as a positive electrode, and stacking a solid electrolyte according to Experimental Example to be described later, and a patterned zinc negative electrode.

Preparation of an electrode structure according to Experimental Example 2

The same method as in Experimental Example 1 described above was performed, except that a mixture of ethanol and toluene (1:1 v/v%) was used as a solvent, and pressure heat treatment was performed at 150° C. for 24 hours, CuPS according to Experimental Example 2 An electrode structure was prepared.

In the manufacturing process of the electrode structure according to Experimental Example 1, by adjusting the ratio of the first precursor having sulfur and the second precursor having phosphorus, the ratio of P and S in CuPS was 0.1:0.9, 0.2:0.8, respectively, Adjusted to 03:0.7, 0.5:0.5, 0.7.0.3, and 0.9:0.1.

Preparation of an electrode structure according to Experimental Example 3

A CuS electrode structure according to Experimental Example 3 was prepared in the same manner as in Experimental Example 2 described above, but by omitting the second precursor having phosphorus.

Preparation of an electrode structure according to Experimental Example 4

A CP electrode structure according to Experimental Example 4 was prepared by performing the same method as in Experimental Example 2 described above, but omitting the first precursor having sulfur.

Preparation of a solid electrolyte according to an experimental example

Acetobacter xylinum was prepared as a bacterial strain, and a chitosan derivative was prepared. The chitosan derivative is a suspension of 1 g of chitosan chloride dissolved in 1% (v/v) aqueous acetic acid with 1M of glycidyltrimethylammonium chloride in N ₂ atmosphere at 65° C. for 24 hours. After treatment for a while, it was prepared by precipitation and filtration with ethanol several times.

Pineapple juice (2% w/v), yeast (0.5% w/v), peptone (0.5% w/v), disodium phosphate (0.27% w/v), citric acid (0.015% w/v), and the above A Hestrin-Schramm (HS) culture medium containing a chitosan derivative (2% w/v) was prepared and steam sterilized at 121° C. for 20 minutes. In addition, Acetobacter xylinum was activated in a pre-cultivation Hestrin-Schramm (HS) culture medium at 30° C. for 24 hours, and then maintained at pH 6 by adding acetic acid.

Then, Acetobacter xylinum was cultured in Hestrin-Schramm (HS) culture medium at 30 °C for 7 days.

The harvested bacterial pellicles were washed with deionized water to neutralize the pH of the supernatant and dehydrated in vacuum at 105°C. The resulting cellulose was demineralized with 1 N HCl for 30 minutes (mass ratio 1:15, w/v) to remove excess reagent, and then using deionized water several times until the supernatant became neutral pH. It was purified by centrifugation. Finally, after evaporating all solvents at 100° C., a base composite fiber (chitosan-bacterial cellulose (CBC)) was prepared.

2 g of the base composite fiber fibers dispersed in 2 mM TEMPO aqueous solution were reacted with NaBr (1.9 mM). 5 mM NaClO was used as the oxidizing agent.

The reaction suspension was stirred ultrasonically, and the reaction was allowed to proceed at room temperature for 3 hours. The pH of the suspension was maintained at 10 by continuous addition of 0.5M NaOH solution. Then, 1N HCL was added to the suspension to keep the pH neutral for 3 hours. The resulting oxidized pulp in the suspension was washed 3 times with 0.5 N HCl, and the supernatant was brought to neutral pH with deionized water.

The washed pulp was exchanged with acetone, toluene for 30 minutes and dried to evaporate the solvent, and finally, a first composite fiber (oCBC) fiber was obtained.

1 g of the base composite fiber dispersed in N,N-dimethylacetamide (35ml) solution was reacted with a LiBr (1.25g) suspension while stirring for 30 minutes. N-bromosuccinimide (2.1 g) and triphenylphosphine (3.2 g) were used as coupling agents. The two reaction mixtures were stirred for 10 minutes and reacted at 80° C. for 60 minutes.

The reaction suspension was then cooled to room temperature and added to deionized water, filtered, rinsed with deionized water and ethanol, and freeze-dried to obtain brominated base conjugate fiber (bCBC) fibers.

The brominated base composite fiber was dissolved in 100 ml of N,N-dimethylformamide and reacted with 1.2 g of 1,4-Diazabicyclo[2.2.2]octane coupling agent.

Thereafter, the mixture was sonicated for 30 minutes and then reacted at room temperature for 24 hours. The resulting solution was mixed with diethyl ether, washed with diethyl ether/ethyl acetate 5 times, and freeze-dried to obtain a second composite fiber (Covalently quaternized CBC (qCBC)).

Using ultrasound, the first composite fiber (oCBC) and the second composite fiber (qCBC) were mixed with methylene chloride, 1,2-Propanediol, and acetone in the same weight ratio (8:1:1 v/v/v% ), 1 wt% of glutaraldehyde as a crosslinking agent and 0.3 wt% of N,N-Diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide as an initiator were added.

A vacuum chamber (200 Pa) was used to remove air bubbles from the gel suspension and cast on glass at 60° C. for 6 hours. The composite fiber membrane was peeled off while coagulated with deionized water, rinsed with deionized water, and vacuum dried.

Solid electrolytes (CBCs) were prepared by ion exchange with 1 M KOH aqueous solution and 0.1 M ZnTFSI at room temperature for 6 hours, respectively. Thereafter, in order to avoid reaction and carbonate formation with _{CO 2} , washing and immersion processes were performed with deionized water in an _{N 2 atmosphere.}

3 is a photograph of the electrode structure prepared according to Experimental Example 1 of the present application, and FIG. 4 is a stress-strain graph of the electrode structure prepared according to Experimental Example 1 of the present application.

Referring to FIGS. 3 and 4 , the electrode structure (CuP _0.5 S _0.5 ) prepared according to Experimental Example 1 described above was photographed, and strain according to stress was measured at a relative humidity of about 40% and room temperature conditions.

As shown in FIG. 3 , it can be seen that the electrode structure according to Experimental Example 1 has a length of about 10 cm and is flexible.

In addition, as shown in FIG. 4 , even after applying the stress for 1000 times, it has a high recovery rate of about 94%, and it can be confirmed that the electrode structure according to Experimental Example 1 has high flexibility, compressibility, and elasticity.

5 is an XRD graph of an electrode structure prepared according to Experimental Example 1 of the present application, FIG. 6 is an XRD graph of an electrode structure prepared according to Experimental Example 2 of the present application, and FIG. 7 is an XRD graph of Experimental Example 3 of the present application It is an XRD graph of the electrode structure prepared in accordance with, and FIG. 8 is an XRD graph of the electrode structure prepared according to Experimental Example 4 of the present application.

5 to 8 , according to Experimental Example 1, CuPS electrode structures having various P and S composition ratios, CuPS electrode structures having various P and S composition ratios according to Experimental Example 2, Experimental Examples 3 and 4 XRD measurements of the CS and CP electrode structures according to the method were performed.

As can be seen in FIGS. 5 and 6 , in the CuPS electrode structures according to Experimental Examples 1 and 2, it can be seen that the pattern is changed according to the composition ratio of P and S, and the size of the peak corresponding to the (101) crystal plane It can be seen that is larger than the size of the peak corresponding to the other crystal plane.

In addition, compared with the CuPS electrode structure according to Experimental Example 2 of FIG. 6 , in the case of the CuPS electrode structure according to Experimental Example 1 in which the (101) crystal plane was developed, the size of the peak corresponding to the (101) crystal plane was (101) Compared with the peak values corresponding to the crystal plane other than the crystal plane, it can be confirmed that it is remarkably high.

7 and 8, in the case of CuS and CuP electrode structures according to Experimental Examples 3 and 4, unlike the CuPS electrode structures of Experimental Examples 1 and 2, the peak corresponding to the (101) crystal plane is not large, A peak corresponding to the (101) crystal plane was not observed.

In addition, it can be seen that the CuPS electrode structures of Experimental Examples 1 and 2 have a covellite phase as an orthorhombic crystal structure Pnm21 space group, and the CuS electrode structure of Experimental Example 3 has a hexagonal structure. It can be seen that the CuP electrode structure of Experimental Example 4 has a crystalline structure P6 _{3 /mmc space group, and has a hexagonal crystal structure P6 3} cm space group.

9 is a SEM photograph of the electrode structure according to Experimental Example 1 of the present application, FIG. 10 is a TEM photograph of the electrode structure according to Experimental Example 1 of the present application, and FIG. 11 is an Experimental Example of the present application A simulation of the atomic structure of the electrode structure according to 1 and lattice stripes are shown.

9 to 11 , an SEM picture and a TEM picture were taken for the CuPS electrode structure (CuP _0.5 S _0.5 ) according to Experimental Example 1, and simulations of the atomic structure and lattice stripes were displayed. Figure 10 (a) is a high-resolution (scale bar 2nm) TEM photograph of the electrode structure of Experimental Example 1, Figure 10 (b) is a low-resolution (scale bar 30nm) TEM photograph of the electrode structure of Experimental Example 1, Figure 11 (a) is a simulation showing the atomic arrangement of the (101) crystal plane of the electrode structure of Experimental Example 1, and (b) of FIG. 11 is a topographic plot profile of the lattice stripes of the electrode structure of Experimental Example 1. profile).

As can be seen in FIG. 9 , in the electrode structure of Experimental Example 1, it can be confirmed that a plurality of fibers constitute a network.

In addition, as can be seen in FIGS. 10 and 11 , it can be seen that the lattice spacing of the electrode structure of Experimental Example 1 is 0.466 nm.

12 is a SEAD pattern of the electrode structure according to Experimental Example 1 of the present application, and FIG. 13 is a HAADF-STEM image of the electrode structure according to Experimental Example 1 of the present application.

^{12 and 13 , a SEAD pattern (scale 2nm -1} ) was obtained for the (101) plane of _{the CuPS electrode structure (CuP 0.5} S _0.5 ) according to Experimental Example 1 described above, and HAADF-STEM (High Angle Annular Dark) Field canning Transmission Electron Microscopy) images were taken, and mapping results were shown for Cu, P, and S.

12 and 13 , it can be seen that the electrode structure of Experimental Example 1 has an orthorhombic crystal structure having a (101) crystal plane, and is formed of a compound of Cu, P, and S.

14 is a graph for explaining the specific surface area and pores of the electrode structure according to Experimental Example 1 of the present application.

Referring to FIG. 14 , the BET surface area of the CuPS electrode structure (CuP _0.5 S _{0.5 ) according to Experimental Example 1 described above was measured.} It can be seen that the electrode structure according to Experimental Example 1 has a ^{porous structure with a specific surface area of 1168 m 2} /g, and has a large amount of pores having a size of 1 to 2 nm.

15 is an XPS measurement graph of an electrode structure according to Experimental Example 1, Experimental Example 3, and Experimental Example 4 of the present application.

15 , XPS measurements were performed on the electrode structures according to Experimental Example 1, Experimental Example 3, and Experimental Example 4, and Cu, P of the electrode structures according to Experimental Example 1, Experimental Example 3, and Experimental Example 4 The ratios of , and S were calculated. In addition, the ratio of Cu, P, and S of the electrode structure according to Experimental Example 1, Experimental Example 3, and Experimental Example 4 according to Inductively Coupled Plasma Spectrometer (ICP) and Energy Dispersive X-ray Spectroscopy (EDS) is shown below [ Table 1] to [Table 3] were calculated as shown.

XPS Cu (at%) P(at%) S(at%) Experimental Example 1 (CuPS) 48.92 24.89 26.19 Experimental Example 3 (CuS) 50.44 - 49.56 Experimental Example 4 (CuP) 74.37 25.63 -

ICP Cu (at%) P(at%) S(at%) Experimental Example 1 (CuPS) 48.96 24.86 26.18 Experimental Example 3 (CuS) 50.32 - 49.68 Experimental Example 4 (CuP) 74.16 25.84 -

EDS Cu (at%) P(at%) S(at%) Experimental Example 1 (CuPS) 49.12 24.99 25.89 Experimental Example 3 (CuS) 50.57 - 49.43 Experimental Example 4 (CuP) 74.29 25.71 -

As can be seen from [Table 1] to [Table 3], in the electrode structure according to Experimental Example 1, it can be confirmed that Cu, P, and S have a substantially 1:0.5:0.5 ratio, and according to Experimental Example 3 In the electrode structure, it can be seen that Cu and S have a substantially 1:1 ratio, and in the electrode structure according to Experimental Example 4, it can be confirmed that Cu and P have a substantially 3:1 ratio.

16 is a TGA measurement result of the electrode structure according to Experimental Example 1 of the present application.

Referring to FIG. 16 , _{TGA analysis was performed while the CuPS electrode structure (CuP 0.5} S _0.5 ) according to Experimental Example 1 was heated to 5° C. in nitrogen gas and atmospheric gas atmosphere.

As can be seen from FIG. 16 , it can be seen that the electrode structure according to Experimental Example 1 maintains a stable state at a high temperature. In the nitrogen atmosphere, the weight was lost at 605°C to 732°C, and in the atmospheric gas atmosphere, the weight was lost at 565°C to 675°C. Compared with the atmospheric gas atmosphere, it can be seen that a little more stable in the nitrogen gas atmosphere, which is due to the formation of CuO in the electrode structure according to Experimental Example 1.

In conclusion, it can be confirmed that the electrode structure according to Experimental Example 1 has high thermal stability of the orthorhombic crystal structure.

17 is a CV (Cyclic voltammogram) graph for explaining the ORR characteristics of the electrode structures according to Experimental Examples 1 and 2 of the present application, and FIG. 18 is an electrode structure according to Experimental Examples 3 and 4 of the present application, and a CV graph for explaining the ORR characteristics of the Pt/C electrode.

17 and 18, using 0.1M KOH as an electrolyte, the electrode structures according to Experimental Examples 1 to 4, and the purified current voltage curve of the commercially available Pt / C electrode (20wt%) were measured. . For the electrode structures of Experimental Example 1 and Experimental Example 2, CuP _0.5 S _0.5 was used. In FIGS. 26 and 27 , a black dotted line is a nitrogen saturation condition, and a red solid line is an oxygen saturation condition.

As can be seen in FIGS. 17 and 18 , the oxygen reduction potential of the electrode structures according to Experimental Examples 1 to 4 can be confirmed, and it can be seen that they have excellent ORR characteristics, even compared to the commercialized Pt/C electrode. .

19 is a linear sweep voltammetry (LSV) graph for explaining ORR characteristics of an electrode structure, a Pt/C electrode, and a carbon fiber according to Experimental Examples 1 to 4 of the present application, and FIG. 20 is an Experimental Example of the present application Rotating Ring Disk Electrode (RRDE) polarization plots and electron transfer number graphs of the electrode structures and Pt/C electrodes according to Examples 1 to 4.

19 to 20 , ORR characteristics were compared with respect to the electrode structures according to Experimental Examples 1 to 4, commercially available Pt/C electrodes, and commercially available carbon fibers. For the electrode structures of Experimental Example 1 and Experimental Example 2, CuP _0.5 S _0.5 was used. Further, showing the electrode structure and the Pt / C electrode of RRDE polarization plot and electron transfer coefficient according to the experimental example 1 to experimental example 4, and, OH ₂ of the electrode structural body according to the Experimental Example 1 ^were shown to yield.

As can be seen from FIG. 19 , according to Experimental Example 1, it can be confirmed that the CuPS electrode structure having the (101) crystal plane reinforced has the best ORR characteristics and the highest electron transport coefficient. In addition, although the CuPS electrode structure of Experimental Example 2 and the CuS electrode structure of Experimental Example 3 are also slightly lower than commercial Pt/C, it can be confirmed that they have excellent ORR characteristics.

In conclusion, by using the electrode structures according to Experimental Examples 1 to 3 of the present application, at a lower price than Pt/C, an electrode structure having ORR properties similar to or superior to Pt/C or Pt/C can be manufactured. It can be confirmed that there is

21 is a graph comparing the chemical durability of the electrode structure and the Pt/C electrode according to Experimental Example 1 of the present application.

_{Referring to FIG. 21, using 0.1M KOH, methanol (2M) and CO 2} (10V%) were injected into the electrode structure according to Experimental Example 1 and a commercially available Pt/C electrode at 1600 rpm conditions to measure chemical durability. . For the electrode structure according to Experimental Example 1, CuP _0.5 S _0.5 was used.

As shown in FIG. 21 , in the case of the electrode structure according to Experimental Example 1, it can be confirmed _{that the electrode structure is stably driven even after methanol and CO 2 are injected.} On the other hand, in the case of the Pt/C electrode, when methanol or CO2 is injected, it can be seen that the current value is significantly lowered.

In conclusion, it can be seen that the CuPS electrode structure according to Experimental Example 1 of the present application has a high ORR characteristic as well as excellent chemical resistance as compared to a commercialized Pt/C electrode. Accordingly, it can be seen that the CuPS electrode structure according to Experimental Example 1 of the present application can be stably utilized in an alkaline environment.

22 is an Electrochemical Impedance Spectroscopy (EIS) graph for explaining the ORR characteristics of electrode structures and carbon fibers according to Experimental Example 1, Experimental Example 3, and Experimental Example 4 of the present application.

Referring to FIG. 22 , EIS measurements of the electrode structures and carbon fibers according to Experimental Example 1, Experimental Example 3, and Experimental Example 4 were performed using 0.1M KOH. For the electrode structure according to Experimental Example 1, CuP _0.5 S _0.5 was used.

22, the CuPS electrode structure of Experimental Example 1 has the lowest impedance value, the CuPS electrode structure of Experimental Example 1, the CuS electrode structure of Experimental Example 3, the CP electrode structure of Experimental Example 4, and the carbon fiber sequence It can be confirmed that it has a high ORR characteristic.

23 is an LSV and CV graph according to the number of cycles for explaining the ORR characteristics of the electrode structure according to Experimental Example 1 of the present application, and FIG. 24 is a CV and LSV graph according to the cycle number of the Pt/C electrode, FIG. 25 is a chronoamperometric measurement graph for explaining the ORR characteristics of the electrode structure and the Pt/C electrode according to Experimental Example 1 of the present application and Faraday efficiency is measured.

23 to 25 , LSV and CV measurements were performed according to the number of cycles for the CuPS electrode structure according to Experimental Example 1 and the commercially available Pt/C electrode using 0.1M KOH and under oxygen conditions. In addition, the CuPS electrode structure and the Pt/C electrode according to Experimental Example 1 were measured by a chronoamperometric method under 0.9V conditions, and the Faraday efficiency of the CuPS electrode according to Experimental Example 1 was measured. For the electrode structure according to Experimental Example 1, CuP _0.5 S _0.5 was used.

As can be seen from FIGS. 23 to 25 , it can be seen that the electrode structure according to Experimental Example 1 is stably driven without substantial change even after 30,000 charge/discharge cycles are performed. In addition, it can be seen that it is stably operated without substantial change for about 500 hours, and has a Faraday efficiency of about 98% or more.

On the other hand, in the case of the Pt/C electrode, as the cycle is performed, the current density value is remarkably reduced, and it can be seen that the properties are remarkably deteriorated as compared to the electrode structure of Experimental Example 1.

In conclusion, it can be seen that the CuPS electrode structure according to Experimental Example 1 has a high ORR characteristic and excellent chemical resistance, as well as a long lifespan, as compared to a commercialized Pt/C electrode.

26 is a gas chromatography measurement result for explaining the OER characteristics of the electrode structure according to Experimental Example 1 of the present application.

Referring to FIG. 26 , gas chromatography measurement of the CuPS electrode structure according to Experimental Example 1 was performed under oxygen conditions using 0.1M KOH. For the electrode structure according to Experimental Example 1, CuP _0.5 S _0.5 was used.

As can be seen in FIG. 26 , it can be confirmed that oxygen gas is generated on the surface of the CuPS electrode structure according to Experimental Example 1.

27 is an LSV graph and a tafel profile for explaining OER characteristics of an electrode structure, carbon fiber, and RuO ₂ electrode according to Experimental Examples 1 to 4 of the present application, and FIG. 28 is an Experimental Example of the present application 1, Experimental Example 3, Experimental Example 4, and EIS graphs for explaining OER characteristics of carbon fibers.

Referring to FIGS. 27 and 28 , LSV measurements of the electrode structures, carbon fibers, and RuO ₂ electrodes according to Experimental Examples 1 to 4 were performed, and Tafel values were shown. In addition, EIS measurements of the electrode structures and carbon fibers according to Experimental Example 1, Experimental Example 3, and Experimental Example 4 were performed. For the electrode structures according to Experimental Example 1 and Experimental Example 2, CuP _0.5 S _0.5 was used.

27 and 28, the CuPS electrode structure of Experimental Example 1, the RuO ₂ electrode, the CuPS electrode structure of Experimental Example 2, the CP electrode structure of Experimental Example 4, the CuS electrode structure of Experimental Example 3, and carbon fiber sequence It can be confirmed that it has a high OER characteristic. In particular, it can be seen that the CuPS electrode structure according to Experimental Example 1 has the lowest overpotential value of 260 mV at 10 ^{mAcm -2 and a Tafel value of 58 mVdec -1} , and has significantly higher OER characteristics compared to commercially available RuO _{2 .} know that you have

29 is of an LSV graph, Figure 30 is the electrode structure and RuO ₂ electrode according to Experimental Example 1 of the present application in accordance with the number of cycles for explaining the electrode structure and OER properties of RuO ₂ electrode according to Experimental Example 1 of the present application A chronoamperometric measurement graph and Faraday efficiency were measured to explain the OER characteristics.

Referring to FIGS. 29 and 30 , LSV measurement according to the number of cycles was performed for the CuPS electrode structure according to Experimental Example 1 and the commercially available RuO _{2 electrode using 0.1M KOH and under the condition of 1600 rpm.} In addition, the CuPS electrode structure and the RuO ₂ electrode according to Experimental Example 1 were measured by a chronoamperometric method under 1.5V conditions, and the Faraday efficiency of the CuPS electrode according to Experimental Example 1 was measured. For the electrode structure according to Experimental Example 1, CuP _0.5 S _0.5 was used.

As can be seen in FIGS. 29 and 30 , it can be seen that the electrode structure according to Experimental Example 1 is stably driven without substantial change even after 30,000 cycles are performed. In addition, it can be seen that it is stably operated without substantial change for about 500 hours, and has a Faraday efficiency of about 99% or more.

_{On the other hand, in the case of the RuO 2} electrode, it can be seen that the overpotential rapidly increases as the cycle is performed, and the current density value rapidly decreases, and a loss of 85% or more occurs after 24 hours.

In conclusion, it can be seen that the CuPS electrode structure according to Experimental Example 1 has a high OER characteristic as well as _{a longer lifespan compared to a commercialized RuO 2 electrode.}

31 is a graph for explaining the bifunctional oxygen characteristics of the electrode structure, the Pt/C electrode, the RuO ₂ electrode, and the carbon fiber according to Experimental Examples 1 to 4 of the present application, and FIG. 32 is the present application It is a graph comparing the bifunctional oxygen properties of the electrode structure according to Experimental Example 1 and other electrodes reported to date.

31 and 32 , the ORR and OER characteristics of the electrode structures, the Pt/C electrode, the RuO ₂ electrode, and the carbon fiber according to Experimental Examples 1 to 4 were compared. For the electrode structures according to Experimental Example 1 and Experimental Example 2, CuP _0.5 S _0.5 was used. The reversible amount of oxygen functional reaction is determined by the difference (ΔE) of the overpotentials of ORR and OER, and the smaller the difference, the higher the reversibility.

As shown in FIG. 31 , in the case of the electrode structure of Experimental Example 1, the difference in the overpotential of ORR and OER is 0.59V, and it can be confirmed that it has excellent reversibility compared to the _{commercially available Pt/C electrode and the RuO 2 electrode.} .

In addition, as shown in FIG. 32 , in the case of the electrode structure of Experimental Example 1, the difference in overpotential between ORR and OER is the smallest compared to other electrodes reported to date, and excellent reversibility for OER and ORR reactions It can be confirmed that has

33 is an LSV graph for explaining the HER characteristics of Experimental Examples 1 to 4, Pt/C electrodes, and carbon fibers of the present application, and FIG. 34 is an electrode structure and Pt/C according to Experimental Example 1 of the present application. It is a chronoamperometric measurement graph for explaining the HER characteristics of the electrode, and FIG. 35 is a Tafel profile for explaining the HER characteristics of Experimental Examples 1 to 4, Pt/C electrode, and carbon fiber of the present application.

33 to 35 , LSV measurements of the electrode structures, carbon fibers, and Pt/C electrodes according to Experimental Examples 1 to 4 were performed, and Tafel values were shown. In addition, the electrode structure and the Pt/C electrode according to Experimental Example 1 were measured by a chronoamperometric method. For the electrode structures according to Experimental Example 1 and Experimental Example 2, CuP _0.5 S _0.5 was used.

33 to 35 , the electrode structure of Experimental Example 1, the Pt/C electrode, the electrode structure of Experimental Example 2, the electrode structure of Experimental Example 4, the electrode structure of Experimental Example 3, and the HER characteristics in the order of carbon fiber It can be seen that this is excellent.

In particular, it can be confirmed that the CuPS electrode structure according to Experimental Example 1 has higher HER characteristics compared to the commercialized Pt/C electrode. In particular, the Tafel value of the electrode structure of Experimental Example 1 is 20mVdec ^{-1 , which is lower than the Tafel value (30mVdec -1} ) of the Pt/C electrode, which indicates that the HER process of the electrode structure of Experimental Example 1 is performed by the Volmer-Tafel mechanism. it means.

36 is an LSV graph according to the number of cycles for explaining the HER characteristics of the electrode structure and the Pt/C electrode according to Experimental Example 1 of the present application.

Referring to FIG. 36 , LSV measurement was performed according to the number of cycles for the CuPS electrode structure and the Pt/C electrode according to Experimental Example 1.

As can be seen from FIG. 36 , in the case of the Pt/C electrode, it can be seen that the overpotential is greatly increased after 20,000 cycles, and thus the HER characteristic is rapidly deteriorated. On the other hand, it can be seen that the electrode structure according to Experimental Example 1 is stably driven without substantial change even after 30,000 cycles are performed.

In conclusion, it can be seen that the CuPS electrode structure according to Experimental Example 1 has a high HER characteristic as well as a longer lifespan compared to a commercialized Pt/C electrode.

37 is a graph comparing the HER characteristics of the electrode structure according to Experimental Example 1 of the present application and another electrode reported to date.

Referring to FIG. 37 , in the case of the electrode structure (CuP _0.5 S _0.5 ) according to Experimental Example 1, it can be seen that the overpotential value is small compared to other electrodes reported to date, and accordingly, in Experimental Example 1 It can be confirmed that the electrode structure according to the present invention can implement high HER characteristics without the use of expensive precious metals.

38 is an LSV graph for explaining ORR characteristics in an acidic environment of an electrode structure and a Pt/C electrode according to Experimental Example 1 of the present application, and FIG. 39 is an electrode structure and a Pt/C electrode according to Experimental Example 1 of the present application is an LSV graph for explaining HER characteristics in an acidic environment of

Referring to FIGS. 38 and 39 , _{using 0.1M HClO 4} , LSV measurements of the electrode structure and the Pt/C electrode according to Experimental Example 1 were performed to confirm the ORR characteristics. In addition, the HER characteristics of the electrode structure according to Experimental Example 1 and other electrodes reported to date in a _{0.5MH 2} SO _{4 environment were compared.} For the electrode structure according to Experimental Example 1, CuP _0.5 S _0.5 was used.

As can be seen from FIG. 38 , the electrode structure according to Experimental Example 1 was stably driven even in an acidic environment, and the actual ORR characteristics did not change even after 10,000 cycles were performed. On the other hand, it can be seen that the ORR characteristics of the Pt/C electrode were deteriorated due to a sharp increase in overpotential after 10,000 cycles were performed in an acidic environment.

In addition, as can be seen in FIG. 39, the electrode structure of Experimental Example 1 slightly increased overpotential after 20,000 cycles, and thus the HER characteristics were stably maintained even in an acidic environment, but in the case of the Pt/C electrode, 20,000 cycles were performed. After that, it can be seen that the overpotential is significantly increased and the HER characteristics are deteriorated.

In addition, as can be seen in FIG. 40 , it can be confirmed that the electrode structure of Experimental Example 1 can maintain high HER characteristics even in an acidic environment compared to other electrodes reported to date.

41 is a mass activity graph for comparing ORR, OER, and HER characteristics of _{electrode structures, Pt/C electrodes, and RuO 2} electrodes according to Experimental Examples 1 and 2 of the present application.

Referring to FIG. 41 , mass activity was calculated in ORR, OER, and HER of the electrode structures, Pt/C electrodes, and RuO _{2 electrodes according to Experimental Examples 1 and 2 .} For the electrode structures according to Experimental Examples 1 and 2, CuP _0.5 S _0.5 was used.

As shown in FIG. 41 , it can be seen that the electrode structures according to Experimental Example 1 and Experimental Example 2 have higher mass activity in _{ORR, OER, and HER compared to the Pt/C electrode and the RuO 2 electrode.}

In particular, in the case of the electrode structure according to Experimental Example 1, it can be seen that the mass activity value is maintained without substantial change even after 30,000 cycles are performed.

In conclusion, it can be seen that the electrode structures according to Experimental Examples 1 and 2 have higher ORR, OER, and HER characteristics compared to _{commercially available Pt/C and RuO 2 .}

42 is an in-situ XRD measurement graph of the electrode structure according to Experimental Example 1 in the charging/discharging state of the secondary battery according to Experimental Example 1 of the present application, and FIG. 43 is a secondary battery according to Experimental Example 1 of the present application. It is an HRTEM photograph of the electrode structure according to Experimental Example 1 in the charging/discharging state of the battery.

42 and 43 , an in situ XRD measurement of the electrode structure according to Experimental Example 1 was performed in the charging/discharging state of the secondary battery according to Experimental Example 1, along with a galvanostatic charge/discharge profile and Experimental Example 1 The volume change of the unit cell of the electrode structure is shown. In addition, an HRTEM photograph of the electrode structure according to Experimental Example 1 was taken in the charging/discharging state of the secondary battery according to Experimental Example 1.

As can be seen in FIGS. 42 and 43 , in the electrode structure of Experimental Example 1, a peak is observed within a range of 2θ values of 18.5° to 19.5°, and as charging proceeds in a discharged state, a 2θ value corresponding to the peak It moves to the left and decreases, and it can be seen that the peak is divided into two. In addition, it can be seen that the lattice spacing increases from 0.466 nm to 0.478 nm when buffered at 2.2 V, and the volume of the unit cell increases ^{from 287.2 Å 3} to 294.6 Å ³ . That is, it can be seen that a solid-solution reaction occurs while the electrode structure of Experimental Example 1 maintains an orthorhombic crystal structure during charging and discharging.

44 is a HRTEM photograph of the electrode structure according to Experimental Example 1 in the charging/discharging state of the secondary battery according to Experimental Example 1 of the present application.

Referring to FIG. 44 , in the charging and discharging states of the secondary battery according to Experimental Example 1, an HRTEM photograph of the electrode structure according to Experimental Example 1 was taken. As the electrode structure according to Experimental Example 1, CuP _0.1 S _0.9 , CuP _0.5 S _0.5 , and CuP _0.9 S _0.1 were used. 58 a, b, c are _{HRTEM pictures of CuP 0.1} S _0.9 , d, e, f of _{FIG. 58 are HRTEM pictures of CuP 0.5} S _0.5 , g, h, i of CuP _0.9 S _0.1 This is an HRTEM picture.

As can be seen from FIG. 44 , in the case of CuP _0.1 S _0.9 and CuP _0.9 S _{0.1 ,} the redox band of Cu is higher than the S 3p band, and the oxidized sulfur may be unstable. For this reason, as shown in FIG. 58 , it can be confirmed that the grid spacing is not reversibly recovered even when charging and discharging are performed. On the other hand, in _{the case of CuP 0.5} S _0.5, the lattice spacing before charging is 0.466 nm, the lattice spacing after charging is 0.478 nm, the lattice spacing after discharging is 0.466 nm, and after charging and discharging, the lattice spacing is reversible. recovery can be seen.

45 is a graph evaluating OER, ORR, and HER characteristics according to crystal planes in the electrode structure according to Experimental Example 1 of the present application.

Referring to FIG. 45 , according to the crystal plane of the CuPS electrode structure according to Experimental Example 1, overpotentials for OER and ORR reactions (bifunctional activity) and overpotentials for HER reactions were calculated using discrete Fourier transforms.

As can be seen from FIG. 45 , it can be confirmed that the overpotential value of the (101) crystal plane is the lowest, and accordingly, the ORR, OER, and HER characteristics of the electrode structure in which the (101) crystal plane is developed according to the embodiment of the present application are improvement can be seen.

In conclusion, it can be seen that manufacturing the electrode structure having a (101) crystal plane developed and using it as a positive electrode of a zinc-air battery is an efficient method for improving the charge/discharge characteristics of a zinc-air battery.

46 is a graph evaluating ORR, OER, and HER characteristics according to the composition ratio of P and S of the electrode structure according to Experimental Example 1 of the present application.

Referring to FIG. 46 , in the CuPS electrode structure according to Experimental Example 1, ORR, OER, and HER characteristics according to the composition ratio of P and S were measured and shown.

As can be seen in FIG. 46 , in the CuPS electrode structure, when the composition ratio of P is greater than 0.3 and less than 0.7, and the composition ratio of S is less than 0.7 and greater than 0.3, it can be confirmed that ORR, OER, and HER characteristics are excellent. In other words, in the CuPS electrode structure, it can be confirmed that controlling the composition ratio of P to be greater than 0.3 and less than 0.7 and the composition ratio of S to be less than 0.7 and greater than 0.3 is an efficient method to improve ORR, OER, and HER characteristics. .

47 is Cu 2p, P 2p, and S 2p XPS spectra according to the composition ratio of P and S of the electrode structure according to Experimental Example 1 of the present application.

Referring to FIG. 47 , in the CuPS electrode structure according to Experimental Example 1, Cu 2p, P 2p, and S 2p XPS measurements were performed according to the composition ratio of P and S, and the composition ratio was calculated as shown in Table 4 below. .

CP _x S _1-x to x value Cu (at.%) P (at.%) S (at.%) 0.1 49.56 10.21 40.23 0.3 49.19 19.93 30.88 0.5 48.92 24.89 26.19 0.7 49.16 30.48 20.36 0.9 48.86 40.99 10.15

48 is a graph evaluating ORR, OER, and HER characteristics according to the composition ratio of Cu and S of the electrode structure according to Experimental Example 3 of the present application, and FIG. 49 is Cu of the electrode structure according to Experimental Example 3 of the present application and FIG. It is an XRD graph according to the composition ratio of S, and FIG. 50 is a graph showing lattice parameters according to the composition ratio of Cu and S of the electrode structure according to Experimental Example 3 of the present application.

48 and 49 , in the CuS electrode structure according to Experimental Example 3, ORR, OER, and HER characteristics were measured according to the ratio of Cu and S, XRD measurement was performed, and lattice parameter values were calculated.

As can be seen in FIGS. 48 and 49, in the case of the CuS electrode structure according to Experimental Example 3, when the composition ratio of S is 0.35 or more and 0.6 or less, the CuS electrode structure has a cobelite crystalline phase, and improved ORR, OER, and HER characteristics You can check what you have. In addition, when the composition ratio of S exceeds 0.6, _{phases such as CuS, Cu 2} S, remaining S, and CuS ₂ are observed to be mixed, and when the composition ratio of S is less than 0.35, _{it can be confirmed that Cu 2} S and chalcocite phases appear. have.

In addition, as can be seen from FIG. 50 , when the composition ratio of S is increased, the lattice parameter of the unit cell of the electrode structure of Experimental Example 3 increases, thereby increasing the volume of the unit cell, and thus, as shown in FIG. As shown, it can be seen that the peak value shifts.

51 is a graph comparing the discharge voltage according to the current density of the zinc-air battery including the electrode structure according to Experimental Example 1 of the present application.

Referring to FIG. 51 _{, a zinc-air battery according to a comparative example was prepared using a Pt/C and RuO 2} positive electrode, an A201 (Tokuyama) electrolyte, and a zinc negative electrode, and a zinc-air battery including the electrode structure according to Experimental Example 1 and Discharge voltage according to 5-200mAcm ^-2 current density was measured.

As can be seen from FIG. 51 , it can be seen that the discharge voltage of the zinc-air battery including the CuPS electrode structure according to Experimental Example 1 is remarkably high. In particular, as the current density increases, Pt/C and RuO according to Comparative Example _It can be seen that the discharge voltage of the zinc-air battery including the 2 positive electrode is significantly lowered. On the other hand, it can be seen that, in the zinc-air battery including the CuPS electrode structure according to Experimental Example 1, the discharge voltage is not significantly lowered compared to the zinc-air battery according to the Comparative Example even under a high current density condition.

52 is a graph for explaining the charge/discharge capacity of the zinc-air battery according to Experimental Example 1 of the present application.

Referring to FIG. 52 , the capacity according to the current density of the zinc-air battery according to the above-described comparative example and the zinc-air battery according to Experimental Example 1 was measured.

As can be seen in FIG. 52, the zinc-air battery according to Experimental Example 1 including the CuPS electrode structure was not only ^{under the 25mAcm -2} condition, but ^{also under the 50mAcm-2} condition, Pt/C and RuO ₂ Zinc according to a comparative example using as a positive electrode It can be seen that the air battery has a ^{higher capacity value than the 25mAcm -2 condition.}

53 is a graph of measuring voltage values according to the number of times of charging and discharging of the zinc-air battery according to Experimental Example 1 of the present application.

Referring to FIG. 53 , voltage values according to the number of charging and discharging times were measured for the zinc-air battery according to Experimental Example 1 ^{under 50 mAcm -2} conditions and 25 mA ^{-2 conditions.}

As can be seen from FIG. 53 , it can be confirmed that the battery is stably driven for about 600 times of charging and discharging. That is, it can be confirmed that the CuPS electrode structure manufactured according to the above-described embodiment of the present application can be stably used as a positive electrode together with a solid electrolyte.

As mentioned above, although the present invention has been described in detail using preferred embodiments, the scope of the present invention is not limited to specific embodiments and should be construed according to the appended claims. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

Claims (14)

In the electrode structure for a positive electrode of a zinc-air battery,
The electrode structure, comprising a membrane formed of a compound of copper, phosphorus and sulfur and a plurality of fibrillated fibers forming a network, the electrode structure for a positive electrode of a zinc-air battery.
According to claim 1,
The plurality of fibers formed of a compound of copper, phosphorus and sulfur,
a plurality of stems; and
An electrode structure for a positive electrode of a zinc-air battery comprising a plurality of branches branched from the plurality of stems.
3. The method of claim 2,
The plurality of stems and the plurality of branches are electrode structures for a positive electrode of a zinc-air battery comprising those manufactured in different processes.
According to claim 1,
The membrane of the electrode structure has a sponge structure, the electrode structure for a positive electrode of a zinc-air battery comprising a flexible one.
According to claim 1,
Accordingly, in the state of charge and discharge of the zinc-air battery,
Electrode structure for a positive electrode of a zinc-air battery comprising the reversible increase or decrease in the lattice spacing of the membrane of the electrode structure observed by HRTEM.
In the electrode structure for a positive electrode of a zinc-air battery,
The electrode structure is formed of a compound of copper and sulfur and includes a membrane in which a plurality of fibrillated fibers form a network, the electrode structure for a positive electrode of a zinc-air battery.
7. The method of claim 6,
The compound of copper and sulfur is an electrode structure for a positive electrode of a zinc-air battery comprising that represented by the following <Formula 1>.
<Formula 1>
CuS _x
(0.35≤x≤0.6)
A positive electrode comprising the electrode structure according to claim 1 or 6;
a zinc anode on the anode electrode; and
A zinc-air battery comprising an electrolyte between the positive electrode and the zinc negative electrode.
Preparing a first precursor having a chalcogen element, a second precursor having phosphorus, and a third precursor having a transition metal;
mixing the first precursor, the second precursor, and the third precursor, and adding a first reducing agent to prepare a mixture;
co-precipitating the mixture to prepare an intermediate product having a plurality of stems; and
In a method of adding a second reducing agent to the intermediate product and heat-treating under pressure, a plurality of fibrillated fibers comprising the transition metal, the chalcogen element, and phosphorus by branching a plurality of branches from the plurality of stems A method of manufacturing an electrode structure comprising the step of manufacturing.
10. The method of claim 9,
The first precursor is dithiooxamide, Dithiobiuret, Dithiouracil, Acetylthiourea, Thiourea, N-methylthiourea, Bis(phenylthio)methane, 2-Imino-4-thiobiuret, N,N′-Dimethylthiourea, Ammonium sulfide, Methyl methanesulfonate, Sulfur powder, At least one of sulphates, N,N-Dimethylthioformamide, or Davy Reagent methyl,
The second precursor is tetradecylphosphonic acid, ifosfamide, Octadecylphosphonic acid, Hexylphosphonic acid, Trioctylphosphine, Phosphoric acid, Triphenylphosphine, Ammonium Phosphide, pyrophosphates, Davy Reagent methyl, Cyclophosphamide monohydrate, Phosphorus trichloride, Phosphorus trichloride, methyl, Cyclophosphamide monohydrate, Phosphorus trichloride, Phosphorus trichloride. , or at least one of Phosphorus pentasulfide,
The third precursor is copper chloride, copper(II) sulfate, copper(II) nitrate, copper selenide, copper oxychloride, cupric acetate, copper carbonate, copper thiocyanate, copper sulfide, copper hydroxide, copper naphthenate, or copper(II) A method of manufacturing an electrode structure comprising at least one of phosphate.
10. The method of claim 9,
With the second reducing agent, a method of manufacturing an electrode structure comprising further adding a chalcogen element source having a chalcogen element.
10. The method of claim 9,
In the cooled state, the method of manufacturing an electrode structure comprising adding the second reducing agent.
10. The method of claim 9,
The first reducing agent includes at least one of Ammonium hydroxide, Ammonium chloride, or Tetramethylammonium hydroxide,
The second reducing agent is, Triton X-165, Triton X-102, Triton X-45, Triton X-114 Triton X-405, Triton X-101, Trimesic acid, Diamide, Peroxynitrite, formaldehyde, Thimerosal, or chloramine-T A method of manufacturing an electrode structure comprising at least one of.
10. The method of claim 9,
The chalcogen element is sulfur,
A method of manufacturing an electrode structure comprising that the transition metal is copper.

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