KR101903652B1 - Method of manufacturing an electrode material using infiltration method - Google Patents

Abstract

Provided is a catalyst body for metal air cells having high electrical conductivity and high activities. According to one embodiment of the present invention, a method for producing an electrode material comprises the following steps: providing a powdery shape structure; impregnating a metal precursor solution in the powdery shape structure; and sintering the impregnated powdery shape structure to form metal oxide nanoparticles on a surface of the powdery shape structure.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an electrode material using an impregnation method,

TECHNICAL FIELD The present invention relates to an electrode material, and more particularly, to a method for manufacturing an electrode material using an impregnation method, a metal air cell including the electrode material produced using the electrode material, a solid oxide fuel cell, It is about the water electrolytic cell.

In recent years, solid oxide fuel cells and metal air cells have been actively studied as secondary replacements that can replace conventional lithium ion batteries.

A solid oxide fuel cell (SOFC) is a highly efficient, environmentally friendly electrochemical power generation technology that directly converts the chemical energy of a fuel gas into electrical energy. Since all components are solid, SOFC has a simple structure, relatively low cost, and is free from electrolyte loss and replacement and corrosion problems compared to other fuel cells. The metal air cell is a secondary battery technology which is much higher in energy density than the lithium ion battery having the highest energy density among currently used secondary batteries and is actively studied as a next generation energy source for electric vehicles and the like.

The solid oxide fuel cell and the metal air cell are required to have a noble metal catalyst such as platinum due to the slow oxygen reduction reaction, so that the manufacturing cost is high. In addition, Li ₂ CO ₃ compounds formed by side reactions of the cathode may deteriorate battery performance and shorten battery life. Therefore, it is required that the current collector composed of a carbon body or the like does not react with lithium ions or the like. Therefore, development of a cathode having high electrical conductivity at room temperature and high activity and high stability is required.

Further, the anode used as the catalyst has a problem that the anode electrode is rapidly destroyed by carbon deposition. Also, it is very important that the anode electrode should have a stable structure in a hydrogen environment, and at the same time maintain an electric conductivity higher than a certain value. In such a hydrogen environment, there is a fear that the performance of the anode may deteriorate over a long period of use. Therefore, development of an anode having excellent thermal and chemical stability and high electrical conductivity is required.

Korean Patent Publication No. 10-2003-0084903

SUMMARY OF THE INVENTION The present invention provides an electrode material having high electrical conductivity, high activity, and high stability, and a method for producing the electrode material.

Another object of the present invention is to provide a metal air battery including the electrode material.

Another object of the present invention is to provide a solid oxide fuel cell including the electrode material.

Another object of the present invention is to provide a solid oxide electrolytic cell including the electrode material.

However, these problems are illustrative, and the technical idea of the present invention is not limited thereto.

According to an aspect of the present invention, there is provided a method of manufacturing an electrode material, the method including: providing a powdered structure; Impregnating the powdery structure with a metal precursor solution; And sintering the impregnated powdery structure to form metal oxide nanoparticles on the surface of the powdery structure.

In some embodiments of the present invention, the metal precursor solution may comprise a metal nitride.

In some embodiments of the present invention, the metal nitride is _{Co (NO 3) 2 · 6H} 2 O, Nd (NO 3) 3 · 6H 2 O, Ba (NO 3) 2, and Sr (NO ₃₎ of the ₂ And may include at least any one of them.

In some embodiments of the present invention, the metal precursor solution may comprise an alcoholic solution as a solvent.

In some embodiments of the present invention, the sintering may be performed at a temperature in the range of 400 ° C to 500 ° C.

In some embodiments of the present invention, the metal oxide nanoparticles may range from 10 wt% to 20 wt% based on the total weight.

In some embodiments of the present invention, the powdery structure may comprise a perovskite crystal structure.

In some embodiments of the present invention, the perovskite crystal structure may comprise a compound of the following formula (1).

≪ Formula 1 >

RETO _{5 + δ}

Wherein R comprises one or more elements selected from rare earth elements or lanthanides, E comprises one or more elements selected from the group of the alkaline earth metals, and T is selected from the group consisting of one selected from transition metals Or more, O is oxygen, and? Is a positive number of 0 or 1 or less, and is a value that makes the compound of formula (1) electrically neutral.

In some embodiments of the present invention, R is selected from the group consisting of yttrium (Y), neodymium (Nd), praseodymium (Pr), scandium (Sc), samarium (Sm), gadolinium (Gd) ), Terbium (Tb), erbium (Er), or mixtures thereof.

In some embodiments of the present invention, E is at least one selected from beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) And mixtures thereof.

In some embodiments of the present invention, T is at least one element selected from the group consisting of Mn, Co, Fe, Cu, Cr, Ni, Ti), niobium (Nb), or mixtures thereof.

In some embodiments of the present invention, the perovskite crystal structure may include a compound represented by the following general formula (2).

(2)

REE'TO _{5 + δ}

Wherein R is one or more elements selected from a rare earth group or a lanthanide group, E and E 'are different elements selected from an alkaline earth metal group, and T is one or more selected from transition metals And O is oxygen, and the delta is a positive number of 0 or 1 or less, and the compound of Formula 2 is a value that is electrically neutral.

In some embodiments of the present invention, the perovskite crystal structure may comprise a compound of the following formula (3).

(3)

RETT'O _{5 + δ}

In Formula 3, R may include one or more elements selected from the Lanthanon family, and E may include one or more elements selected from the group of the alkaline earth metals, and T and T ' And O may be oxygen, and the value of? Is a positive number of 0 or 1 or less, and the value of the compound of the above formula (3) is an electrical neutrality.

In some embodiments of the present invention, the perovskite crystal structure may comprise a compound of the following formula (4).

≪ Formula 4 >

REE'TT'O _{5 + δ}

In Formula 4, R may include one or more elements selected from lanthanides, E and E 'are different elements selected from an alkaline earth metal group, and T and T' are selected from transition metals May contain different elements, O is oxygen, and? Is a positive number of 0 or 1 or less, which is a value that makes the compound of Formula 4 electrically neutral.

In some embodiments of the present invention, the perovskite crystal structure comprises NdBaCo ₂ O _{5 + δ} , PrBaCo ₂ O _{5 + δ} , SmBaCo ₂ O _{5 + δ} , GdBaCo ₂ O _{5 + δ} , NdSrCo ₂ O _{5 + δ, PrSrCo 2 O 5 +} δ, SmSrCo 2 O 5 + δ, GdSrCo 2 O 5 + δ, NdBa 1 - x Sr x Co 2 O 5 + δ, PrBa 1 - x Sr x Co 2 O 5 + δ, _{SmBa 1 - x Sr x Co 2} O 5 + δ, GdBa 1-x Sr x Co 2 O 5 + δ, NdBaMn 2 - y Co y O 5 + δ, PrBaMn 2 - y Co y O 5 + δ, SmBaMn 2 _{- y} Co _y O _{5 +} ?, GdBaMn _{2 -y} Co _y O _{5 +} ?, NdBa _{1 - x} Sr _x Mn _{2 - y} Co _y O _{5 + ?} , PrBa _{1 - x} Sr _x Mn _{2 - y} Co _y O _{5 + δ, SmBa 1 - x} Sr x Mn 2 - y Co y O 5 + δ, and GdBa _1-x Sr _x Mn _2-y Co _y O _{5 + δ} (where x is a number less than 0 1, and , and y is a number of more than 0 and less than 2).

In some embodiments of the present invention, the perovskite crystal structure may comprise a single layer perovskite crystal structure material or a double layer perovskite crystal structure material.

According to an aspect of the present invention, there is provided an electrode material comprising: a powder-like structure; And metal oxide nanoparticles formed on the surface of the powdery structure.

According to an aspect of the present invention, there is provided a metal air cell comprising: a cathode; An anode facing the cathode; And an electrolyte disposed between the cathode and the anode, wherein at least one of the cathode and the anode is composed of the electrode material described above.

According to an aspect of the present invention, there is provided a solid oxide fuel cell comprising: a cathode; An anode facing the cathode; And an electrolyte disposed between the cathode and the anode, wherein at least one of the cathode and the anode is composed of the electrode material described above.

According to an aspect of the present invention, there is provided a solid oxide water receiving cell including a cathode for discharging hydrogen gas formed by decomposition of water; An anode disposed facing the cathode and discharging the oxygen gas formed by decomposition of the water; And an electrolyte disposed between the anode and the cathode, wherein at least one of the cathode and the anode is composed of the electrode material described above.

According to the technical idea of the present invention, an electrode material is formed by impregnation in a powder forming structure. Conventionally, a method of forming a nano-surface structure that enlarges the surface area or forming a mixed catalyst using two or more materials has been used to form a deformation vessel catalyst structure to be applied to an electrode material. However, both of these methods have produced catalysts through relatively expensive and complicated processes such as hydrothermal methods and CVD. However, the impregnation method according to the technical idea of the present invention can be formed by a simple process of impregnation process and sintering process and metal oxide nanoparticles are formed on the surface of the powdery structure to be used as a catalyst by using relatively simple equipment Whereby an electrode material including a mixed catalyst can be produced. These electrode materials showed an improved effect in both the oxygen reduction reaction and the oxygen generation reaction, thereby providing a function as a deactivation vessel catalyst structure, increasing the activity of the battery, increasing the stability, Can be saved.

The electrode material can be used as an electrode material of a cathode or an anode, such as a metal air cell, a solid oxide fuel cell, and a solid oxide electrolytic cell. Specifically, the electrode material can be used as an electrode substrate constituting a cathode electrode or an anode electrode, and can also be used as a catalyst body in place of a noble metal catalyst.

1 is a flow chart showing a method of manufacturing an electrode material according to an embodiment of the present invention.
2 is a schematic view showing a perovskite crystal structure constituting an electrode material according to an embodiment of the present invention.
3 is a schematic diagram showing a case where some atoms are substituted in a perovskite crystal structure constituting an electrode material according to an embodiment of the present invention.
FIGS. 4 and 5 are SEM micrographs of an electrode material manufactured according to an embodiment of the present invention.
6 is a graph showing an oxygen reduction reaction of an electrode material manufactured according to an embodiment of the present invention.
7 is a graph showing an oxygen generating reaction of an electrode material manufactured according to an embodiment of the present invention.
8 is a schematic view illustrating a metal air cell including an electrode formed of an electrode material according to an embodiment of the present invention.
9 is a schematic diagram of a solid oxide fuel cell including an electrode formed of an electrode material, according to an embodiment of the present invention.
10 is a view schematically showing a solid oxide water-receiving cell including an electrode formed of an electrode material, according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. The scope of technical thought is not limited to the following examples. Rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The same reference numerals denote the same elements at all times. Further, various elements and regions in the drawings are schematically drawn. Accordingly, the technical spirit of the present invention is not limited by the relative size or spacing depicted in the accompanying drawings.

In this specification, the electrode material may refer to an electrode material used for a cathode or an anode, such as a metal air cell, a solid oxide fuel cell, and a solid oxide electrolytic cell. The electrode material may include a cathode electrode or an electrode substrate of the anode electrode and a catalyst body added to the electrode substrate.

1 is a flowchart showing a method (S100) for manufacturing an electrode material according to an embodiment of the present invention.

Referring to FIG. 1, a method (S100) for manufacturing an electrode material includes the steps of: (S110) providing a powdery structure; Impregnating the powdery structure with a metal precursor solution (S120); And sintering the impregnated powdery structure to form metal oxide nanoparticles on the surface of the powdery structure (S130).

The electrode material according to the technical idea of the present invention includes a powdered structure; And metal oxide nanoparticles formed on the surface of the powdery structure. The powdery structure may include a perovskite crystal structure. The perovskite crystal structure will be described in detail below.

The metal precursor solution may include a metal nitride. The metal nitride _{solution, Co (NO 3) 2 ·} 6H 2 O, Nd (NO 3) 3 · 6H 2 O, Ba (NO 3) 2, and Sr (NO ₃₎ may comprise at least one of ₂ have. The metal precursor solution may include an alcohol-based solution as a solvent, and may include at least one of methanol, ethanol, and isopropyl alcohol, for example. For example, the metal precursor solution may be formed by dissolving cobalt nitride (Co (NO ₃ ) ₂ .6H ₂ O) in ethanol.

By impregnating the powdered structure with the metal precursor solution, the metal precursor solution is coated or wetted on the surface of the powdered structure. Such impregnation may be performed by immersing the powdery structure in the metal precursor solution or spraying the metal precursor solution onto the powdery structure.

In the case of sintering the impregnated powdery structure, the sintering temperature may be, for example, carried out at a temperature in the range of 400 ° C to 500 ° C, and the sintering time may be in the range of 1 minute to 24 hours.

The metal oxide nanoparticles may have a weight fraction of, for example, 10 wt% to 20 wt% with respect to the total weight (the sum of the weight of the powder structural body and the weight of the metal oxide nanoparticles). In order to form the metal oxide nanoparticles having such a weight fraction, the impregnation process and the sintering process may be repeatedly performed.

The method of manufacturing the electrode material according to the technical idea of the present invention is advantageous in that the sintering process of the powdered structure and the sintering process of the metal oxide nanoparticles are separated and the respective particle sizes can be separately controlled. Further, by using the powdery structure, the particle size, the fraction of the nanoparticles of the metal oxide, and the like can be freely controlled.

The electrode material may comprise a variety of powdered structures and may include, for example, a perovskite crystal structure. The perovskite crystal structure may include a single layer perovskite crystal structure or a double layer perovskite crystal structure as an oxide material having excellent conductivity. Hereinafter, the perovskite crystal structure will be described.

2 is a schematic view showing a perovskite crystal structure constituting an electrode material according to an embodiment of the present invention.

Referring to FIG. 2, a bilayer perovskite crystal structure material is shown. The perovskite crystal structure material can be largely divided into a single perovskite crystal structure material and a double layer perovskite crystal structure material.

A simple perovskite crystal structure material may have the formula ABO ₃ . The single perovskite crystal structure may include elements having relatively large ionic radii in the A-site at the corner of the cubic lattice, CN, Coordination number). For example, a rare earth element, an alkaline rare earth element, and an alkaline element may be located in the A-site. The B-site, which is the body center of the cubic lattice, may contain elements having relatively small ionic radii, and may have six coordination numbers by oxygen ions. For example, cobalt (Co), iron (Fe), and the like and a transition metal may be located in the B-site. Oxygen ions may be located at each face center of the cubic lattice. Such a single perovskite structure can generally result in structural displacements when other materials are substituted on the A-site, and it is often the case that the nearest oxygen ions in the octahedron of BO ₆ consisting of six) it may cause structural variations.

For example, upon reduction in a hydrogen atmosphere, the single perovskite structure is transformed into a double layer perovskite structure. This double-perovskite structure can accelerate oxygen ion movement and improve thermal and chemical stability.

As shown in FIG. 2, the bilayer perovskite crystal structure is a crystal lattice structure in which two or more elements are regularly arranged on the A-site, and may have a formula of AA'BO _{5 + delta} . Such a double layer perovskite crystal structure material may have an oxygen vacancy population to facilitate the movement of ions, thereby imparting improved ionic conductivity to the cathode.

3 is a schematic diagram showing a case where some atoms are substituted in a perovskite crystal structure constituting an electrode material according to an embodiment of the present invention.

Referring to FIG. 3, the double layer perovskite structure is a crystal lattice structure in which two or more elements are regularly arranged on the A-site, and may have a chemical formula of, for example, AA'B ₂ O _{5 +} . Specifically, a lanthanide compound having a bilayer perovskite structure can be basically repeated with the lamination permutation of [BO ₂ ] - [AO] - [BO ₂ ] - [A'O] along the c axis. For example, B may be manganese (Mn), A may be a lanthanide group including praseodymium (Pr), and the A 'may be barium (Ba). Further, the manganese may be substituted with another transition metal, for example, cobalt. When such substitution occurs, the double layer perovskite structure may have the formula AA'B _{2 - x} B ' _x O _{5 + δ} .

Reduction in a hydrogen atmosphere results in a change from a single perovskite crystal structure material to a double layer perovskite crystal structure material. Such double-perovskite crystal structure can accelerate oxygen ion movement and improve thermal and chemical stability. In addition, an electrode material exhibiting excellent electrical conductivity in a hydrogen atmosphere and thermal and chemical stability compared to conventional electrode materials can be realized.

The perovskite crystal structure material constituting the electrode according to an embodiment of the present invention may include a compound represented by the following formula (1).

≪ Formula 1 >

RETO _{5 + δ}

Wherein R comprises one or more elements selected from rare earth elements or lanthanides, E comprises one or more elements selected from the group of the alkaline earth metals, and T is selected from the group consisting of one selected from transition metals Or more, O is oxygen, and? Is a positive number of 0 or 1 or less, and is a value that makes the compound of formula (1) electrically neutral. The above 隆 represents interstitial oxygen in the following double layer perovskite structure and the value of 隆 can be determined according to a specific crystal structure.

In the above formula (1), R may include a lanthanide element, for example, yttrium (Y), neodymium (Nd), praseodymium (Pr), scandium (Sc), samarium (Sm) (Gd), europium (Eu), terbium (Tb), erbium (Er), or mixtures thereof.

In the above Formula 1, E may include, for example, an alkaline earth metal such as beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) Rhodium (Ra), or mixtures thereof.

In the above Formula 1, the T may include, for example, a transition metal, and may include, for example, Mn, Co, Fe, Cu, Ni), titanium (Ti), niobium (Nb), or mixtures thereof.

In addition, the compound of formula (1) may contain various compounds according to the above R. For example, the compound of Formula 1 may be selected from the group consisting of NdBaCo ₂ O _{5 + δ} , PrBaCo ₂ O _{5 + δ} , SmBaCo ₂ O _{5 + δ} , GdBaCo ₂ O _{5 + δ} , NdSrCo ₂ O _{5 + δ} , PrSrCo ₂ O _{5 + δ,} SmSrCo may be a compound represented by the ₂ O _{5 + δ,} or GdSrCo ₂ O _{5 + δ.} It is also included in the technical idea of the present invention that the above compound contains another alkaline earth metal instead of barium (Ba) or strontium (Sr), or contains other transition metal instead of cobalt (Co).

The compound of Formula 1 may have a single layer perovskite crystal structure or a double layer perovskite crystal structure.

According to an embodiment of the present invention, the perovskite crystal structure material constituting the electrode may include a compound represented by the following formula (2).

(2)

REE'TO _{5 + δ}

Wherein R is one or more elements selected from a rare earth group or a lanthanide group, E and E 'are different elements selected from an alkaline earth metal group, and T is one or more selected from transition metals And O is oxygen, and the delta is a positive number of 0 or 1 or less, and the compound of Formula 2 is a value that is electrically neutral.

In Formula 2, E 'may be a substance that substitutes for E, or may be a dopant doped material. For example, in the compound of Formula 2, for example, E is barium (Ba), E 'is strontium (Sr) or calcium (Ca), and T is cobalt (Co). In this case, strontium (Sr) or calcium (Ca) may function as a substance substituting for barium (Ba), or may function as a dopant to be additionally doped.

In addition, the compound of formula (2) may comprise, for example, RE _{1- x} E ' _x TO _{5 + δ} and may include compounds such as, for example, RBa _{1 - x} Sr _x Co ₂ O _{5 +} Where x is a number greater than zero and less than one. In addition, the compound of formula (2) may be, for example, RBa _{0 . 25} Sr _{0 . 75} Co ₂ O _{5 + delta} . In addition, the compound of formula (2) may contain various compounds according to the above R. For example, the compound represented by Formula 2 may be represented by NdBa _{1- x} Sr _x Co ₂ O _{5 +}隆, PrBa _{1 - x} Sr _x Co ₂ O _{5 +}隆, SmBa _{1 - x} Sr _x Co ₂ O _{5 +} GdBa _{1 - x} Sr _x Co may include a compound represented by the ₂ O _{5 + δ,} for example, NdBa _{0. 25} Sr _{0 . 75} Co ₂ O _{5 +}隆, PrBa _{0 . 25} Sr _{0 . 75} Co ₂ O _{5 +} ?, SmBa _0.25 Sr _0.75 Co ₂ O _{5 +} ?, Or GdBa _{0 . 25} Sr _{0 . 75} Co ₂ O _{5 + delta} . It is also included in the technical idea of the present invention that the above compound contains another alkaline earth metal instead of barium (Ba) or strontium (Sr), or contains other transition metal instead of cobalt (Co).

According to an embodiment of the present invention, the perovskite crystal structure material constituting the electrode may include a compound represented by the following formula (3).

(3)

RETT'O _{5 + δ}

In Formula 3, R may include one or more elements selected from the Lanthanon family, and E may include one or more elements selected from the group of the alkaline earth metals, and T and T ' And O may be oxygen, and the value of? Is a positive number of 0 or 1 or less, and the value of the compound of the above formula (3) is an electrical neutrality.

In the above formula (3), T and T 'may include one or more elements selected from transition metals, for example, manganese (Mn), cobalt (Co), iron (Fe), copper (Ni), or a mixture thereof. The T 'may be an element that substitutes the T to occupy the position of T in the compound of formula (3).

In addition, the compound of formula (3) may comprise, for example, RET _{2 - y} T ' _y O _{5 + δ} , wherein y is a number greater than 0 and less than 2. In addition, the compound of formula (3) may contain various compounds according to the above R. For example, the compound of Formula 3 may be represented by NdBaMn _{2 - y} Co _y O _{5 + δ} , PrBaMn _{2 - y} Co _y O _{5 + δ} , SmBaMn _{2 - y} Co _y O _{5 + δ} , or GdBaMn _{2 - y} Co It may include a compound represented by _y O _{5 + δ.} It is also included in the technical idea of the present invention that the above compound contains another alkaline earth metal instead of barium (Ba) or strontium (Sr), or contains other transition metal instead of cobalt (Co).

The perovskite crystal structure material constituting the electrode according to an embodiment of the present invention may include a compound represented by the following formula (4).

≪ Formula 4 >

REE'TT'O _{5 + δ}

In Formula 4, R may include one or more elements selected from lanthanides, E and E 'are different elements selected from an alkaline earth metal group, and T and T' are selected from transition metals May contain different elements, O is oxygen, and? Is a positive number of 0 or 1 or less, which is a value that makes the compound of Formula 4 electrically neutral.

In Formula 4, E 'may be a substance to replace E, or may be doped dopant material. For example, in the compound of Formula 4, for example, E is barium (Ba), E 'is strontium (Sr) or calcium (Ca), and T is cobalt (Co). In this case, strontium (Sr) or calcium (Ca) may function as a substance substituting for barium (Ba), or may function as a dopant to be additionally doped.

In Formula 4, T and T 'may include one or more elements selected from transition metals, and examples thereof include Mn, Co, Fe, Cu, (Ni), or a mixture thereof. The T 'may be an element that substitutes the T to occupy the position of T in the compound of formula (4).

In addition, the, for example, RE _{1- x} E a compound of formula 4 _'x T _{2 -} T _{y' y} O may include a _{5 + δ,} wherein x here is a number from more than 0 to less than 1, and the y Is a number greater than 0 and less than 2. In addition, the compound of formula (4) may contain various compounds according to the above-mentioned R. For example, the compound of Formula 4 may be represented by NdBa _{1 - x} Sr _x Mn _{2 - y} Co _y O _{5 + δ} , PrBa _{1 - x} Sr _x Mn _{2 - y} Co _y O _{5 + δ} , SmBa _{1 - x} Sr _x Mn _2-y Co _y O _{5 + delta} , or GdBa _{1 - x} Sr _x Mn _{2 - y} Co _y O _{5 + delta} . It is also included in the technical idea of the present invention that the above compound contains another alkaline earth metal instead of barium (Ba) or strontium (Sr), or contains other transition metal instead of cobalt (Co).

Hereinafter, a method of manufacturing an electrode using an electrode material according to the technical idea of the present invention will be described. Illustratively, a perovskite crystal structure was used as the powdery structure.

The electrode manufacturing method first forms the perovskite crystal structure described above. The perovskite crystal structure may be formed by mixing each of the metal precursors metered in accordance with the composition of any one of Chemical Formulas 1 to 4 (for example, wet using a solvent) Obtaining a solid from the mixture, firing the solid in air to obtain a fired product, and polishing the fired product.

The metal precursor is mixed in a stoichiometric ratio to obtain the compound of the above formula. Examples of the metal precursor include, but are not limited to, nitrides, oxides, halides, and the like of each component constituting the electrode of the above formula. For example, the metal precursor may be a nitride, an oxide, a halide, or the like including at least one of Pr, Ba, Mn, Co, and Ni.

In the step of mixing the metal precursor with the solvent, water may be used as a solvent, but the present invention is not limited thereto. The metal precursor can be used without limitation as long as it can dissolve the metal precursor. For example, a lower alcohol having 5 or less carbon atoms, such as methanol, ethanol, 1-propanol, 2-propanol and butanol; Acidic solutions such as nitric acid, hydrochloric acid, sulfuric acid, and citric acid; water; Organic solvents such as toluene, benzene, acetone, diethyl ether and ethylene glycol; May be used alone or in combination.

The step of mixing the metal precursor with the solvent may be performed at a temperature in the range of about 100 ° C to about 200 ° C and may be carried out for a predetermined time under agitation so that each component can be thoroughly mixed. The mixing process, removing the solvent, and addition of additives required for this purpose are well known, for example, by the pechini method, and therefore are not described here.

After the mixing process, ultrafine solid material can be obtained by spontaneous combustion. The ultrafine solid can then be heat treated (calcined, sintered) for a time period ranging from about 400 ° C. to about 950 ° C. for a time period ranging from about 1 hour to about 5 hours, for example, at about 600 ° C. for about 4 hours. Whereby a perovskite crystal structure is formed.

Next, an electrode material having metal oxide nanoparticles formed on the surface of the perovskite crystal structure is formed through an impregnation method and a sintering process as described above with reference to FIG.

If necessary, the electrode material may be subjected to a second heat treatment (calcination, sintering). This second heat treatment step is a step of calcining in air for about 12 hours at a temperature in the range of about 950 ° C to about 1500 ° C, for a period of about 1 hour to about 24 hours, for example, at a temperature in the range of about 950 to about 1500 ° C To obtain a powdery product.

Then, the fired product may be ground or pulverized to obtain a fine powder having a predetermined size. For example, milling and mixing by ball milling in acetone for about 24 hours. Next, the mixed powder is put in a metal mold and pressed, and then pressed pellets are sintered in the atmosphere to prepare an electrode material. Sintering may be performed at a temperature in the range of about 950 ° C to about 1500 ° C for a period ranging from about 12 hours to about 24 hours, for example, at a temperature in the range of from about 950 to about 1500 ° C for a period of about 24 hours, . The fired resultant may be ground or pulverized to obtain a fine powdery electrode material of a predetermined size.

From the electrode material, an anode or a cathode electrode can be manufactured. For example, the anode may be formed by coating the electrode material on a substrate, followed by heat treatment. The heat treatment may be performed in a reducing atmosphere such as a hydrogen atmosphere. The heat treatment may be performed at a temperature in the range of, for example, about 700 ° C to about 800 ° C. The heat treatment may be performed under a hydrogen pressure of, for example, about 3 atm. The thickness of the electrode may range from about 1 [mu] m to about 100 [mu] m. For example, the thickness of the electrode may range from about 5 [mu] m to about 50 [mu] m.

FIGS. 4 and 5 are SEM micrographs of an electrode material manufactured according to an embodiment of the present invention. FIG. 4 is a photograph before the impregnation method is performed, and FIG. 5 is a photograph after the impregnation method is performed.

4 and 5, before the impregnation method was performed, the powdery structure composed of the perovskite crystal structure showed a smooth surface. However, after the impregnation method was performed, the surface of the powdery structure was coated with the cobalt oxide nanocomposite Particles are formed.

6 is a graph showing an oxygen reduction reaction of an electrode material manufactured according to an embodiment of the present invention.

The graph of FIG. 6 was measured by a Rotating Ring Disk Electrode (RRDE) measurement method in a 0.1 M KOH electrolyte. In Fig. 6, " Pt / C " represents a case where a carbon electrode and a platinum catalyst are used, " A (pechini) " corresponds to a case of a perovskite crystal structure formed by the Pecini method, quot; commercial " corresponds to a commercially available cobalt oxide nanomaterial, and " A + B " corresponds to a case where the above materials are simply mixed.

For example, in the development of zinc metal air cells, a slow oxygen reduction reaction is becoming the biggest problem. That is, in the battery discharge reaction, the OH ^- ion consumption rate at the zinc cathode is much larger than the OH ^- ion production rate at the cathode, so that the OH ^- ion concentration in the electrolyte is rapidly lowered, have. Therefore, it is required to develop a material having a rapid oxygen reduction reaction.

Referring to FIG. 6, after the impregnation and sintering, the electrode material exhibits similar behavior to that of the Pt / C electrode, which is a noble metal catalyst, and the tendency of the oxygen reduction reaction current (i _ORR ) Which is the closest value. That is, the electrode material has a greatly increased oxygen reduction activity, which means that a rapid oxygen reduction reaction can be provided. In addition, the electrode material of the present invention exhibits excellent oxygen reduction performance as compared with any of the perovskite structure materials reported previously, and exhibits superior performance to carbon. An excellent electrode material for an oxygen reduction reaction must have a condition where the oxygen reduction reaction starts at a higher voltage and generates a large current under the same voltage. Therefore, the electrode material manufactured according to one embodiment of the present invention can provide excellent performance for the oxygen reduction reaction.

7 is a graph showing an oxygen generating reaction of an electrode material manufactured according to an embodiment of the present invention. The graph of FIG. 7 was measured by a rotating ring disc electrode measurement method in a 0.1 M KOH electrolyte.

Referring to FIG. 7, after the impregnation and sintering processes are performed on the electrode material, the amount of current generated under the same voltage is greatly increased. Since the electrode material exhibits a large increase in the amount of current as compared with other materials including Pt / C, it can provide excellent performance for the oxygen generating reaction.

Since the air electrode of the commercialized metal air cell is required to have a noble metal catalyst such as platinum due to the slow oxygen reduction reaction, there is a limit in manufacturing cost. Therefore, the electrode material according to the present invention has sufficient electric characteristics at room temperature, has a high oxygen reduction activity, and can be used as a cathode capable of reducing the price of precious metals.

The case where the electrode material is applied to the cathode of the metal air battery is also included in the technical idea of the present invention.

FIG. 8 is a schematic view illustrating a metal air cell 100 including an electrode formed of an electrode material according to an embodiment of the present invention.

Referring to FIG. 8, the metal air cell 100 includes an anode 110 as a cathode, a cathode 120 as an anode, and an electrolyte 130 positioned between the anode 110 and the cathode 120. The cathode 120 may further include a current collector 140 and a catalyst body 150.

The metal air cell 100 generates electric power by using a reaction between metal and oxygen. The greatest advantage of the metal air cell 100 is that it uses oxygen existing in the natural world as an active material and possesses a very high theoretical energy density as compared with other secondary batteries and also possesses an affinity characteristic. In addition, since the metal air cell 100 does not contain a chemical oxidizer therein, there is no risk of explosion or fire, and the weight can be greatly reduced. In addition, it is very economical, superior in stability, and operates at low temperatures as compared with a fuel cell using hydrogen or alcohol.

The anode 110 may include a material that becomes a cation when it loses electrons at the time of discharging, and may include, for example, a metal and may include, for example, lithium, zinc, magnesium, aluminum, and calcium. In particular, lithium has a theoretical energy density of 11,140 Wh / kg, which is almost similar to that of gasoline at 13,000 Wh / kg. For reference, aluminum has a theoretical energy density of 8130 Wh / kg, calcium 4180 Wh / kg and zinc 1350 Wh / kg. In addition, the anode 110 may be formed using an electrode material according to the technical idea of the present invention.

The cathode 120 is configured to use oxygen in the air, and can collect the oxygen. The cathode 120 may further include a collector 140 of a porous material for collecting oxygen and a catalyst body 150 for activating a reduction reaction of oxygen. The cathode 120 may be formed using an electrode material according to the technical idea of the present invention. The metal air cell 100 can use the oxygen in the air as the cathode 120, and theoretically, the weight of the cathode 120 can be reduced to zero or significantly. Therefore, since the weight of the anode 110 can be increased by reducing the weight of the cathode 120, the weight ratio of the anode 110 to the total weight of the metal air cell 100 is increased, It can provide a high energy density per unit weight.

The electrolyte 130 is disposed between the anode 110 and the cathode 120 and may include an electrolytic material. The electrolyte 130 may include, for example, a sodium hydroxide (NaOH) solution or a calcium hydroxide (KOH) solution. Also, the electrolyte 130 may be composed of a solid-phase medium.

Hereinafter, power generation in the metal air battery 100 will be described. The anode 110 and the cathode 120 may be subjected to a discharge reaction and a charging reaction. The discharge reaction in the anode 110 and the cathode 120 is as follows. The charging reaction is such that the following reactions are directed to the opposite echo. In the following reaction formula, " M " may be a metal as a material constituting the anode 110.

<Anode Reaction>

M -> M ⁺ + e ^-

<Cathode reaction>

2 (M ⁺ + e ^- ) + O ₂ - > M ₂ O ₂

The positive ions 170 formed on the anode 110 through the discharge reaction are directed to the cathode 120 through the electrolyte 130. At this time, the electrons whose positive and negative ions are lost pass through the load 190 through separate conductors, thereby supplying power to the load 190 as a result.

Oxygen 180 from the outside is supplied to the cathode 120 and the cation 170 reacts with the oxygen 180 and the cathode 120 to form an oxide. At this time, electrons passing through the load 190 are supplied to the cathode 120 to form the oxide together.

On the other hand, at the time of charging, the oxide is decomposed, and the cation acquires electrons and returns from the cathode 120 to the anode 110 through the electrolyte 130.

The electrode material according to the technical idea of the present invention can constitute the electrode substrate of the cathode and the anode or constitute a catalyst body attached to the electrode substrate.

Also, the case where the electrode material is applied to the anode and the cathode of the solid oxide fuel cell is included in the technical idea of the present invention.

9 is a schematic diagram of a solid oxide fuel cell 200 including an electrode formed of an electrode material, in accordance with an embodiment of the present invention.

9, the solid oxide fuel cell 200 includes an anode 210, a cathode 220 disposed opposite the anode 210, and an anode 210 disposed between the anode 210 and the cathode 220, And an electrolyte 230 which is a solid oxide. And optionally a buffer layer 240 disposed between the anode 210 and the electrolyte 230.

Solid oxide fuel cells of the fuel 200, as shown in electrochemical reaction is the following reaction scheme, a cathode 220, oxygen gas O ₂ has an anode reaction and the anode 210, changing the oxygen ions O ^2- of the (H ₂ or hydrocarbon ) And oxygen ions that have moved through the electrolyte.

<Reaction Scheme>

Anode reaction: 1/2 O ₂ + 2e ^- -> O ^2-

Cathode reaction: H ₂ + O ^2- -> H ₂ O + 2e ^-

In the cathode 220 of the solid oxide fuel cell 200, oxygen adsorbed on the surface of the electrode is dissociated and diffused to form a triple phase boundary where the electrolyte 230, the cathode 220 and the pores (not shown) The oxygen ions are converted into oxygen ions, and the generated oxygen ions are transferred to the anode 210, which is a fuel electrode, through the electrolyte 230.

In the anode 210 of the solid oxide fuel cell 200, the moved oxygen ions combine with the hydrogen contained in the fuel to generate water. At this time, hydrogen evolves electrons to hydrogen ions (H ⁺ ) and binds to the oxygen ions. The discharged electrons move to the cathode 220 through wiring (not shown) to change oxygen to oxygen ions. Through this electron transfer, the solid oxide fuel cell 200 can perform the battery function.

The solid oxide fuel cell 200 can be manufactured by using a conventional method known in the art, so a detailed description thereof will be omitted here. In addition, the solid oxide fuel cell 200 can be applied to various structures such as a tubular stack, a flat tubular stack, a planar type stack, and the like.

The solid oxide fuel cell 200 may be in the form of a stack of unit cells. For example, a unit cell (MEA) composed of an anode 210, a cathode 220, and an electrolyte 230 is stacked in series, and a separator plate (not shown) a stack of unit cells can be obtained with a separator interposed therebetween.

At least one of the anode 210 and the cathode 220 may be formed using the electrode material according to the technical idea of the present invention.

The electrolyte 230 is not particularly limited as long as it can be generally used in the art. For example, the electrolyte 230 may be a stabilized zirconia based system such as yttria stabilized zirconia (YSZ) and scandia stabilized zirconia (ScSZ); Ceria systems doped with rare earth elements such as samaria-doped ceria (SDC), gadolinia-doped ceria (GDC) and the like; Other LSGM ((La, Sr) (Ga, Mg) O ₃ ) system; And the like. In addition, the electrolyte 230 may include strontium or magnesium-doped lanthanum gallate.

The buffer layer 240 may be positioned between the anode 210 and the electrolyte 230 to provide a smooth contact. The buffer layer 240 may function to mitigate, for example, crystal lattice distortion between the anode 210 and the electrolyte 230. Buffer layer 240 may include, for example, the _{LDC (La 0. 4 Ce 0} . 6 O 2 -δ). The buffer layer 240 may be omitted as an optional component.

The electrode material according to the technical idea of the present invention can constitute the electrode substrate of the cathode and the anode or constitute a catalyst body attached to the electrode substrate.

Also, the case where the electrode material is applied to the anode and the cathode of the solid oxide electrolytic cell is also included in the technical idea of the present invention.

FIG. 10 is a view schematically showing a solid oxide electrolytic cell 300 including an electrode formed of an electrode material, according to an embodiment of the present invention.

10, the solid oxide acceptance cell 300 includes an anode 310, a cathode 320 disposed opposite the anode 310, and an anode 310 disposed between the anode 310 and the cathode 320, And an electrolyte 330 which is a conductive solid oxide. The cathode 320 may be referred to as a hydrogen electrode because it is in contact with hydrogen gas, and the anode 310 may be referred to as an oxygen electrode in contact with oxygen gas.

The electrochemical reaction of the solid oxide water electrolytic cell 300 is performed by an anode reaction in which water (H ₂ O) in the cathode 320 is converted into hydrogen gas (H ₂ ) and oxygen ions (O ^2- ) And an anode reaction in which the oxygen ions that have been moved through the electrolyte 330 are converted into oxygen gas (O ₂ ). This reaction is opposite to the reaction principle of a typical fuel cell.

<Reaction Scheme>

Cathode reaction: H ₂ O + 2e ^- -> O ^2- + H ₂

Anode reaction: O ^2- -> 1/2 O ₂ + 2e ^-

When power is applied to the solid oxide electrolytic cell 300 from the external power supply 340, electrons are supplied from the external power supply 340 to the solid oxide electrolytic cell 300. The electrons react with water supplied to the cathode 320 to generate hydrogen gas and oxygen ions. The hydrogen gas is discharged to the outside, and the oxygen ions are transferred to the anode 310 through the electrolyte 330. The oxygen ions transferred to the anode 310 lose electrons and are converted into oxygen gas and discharged to the outside. The electrons flow to the external power source 340. Through this electron transfer, the solid oxide electrolytic cell 300 can electrolyze water to form hydrogen gas at the cathode 320 and oxygen gas at the anode 310.

At least one of the anode 310 and the cathode 320 may be formed using the electrode material according to the technical idea of the present invention.

The electrolyte 330 is not particularly limited as long as it can be generally used in the art. The electrolyte 330 may include the same material as the electrolyte 230 of the solid oxide fuel cell 200 described above, or may have the same structure.

The electrode material according to the technical idea of the present invention can constitute the electrode substrate of the cathode and the anode or constitute a catalyst body attached to the electrode substrate.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. Will be apparent to those of ordinary skill in the art.

100: metal air cell, 110: anode, 120: cathode, 130: electrolyte,
140: current collector, 142: carbon body, 144: conductive polymer material,
150: catalyst, 170: cation, 180: oxygen, 190: load,
200: solid oxide fuel cell, 210: anode,
220: cathode, 230: electrolyte, 240: buffer layer,
300: solid oxide electrolytic cell, 310: anode, 320: cathode,
330: electrolyte, 340: external power supply,

Claims (20)

Providing powder shaped structures;
Impregnating the powdery structures with a metal precursor solution containing a metal nitride; And
Treating the impregnated powdery structures at a temperature ranging from 400 ° C to 500 ° C and sintering the metal precursor to form metal oxide nanoparticles on the surfaces of the powdery structures,
Wherein the metal nitride comprises at least one of Co (NO ₃ ) ₂ .6H ₂ O, Nd (NO ₃ ) ₃ .6H ₂ O, Ba (NO ₃ ) ₂ , and Sr (NO ₃ ) ₂ ,
Wherein the metal precursor solution uses an alcohol-based solution as a solvent. delete delete delete delete The method according to claim 1,
Wherein the metal oxide nanoparticles are in a range of 10 wt% to 20 wt% with respect to the total weight of the electrode material. The method according to claim 1,
Wherein the powdery structures include a perovskite crystal structure. The method of claim 7,
Wherein the perovskite crystal structure comprises a compound of the following formula (1).
&Lt; Formula 1 >
RETO _{5 + δ}
Wherein R comprises one or more elements selected from rare earth elements or lanthanides, E comprises one or more elements selected from the group of the alkaline earth metals, and T is selected from the group consisting of one selected from transition metals Or more, O is oxygen, and? Is a positive number of 0 or 1 or less, and is a value that makes the compound of formula (1) electrically neutral. The method of claim 8,
In the above formula (1), R is at least one selected from the group consisting of Y, neodymium, praseodymium, scandium, samarium, gadolinium, Er), or a mixture thereof. The method of claim 8,
Wherein E is at least one selected from the group consisting of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), radium (Ra) Way. The method of claim 8,
In Formula 1, T is at least one element selected from the group consisting of Mn, Co, Fe, Cu, Cr, Ni, Ti, &Lt; / RTI &gt; The method of claim 7,
Wherein the perovskite crystal structure comprises a compound represented by the following formula (2).
(2)
REE'TO _{5 + δ}
Wherein R is one or more elements selected from a rare earth group or a lanthanide group, E and E 'are different elements selected from an alkaline earth metal group, and T is one or more selected from transition metals And O is oxygen, and the delta is a positive number of 0 or 1 or less, and the compound of Formula 2 is a value that is electrically neutral. The method of claim 7,
Wherein the perovskite crystal structure comprises a compound represented by the following formula (3).
(3)
RETT'O _{5 + δ}
In Formula 3, R may include one or more elements selected from the Lanthanon family, and E may include one or more elements selected from the group of the alkaline earth metals, and T and T ' And O may be oxygen, and the value of? Is a positive number of 0 or 1 or less, and the value of the compound of the above formula (3) is an electrical neutrality. The method of claim 7,
Wherein the perovskite crystal structure comprises a compound represented by the following formula (4).
&Lt; Formula 4 >
REE'TT'O _{5 + δ}
In Formula 4, R may include one or more elements selected from lanthanides, E and E 'are different elements selected from an alkaline earth metal group, and T and T' are selected from transition metals May contain different elements, O is oxygen, and? Is a positive number of 0 or 1 or less, which is a value that makes the compound of Formula 4 electrically neutral. The method of claim 7,
Wherein the perovskite crystal structure comprises at least one of NdBaCo ₂ O _{5 + δ} , PrBaCo ₂ O _{5 + δ} , SmBaCo ₂ O _{5 + δ} , GdBaCo ₂ O _{5 + δ} , NdSrCo ₂ O _{5 + δ} , PrSrCo ₂ O _{5 + , SmSrCo 2 O 5 + δ,} GdSrCo 2 O 5 + δ, NdBa 1 - x Sr x Co 2 O 5 + δ, PrBa 1-x Sr x Co 2 O 5 + δ, SmBa 1 - x Sr x Co 2 O _{5 + δ, GdBa 1 - x} Sr x Co 2 O 5 + δ, NdBaMn 2 - y Co y O 5 + δ, PrBaMn 2 -y Co y O 5 + δ, SmBaMn 2 - y Co y O 5 + δ, _{GdBaMn 2 - y Co y O 5} + δ, NdBa 1 - x Sr x Mn 2 - y Co y O 5 + δ, PrBa 1 - x Sr x Mn 2 -y Co y O 5 + δ, SmBa 1 - x Sr _x Mn _{2 - y} Co _y O _{5 +} ?, and GdBa _{1 - x} Sr _x Mn _{2 - y} Co _y O _{5 +?} where x is a number greater than 0 but less than 1 and y is a number greater than 0 and less than 2 ). &Lt; / RTI &gt; The method of claim 7,
Wherein the perovskite crystal structure comprises a single-layered perovskite crystal structure material or a double-layered perovskite crystal structure material. delete delete delete delete

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