KR20200076615A - Catalyst particle, Li-air battery having the same and method of manufacturing air electrode catalyst for Li-air battery - Google Patents

Abstract

The present invention relates to a catalyst particle, a lithium-air battery including the same, and a method for preparing a cathode catalyst for a lithium-air battery. More particularly, the present invention relates to a catalyst particle capable of increasing battery capacity, a lithium-air battery including the same, and a method for preparing a cathode catalyst for a lithium-air battery. The catalyst particle according to an embodiment of the present invention comprises: a shell unit surrounding an inner receiving space and having pores forming a flow path; and a yoke unit provided to be at least partially spaced apart from an inner surface of the receiving space of the shell unit.

Description

Catalyst particle, Li-air battery having the same and method of manufacturing air electrode catalyst for Li-air battery}

The present invention relates to a catalyst particle, a lithium-air battery comprising the same, and a method for preparing an anode catalyst for a lithium-air battery, more specifically, a catalyst particle capable of increasing the battery capacity, a lithium-air battery comprising the same, and lithium- The present invention relates to a method for manufacturing an anode catalyst for an air battery.

Recently, as the demand for electric vehicles and energy storage devices (ESSs) increases, the importance of next-generation secondary batteries capable of storing large amounts of energy has been emphasized. The lithium-air battery has a theoretical energy density of about 3,500 Wh/kg, which is about 10 times higher than that of a conventional lithium ion battery.

Lithium-air batteries, unlike lithium-ion batteries that contain a positive electrode material inside the battery, use oxygen in the air, so the weight of the battery is light and the energy density is very excellent because oxygen can be supplied indefinitely.

In addition, the lithium-air battery is driven through the principle that lithium and oxygen meet at the air electrode during discharge to generate lithium oxide, and lithium oxide decomposes back to lithium and oxygen at the air electrode during charging.

Therefore, the cathode of the lithium-air battery should be a structure having sufficient space for lithium oxide to be smoothly generated and decomposed, and a catalyst capable of lowering the overvoltage during charging and discharging.

Korean Patent Publication No. 10-2012-0100939

The present invention provides a catalyst particle capable of increasing battery capacity when applied to an anode catalyst through a yoke-shell structure, a lithium-air battery comprising the same, and a method for preparing an anode catalyst for a lithium-air battery.

Catalytic particles according to an embodiment of the present invention surrounds the receiving space therein, the shell having pores to form a flow path; And a yoke portion provided to be spaced at least partially from the inner surface of the accommodation space of the shell portion.

The shell portion and the yoke portion may be made of the same material.

The volume of the yoke portion may be smaller than the volume of the accommodation space.

The shell portion and the yoke portion may be made of an oxide containing at least one of Fe, Co, Mn, and Ni.

A lithium-air battery according to another embodiment of the present invention includes an air cathode including an anode catalyst made of catalyst particles according to an embodiment of the present invention; A lithium electrode disposed in correspondence with the air electrode and including lithium metal; A separator provided between the air electrode and the lithium electrode; And an electrolyte electrically connecting the air electrode and the lithium electrode.

A method for preparing an anode catalyst for a lithium-air battery according to another embodiment of the present invention includes a process of preparing a precursor solution in which a precursor is dissolved in a solvent; Preparing a spray solution by adding a carbon compound to the precursor solution; Spraying the spray solution with droplets; And applying heat to the droplets to generate catalyst particles of a yoke-shell structure composed of a shell portion having pores and a yoke portion provided in the receiving space of the shell portion.

The process of generating the catalyst particles includes: providing heat to the droplets in an oxidizing atmosphere; A process in which carbon contained in the surface of the droplet burns; A process of solidifying the surface of the droplet by at least the combustion energy of carbon to form the shell portion; And shrinking the remaining droplets inside the shell portion to form the yoke portion separated from the shell portion.

The precursor may include at least one salt selected from the group consisting of acetate, nitrate, carbonate, chloride, hydroxide and oxide. .

The molar concentration of the precursor solution in the spray solution may be 0.02 to 1 M.

The molar concentration of the carbon compound in the spray solution may be 0.02 to 1 M.

The process of generating the catalyst particles may be performed by adding heat of 600 to 1,000°C to the droplets.

The catalyst particles may be made of an oxide containing at least one of Fe, Co, Mn and Ni.

The catalyst particles according to the embodiment of the present invention are composed of a shell portion having pores and a yoke portion provided in the receiving space of the shell portion, and thus have a yoke-shell structure that forms an empty space between the shell portion and the yoke portion. The specific surface area may be increased, and when used in a cathode for a lithium-air battery, a large amount of lithium oxide (for example, Li ₂ O ₂ ), which is a reaction product of the lithium-air battery due to an empty space between the shell portion and the yoke portion, It can also provide space that can be created.

The lithium-air battery including the cathode catalyst made of the catalyst particles can increase the catalytically active area of the catalyst particles, thereby improving the reactivity of the cathode catalyst, thereby increasing the battery capacity.

In addition, the method for manufacturing an anode catalyst for a lithium-air battery can produce a catalyst having a yoke-shell structure by generating catalyst particles through a spray pyrolysis process using droplets of a spray solution containing a precursor and a carbon compound. Lithium-air battery comprising an air cathode made of a catalyst can exhibit a high capacity, and can realize a lithium-air battery having excellent cycle characteristics.

1 is a schematic diagram showing catalyst particles according to an embodiment of the present invention.
Figure 2 is an image for explaining the catalyst particles according to an embodiment of the present invention.
3 is a graph showing the result of X-ray diffraction (XRD) analysis of catalyst particles according to an embodiment of the present invention.
4 is a graph showing the initial discharge capacity of a lithium-air battery according to another embodiment of the present invention.
5 is a graph showing the cycle characteristics of a lithium-air battery according to another embodiment of the present invention.
Figure 6 is a flow chart showing a method of manufacturing a cathode catalyst for a lithium-air battery according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and the scope of the invention to those skilled in the art is completely It is provided to inform you. In the description, the same reference numerals are assigned to the same components, and the drawings may be exaggerated in size in order to accurately describe embodiments of the present invention, and the same reference numerals in the drawings refer to the same elements.

1 is a schematic view showing a catalyst particle according to an embodiment of the present invention, Figure 1 (a) is a plan view of the catalyst particles, Figure 1 (b) is a cross-sectional view of the catalyst particles.

Referring to Figure 1, the catalyst particle 100 according to an embodiment of the present invention surrounds the receiving space 111, the shell portion 110 having pores 112 forming a flow path; And a yoke portion 120 provided to be spaced at least partially from the inner surface of the accommodation space 111 of the shell portion 110.

The shell portion 110 may be an epidermal layer (or shell) surrounding the inner portion to form a receiving space 111, and forms a flow path communicating the inside (ie, the receiving space) of the shell portion 110 with the outside. It may be porous (porous) having a pore (pore, 112). When the catalyst particles 100 are used for the cathode catalyst of the lithium-air battery, lithium ions and/or air (or oxygen) may be moved to the accommodation space 111 through the pores 112, and thus the pores 112 ), as well as the inner surface of the shell portion 110 and the yoke portion 120 may be catalyzed.

The yoke part 120 may be provided to be spaced at least partially from the inner surface of the accommodation space 111 of the shell part 110, and an empty space may be formed between the shell part 110 and flowable. It may be provided. The yoke portion 120 may provide a catalytically active area by exposing at least a portion of the surface away from the inner surface of the receiving space 111.

When the yoke portion 120 is provided to be flowable, the yoke portion 120 may receive space according to the direction of an acting force (that is, an acting force) and/or a material supply between the shell portion 110 and the yoke portion 120 The location can be determined within (111). For example, the electrolyte or the like is filled between the shell portion 110 and the yoke portion 120 so that the yoke portion 120 is spaced apart from the shell portion 110, so that the entire surface of the yoke portion 120 may participate in the catalytic reaction. On the other hand, the yoke portion 120 may flow in the receiving space 111, the surface of the yoke portion 120, the surface where the catalytic reaction occurs may change according to the flow of the yoke portion 120, the yoke in the catalytic reaction The entire surface of the portion 120 can be used.

The catalyst particles 100 may have a larger specific surface area than the general spherical catalyst particles, and when used in an air electrode for a lithium-air battery, lithium-air due to an empty space between the shell portion 110 and the yoke portion 120 Lithium oxide (for example, Li ₂ O ₂ ), which is a reaction product of the battery, may provide a space for mass production.

And the shell portion 110 and the yoke portion 120 may be made of the same material. Since the shell part 110 and the yoke part 120 are made of the same material, both the shell part 110 and the yoke part 120 can be used as catalysts. Accordingly, since the catalytic reaction occurs on both the surface of the shell portion 110 and the surface of the yoke portion 120, the catalytically active area can be increased.

The volume of the yoke portion 120 may be smaller than the volume of the receiving space 111 (or the inner volume of the shell portion). Accordingly, the yoke portion 120 may flow in the accommodation space 111, and at least a portion of the surface of the yoke portion 120 may be spaced apart from the inner surface of the shell portion 110. Through this, the catalytically active area of the surface of the yoke portion 120 can be secured.

At this time, the volume of the yoke portion 120 may be 50 to 80% of the volume of the receiving space 111. When the volume of the yoke portion 120 is greater than 80%, the space between the shell portion 110 and the yoke portion 120 may not be sufficiently secured, so that a space in which lithium oxide, a reaction product of a lithium-air battery, can be generated Not sufficiently provided, or the yoke portion 120 may interfere with the flow of lithium ions and/or air in the accommodation space 111. On the other hand, when the volume of the yoke portion 120 is less than 50%, the surface area of the yoke portion 120 is too small, so that an increase in the catalytically active area may be negligible, and the yoke portion 120 may be smaller than the width of the pores 112. In a small case, the yoke portion 120 may escape from the accommodation space 111.

Here, the width of the yoke portion 120 may be 100 to 500 nm. When the width of the yoke portion 120 is greater than 500 nm, an empty space between the shell portion 110 and the yoke portion 120 may not be sufficiently secured. On the other hand, when the width of the yoke portion 120 is less than 100 nm, the surface area of the yoke portion 120 is too small, so that an increase in the catalytically active area may be negligible. In addition, the width (or inner width) of the accommodation space 111 of the shell portion 110 may be 100 to 500 nm. When the width of the accommodation space 111 is larger than 500 nm, the empty space between the shell portion 110 and the yoke portion 120 may be large, but the specific surface area is low and thus the catalytically active area may be insignificant. On the other hand, when the width of the accommodation space 111 is smaller than 100 nm, the empty space between the shell portion 110 and the yoke portion 120 may not be sufficiently secured.

In addition, the shell part 110 and the yoke part 120 may be made of an oxide containing at least one of Fe, Co, Mn, and Ni. When the catalyst particles 100 made of these oxides are used in a cathode for a lithium-air battery, lithium oxide can be smoothly generated and decomposed by promoting the reaction between lithium ions and air.

Figure 2 is an image for explaining the catalyst particles according to an embodiment of the present invention, Figure 2 (a) is a scanning electron microscope (Scanning Electron Microscope; SEM) analysis results of the catalyst particles, Figure 2 (b) is The results of the transmission electron microscope (TEM) analysis of the catalyst particles are shown, and FIG. 2(c) shows the results of dot-mapping analysis of the catalyst particles.

2(a) and 2(b), it can be seen that the catalyst particles 100 are manufactured in a spherical shape having a size of about 1 μm, and the catalyst particles 100 in FIG. 2(b) have a yoke portion. It can be seen that there was a space between the 120 and the shell part 110, and a yoke-shell structured particle was formed. In particular, referring to FIG. 2(c), it can be confirmed that Mn and Co are uniformly distributed inside the catalyst particle 100.

3 is a graph showing the results of X-ray diffraction (XRD) analysis of catalyst particles according to an embodiment of the present invention.

Referring to Figure 3, it can be seen that the catalyst particles 100 having a yoke-shell structure have high crystallinity and a pure phase.

Hereinafter, a lithium-air battery according to another embodiment of the present invention will be described in more detail, and details overlapping with the above-described parts of the catalyst particle according to an embodiment of the present invention will be omitted.

A lithium-air battery according to another embodiment of the present invention includes an air cathode including an anode catalyst made of catalyst particles according to an embodiment of the present invention; A lithium electrode disposed in correspondence with the air electrode and including lithium metal; A separator provided between the air electrode and the lithium electrode; And an electrolyte electrically connecting the air electrode and the lithium electrode.

The cathode may include an anode catalyst composed of catalyst particles according to an embodiment of the present invention, and the catalyst particles have a yoke-shell structure composed of a yoke (or core) portion and a shell portion, and the catalyst particles The catalytic activity area of can be increased, and the reactivity of the cathode catalyst can be improved. Accordingly, the battery capacity of the lithium-air battery can be increased.

The lithium electrode (or negative electrode) may be disposed corresponding to the air electrode, and may be made of lithium metal.

A separator may be provided between the air electrode and the lithium electrode. Here, the separator may be a glass filter.

The electrolyte may electrically connect the air electrode and the lithium electrode. Here, the electrolyte may be prepared by dissolving 0.5 M of lithium bisamide (LiTFSI) and 0.5 M of LiNO ₃ in Triethylene Glycol Dimethyl Ether (TEGDME).

The lithium-air battery of the present invention may use an aqueous electrolyte and a non-aqueous electrolyte as the electrolyte, and when using a non-aqueous electrolyte, may exhibit a reaction mechanism as shown in Reaction Scheme 1.

<Scheme 1>

4Li + O ₂ ↔ 2Li ₂ OE _o = 2.91 V

2Li + O ₂ ↔ Li ₂ O ₂ E _o = 3.1 V

During discharge, lithium ions derived (or moved) from the lithium electrode meet oxygen introduced into the air electrode to generate lithium oxide, and oxygen is reduced (Oxygen Reduction Reaction; ORR).

<Reaction Scheme 2>

O ₂ + e → O ₂ ^-

_{^{O 2 - + Li + → LiO}} 2

LiO ₂ + Li ⁺ + e → Li ₂ O ₂

Conversely, lithium oxide is reduced and oxygen is oxidized during charging (Oxygen Evolution Reaction; OER). On the other hand, during discharge, lithium oxide (eg, Li ₂ O ₂ ) may precipitate in the pores of the air electrode, and the capacity of the lithium-air battery may increase as the area of the electrolyte contacting the air electrode increases. have.

<Scheme 3>

Li ₂ O ₂ → LiO ₂ + Li ⁺ + e

^{_{LiO 2 → O 2 - + Li}} +

O ₂ ^- → O ₂ + e

The lithium-air battery according to the present invention can provide a sufficient space for lithium oxide to be smoothly generated and decomposed, including an air electrode comprising an air cathode catalyst composed of catalyst particles having a yoke-shell structure, and charging and discharging It can act as a catalyst that can lower the overvoltage. Accordingly, a high capacity can be exhibited, and excellent cycle characteristics can be obtained.

4 is a graph showing the initial discharge capacity of a lithium-air battery according to another embodiment of the present invention, and FIG. 5 is a graph showing the cycle characteristics of a lithium-air battery according to another embodiment of the present invention.

Referring to Figure 4, it can be seen that the embodiment of the yoke-shell structure exhibits a capacity that is more than three times that of the comparative example of the hollow structure. Referring to Figure 5, it can be seen that the yoke-shell structure of the embodiment has better cycle characteristics (or longer life characteristics) than the comparative example of the hollow structure.

6 is a flowchart illustrating a method of manufacturing an anode catalyst for a lithium-air battery according to another embodiment of the present invention.

Referring to Figure 6 to look at in more detail the manufacturing method of the cathode catalyst for a lithium-air battery according to another embodiment of the present invention, the catalyst particles according to an embodiment of the present invention and lithium-air according to another embodiment of the present invention Regarding the battery, overlapping with the above-described parts will be omitted.

A method for preparing a cathode catalyst for a lithium-air battery according to an embodiment of the present invention includes a process of preparing a precursor solution in which a precursor is dissolved in a solvent (S100); Preparing a spray solution by adding a carbon compound to the precursor solution (S200); A process of spraying the spray solution as a droplet (S300); And heating the droplets to generate catalyst particles having a yolk-shell structure composed of a shell portion having pores and a yoke portion provided in the receiving space of the shell portion (S400).

First, a precursor solution in which a precursor is dissolved in a solvent is prepared (S100). The precursor solution may be prepared by dissolving the precursor in a solvent, and the solvent may be water, and a plurality of precursors may be dissolved in the solvent.

The precursor may include at least one salt selected from the group consisting of acetate, nitrate, carbonate, chloride, hydroxide and oxide. . For example, two or more precursors having different compositions may be mixed and dissolved in the solvent, and the mixing ratio may be adjusted according to a desired composition or a preset ratio.

Next, a spray solution is prepared by adding a carbon compound to the precursor solution (S200). A spray solution may be prepared by dissolving a carbon-containing compound or carbon compound (or carbon source) containing carbon in the precursor solution, and at least a part of the carbon contained in the spray solution generates the catalyst particles by the carbon compound. In the process (S400) it can be burned by heating. Here, the carbon compound may include a sugar substance such as sucrose.

For example, a spray solution may be prepared by dissolving 0.25 M Manganese nitrate, 0.25 M cobalt nitrate, and 0.5 M sucrose in water. Through this, the spray solution containing a carbonizable material by a spray pyrolysis process or the like can be prepared.

Then, the spray solution is sprayed with droplets (S300). At this time, the spray solution may be sprayed through the ultrasonic droplet generator. The spray solution may be sprayed with droplets (fine water droplets) such as a humidifier by vibrators (or ultrasonic waves).

Then, heat is applied to the droplets to generate catalyst particles having a yoke-shell structure composed of a shell portion having pores and a yoke portion provided in the receiving space of the shell portion (S400). The droplets can be synthesized by partially solidifying (and/or drying) by heating, and a catalyst particle having a yoke-shell structure can be produced. As the carbon contained in the surface of the droplet is burned, the surface of the droplet may be dried and solidified by combustion energy, and combustion gas generated by combustion of the carbon may push the shell portion outward, and the liquid The inner part of the enemy is oxidized and contracted to form a yoke-shell structure. At this time, heat may be applied to the droplets in an oxidizing atmosphere such as an air atmosphere or an oxygen atmosphere so that the carbon can be burned. The process of applying heat to the droplets in this way can be referred to as a spray pyrolysis process.

Conventionally, the catalyst particles were synthesized and produced by a liquid phase process, but were not suitable for mass production because they consist of a multi-step process such as a deposition process, an etching process, and a water washing process. However, the spray pyrolysis process of the present invention is synthesized by heating the sprayed droplets to a high temperature, so that the catalyst particles are produced, it can be performed in a continuous process and has the advantage of being suitable for mass production.

For example, the droplets may be heated (or reacted) using air supplied at a flow rate of 10 L/min while moving the droplets to a tubular reactor having a length of about 1 m. Here, the tubular reactor may be a linear tubular shape, the droplets may be collected in a certain region, and the outer diameter may be larger than the inner diameter, so that the yoke-shell structure can be formed more effectively.

The catalyst particles of the yoke-shell structure have an empty space between the yoke part and the shell part, and have the advantage of a larger specific surface area than the normal hollow structure, and the reaction of the lithium-air battery because there is an empty space between the yoke part and the shell part. The product lithium oxide (eg, Li ₂ O ₂ ) may provide sufficient space for mass production.

The process of generating the catalyst particles (S400) may be performed by applying heat of 600 to 1,000°C to the droplets. For example, the process of generating the catalyst particles (S400) may be performed while heating by a high-temperature electric furnace surrounding the outside of the tubular reactor, and react the droplets at about 900 °C.

When the heating temperature is less than 600° C., the synthesis of catalyst particles is poorly achieved, and carbon is not well burned, making it difficult to form a yoke-shell structure. On the other hand, when the heating temperature is greater than 1,000° C., the combustion of carbon is made at once, and the combustion gas from the combustion of carbon is discharged from the inside to the outside at once to form a hollow structure, and the yoke remains inside. The yoke-shell structure does not form.

The process of generating the catalyst particles (S400) includes: providing heat to the droplets in an oxidizing atmosphere (S410); A process of burning carbon contained in the surface of the droplet (S420); A process in which the surface of the droplet is solidified by at least the combustion energy of carbon to form the shell (S430); And a step (S440) of shrinking the inner portion of the droplet to form the yoke portion separated from the shell portion.

In the oxidizing atmosphere, heat may be provided to the droplets (S410). Here, the oxidizing atmosphere refers to an atmosphere containing oxygen, and may be an air atmosphere or an oxygen atmosphere. Heat may be provided to the droplets in the oxidizing atmosphere so that carbon contained in the droplets can be burned.

Then, carbon contained in the surface of the droplet may be burned (S420). Since heat is applied to the surface of the droplet in an oxidizing atmosphere, carbon contained in the surface of the droplet can be instantaneously burned, and instantaneously high combustion energy can be generated. At this time, when the specific surface area of carbon exposed to oxygen decreases as the carbon is burned, combustion may be ended. In addition, an empty space may be formed in the portion in which the carbon is burned, and accordingly, pores may be formed in the shell portion, and the porous shell portion may be formed.

And the surface of the droplet is solidified by at least the combustion energy of carbon to form the shell portion (S430). High combustion energy can be instantaneously transferred to the surface of the droplet by combustion of carbon, and the surface of the droplet can be solidified by the combustion energy of carbon and/or thermal energy by heating, and the shell portion can be formed. have. Since the high combustion energy is transmitted only to the surface of the droplet, only the surface of the droplet can be solidified, and the solidification (or drying) speed of the surface of the droplet and the inside (or inside) of the droplet is different, so that the shell portion solidified quickly It can be separated from the inner portion of the droplet.

Then, the remaining droplets are contracted inside the shell portion to form the yoke portion separated from the shell portion (S440). The shell portion is formed on the surface of the droplet so that the remaining droplets can be located inside the shell portion, and heat is continuously applied to the remaining droplets so that the remaining droplets can contract within the shell portion. Heat may be continuously applied to the droplet, and the inner portion (ie, the remaining droplet) of the droplet separated from the shell portion may be contracted by solidification of the droplet surface (ie, formation of the shell portion), and synthesized. The yoke portion may be formed. For example, the inner portion of the droplet may shrink while being dried and solidified by the combustion energy of combustion of carbon contained in the inner portion (or central portion) of the droplet and/or the thermal energy of heating, and the combustion of the carbon may be reduced. Combustion gas generated through the expansion in the receiving space of the shell portion can provide a force (or pressure) in the direction in which the inner portion of the droplet is contracted, while the combustion gas in the receiving space passes through the pores of the shell portion The shell portion may be pushed outward. Here, the inner portion of the droplet may shrink as the precursor is oxidized by heat applied in an oxidizing atmosphere. Accordingly, the yoke portion separated from the shell portion may be formed, and through this, catalyst particles having a yoke-shell structure may be synthesized (or generated).

The process of generating the catalyst particles (S400) may further include a process of oxidizing the precursor (S445) by heating in an oxidizing atmosphere.

The precursor may be oxidized by heating in an oxidizing atmosphere (S440). As the precursor contained in the droplet is oxidized by heating, the inner portion (or central portion) of the droplet may be contracted. At this time, the process in which the precursor is oxidized (S445) may be performed immediately after the process of forming the shell (S430), and heat may be continuously provided to start combustion of carbon contained in the inside of the droplet.

On the other hand, in the process of forming the yoke (S440), the carbon contained in the inner part of the droplet may be sequentially burned and turned off according to the supply of oxygen in the accommodation space (or due to lack of oxygen), and carbon that is burned and turned off By the stepwise combustion of the inner portion of the droplet (ie, the yoke portion) may be contracted.

The process of generating the catalyst particles (S400) may further include a process of synthesizing the oxide of the precursor (S450).

And the oxide of the precursor may be synthesized (S450). Through this, the catalyst particles may be synthesized, and the catalyst particles may be generated. For example, the catalyst particles may have a composition of MnCo ₂ O ₄ .

In this way, the shell portion is formed by instantaneous solidification of the droplet surface by combustion of carbon contained in the surface of the droplet, and the yoke portion and the shell portion may be separated from each other by contraction of the inner portion of the droplet by oxidation of the precursor. The yoke-shell structure can be formed, and the yoke-shell structured catalyst particles can be synthesized.

The molar concentration of the precursor solution in the spray solution may be 0.02 to 1 M. When the molar concentration of the precursor solution is less than 0.02 M, the portion serving as a catalyst is reduced, so that lithium oxide cannot be generated and decomposed smoothly when produced as an air electrode, and an overvoltage is generated during charging and discharging of a lithium-air battery. It cannot be lowered. On the other hand, when the molar concentration of the precursor solution is greater than 1 M, the molar concentration of the carbon compound is relatively small, and the combustion energy of carbon for forming the shell portion by the instantaneous solidification of the droplet surface is determined by Failure to provide to the surface makes it impossible to produce (or synthesize) the catalyst particles in a yoke-shell structure.

The molar concentration of the carbon compound in the spray solution may be 0.02 to 1 M. When the molar concentration of the carbon compound is greater than 1 M, the proportion of the precursor that acts as a catalyst decreases and lithium oxide cannot be generated and decomposed smoothly when produced as an air electrode, and charging and discharging of a lithium-air battery When the overvoltage cannot be lowered. On the other hand, when the molar concentration of the carbon compound is less than 0.02 M, the molar concentration of the carbon compound becomes too small, and the combustion energy of carbon for forming the shell portion by the instantaneous solidification of the droplet surface is the surface of the droplet. The catalyst particles in the yoke-shell structure cannot be produced.

The catalyst particles may be made of an oxide containing at least one of Fe, Co, Mn and Ni. For example, the catalyst particles may have a composition selected from the group consisting of Fe ₂ O ₃ , Co ₃ O ₄ , Mn ₂ O ₃ , CoMn ₂ O ₄ , NiCo ₂ O ₄ , CoFe ₂ O ₄ , and NiO. . That is, the catalyst particles may be Fe ₂ O ₃ , Co ₃ O ₄ , Mn ₂ O ₃ , CoMn ₂ O ₄ , NiCo ₂ O ₄ , CoFe ₂ O ₄ , and oxides of NiO, etc. When the catalyst particles are used in a cathode for a lithium-air battery, lithium (ion) and air can be promoted to facilitate lithium oxide production and decomposition.

As described above, in the present invention, the catalyst particles are composed of a shell portion having pores and a yoke portion provided in the receiving space of the shell portion, and thus have a yoke-shell structure that forms an empty space between the shell portion and the yoke portion, so that the specific surface area is smaller than that of a general spherical catalyst particle This may increase, and when used in a cathode for a lithium-air battery, the space between the shell and the yoke may provide a space for mass production of lithium oxide, a reaction product of the lithium-air battery. The lithium-air battery including the cathode catalyst made of the catalyst particles can increase the catalytically active area of the catalyst particles, thereby improving the reactivity of the cathode catalyst, thereby increasing the battery capacity. In addition, the method for manufacturing an anode catalyst for a lithium-air battery can produce a catalyst having a yoke-shell structure by generating catalyst particles through a spray pyrolysis process using droplets of a spray solution containing a precursor and a carbon compound. Lithium-air battery comprising an air cathode made of a catalyst can exhibit a high capacity, and can realize a lithium-air battery having excellent cycle characteristics.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the above-described embodiments, and general knowledge in the field to which the present invention pertains without departing from the gist of the present invention claimed in the claims Anyone who has a will understand that various modifications and other equivalent embodiments are possible. Therefore, the technical protection scope of the present invention should be defined by the following claims.

100: catalyst particles 110: shell portion
111: accommodation space 112: pore
120: York section

Claims (12)

A shell part surrounding the accommodation space and having pores forming a flow path; And
Catalyst particles comprising a; yoke portion provided to be spaced at least partially from the inner surface of the receiving space of the shell portion. The method according to claim 1,
The shell portion and the yoke portion are catalyst particles made of the same material. The method according to claim 1,
The volume of the yoke portion is smaller than the volume of the receiving catalyst particles. The method according to claim 1,
The shell portion and the yoke portion are catalyst particles made of oxides containing at least one of Fe, Co, Mn, and Ni. An anode comprising an anode catalyst made of the catalyst particles of any one of claims 1 to 4;
A lithium electrode disposed in correspondence with the air electrode and including lithium metal;
A separator provided between the air electrode and the lithium electrode; And
Lithium-air battery comprising; electrolyte for electrically connecting the air electrode and the lithium electrode. Preparing a precursor solution in which the precursor is dissolved in a solvent;
Preparing a spray solution by adding a carbon compound to the precursor solution;
Spraying the spray solution with droplets; And
Method of producing a cathode catalyst for a lithium-air battery comprising; applying heat to the droplets to generate catalyst particles of a yoke-shell structure consisting of a shell portion having pores and a yoke portion provided in the receiving space of the shell portion. The method according to claim 6,
The process of generating the catalyst particles,
Providing heat to the droplets in an oxidizing atmosphere;
A process in which carbon contained in the surface of the droplet burns;
A process in which the surface of the droplet is solidified by at least the combustion energy of carbon to form the shell portion; And
A method of manufacturing an air cathode catalyst for a lithium-air battery, comprising the step of forming the yoke portion separated from the shell portion by shrinking the remaining droplets inside the shell portion. The method according to claim 6,
The precursor is lithium-containing at least one salt selected from the group consisting of acetate, nitrate, carbonate, chloride, hydroxide and oxide- Method for manufacturing a cathode catalyst for an air battery. The method according to claim 6,
A method for preparing a cathode catalyst for a lithium-air battery having a molar concentration of the precursor solution in the spray solution of 0.02 to 1 M. The method according to claim 6,
A method for preparing an anode catalyst for a lithium-air battery, wherein the molar concentration of the carbon compound in the spray solution is 0.02 to 1 M. The method according to claim 6,
The process of generating the catalyst particles is performed by applying heat of 600 to 1,000°C to the droplets, a method of manufacturing an anode catalyst for a lithium-air battery. The method according to claim 6,
The catalyst particles are Fe, Co, Mn and a cathode catalyst manufacturing method for a lithium-air battery made of an oxide containing at least one of Ni.

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