KR20170089312A - Silicon carbide composite, method of fabricating the same and power strage divice - Google Patents

Abstract

According to an embodiment of the present invention, a silicon carbide composite comprises: a core comprising silicon carbide; and a shell which encircles the core. The shell has an overall uniform thickness. According to an embodiment of the present invention, a method for manufacturing a silicon carbide composite comprises the following steps: forming a silicon carbide core by combining a carbon source and a silicon source; and forming a shell on a surface of the silicon carbide core. The step of forming the shell comprises deposition of carbon in an overall uniform thickness on the surface of the silicon carbide core. According to an embodiment of the present invention, an electricity storage device comprising the silicon carbide composite comprises: a positive electrode and a negative electrode; and electrolyte between the positive electrode and the negative electrode. The positive electrode and the negative electrode comprise substrates and electrode layers on the substrates. The electrode layer comprises the core and the shell encircling the core. The shell has an overall uniform thickness. The present invention is to provide the silicon carbide composite with an increased specific surface area.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a silicon carbide composite, a method of manufacturing the same, and an electric storage device including the silicon carbide composite,

Embodiments relate to a silicon carbide composite, a method of manufacturing the same, and an electric storage device including the same.

Silicon carbide powder has recently been used as a semiconductor material for various electronic devices and purposes. Silicon carbide powders are particularly useful due to their physical strength and high resistance to chemical attack. Silicon carbide powders can also be used in a variety of applications including, but not limited to, radiation hardness, a relatively wide bandgap, a high saturated electron drift velocity, a high operating temperature, and blue, violet, and ultraviolet Quot;) < / RTI > region.

The silicon carbide powder may be produced by a variety of methods, for example, the Acheson method, the carbon thermal reduction method, the liquid polymer thermal decomposition method, or the CVD method. Particularly, the high-purity silicon carbide powder synthesis method uses a liquid phase polymer decomposition method or a carbon thermal reduction method.

The silicon carbide powder may be used alone or in combination with other materials to form a silicon carbide composite. The silicon carbide composite may be applied to electrode layers of various electric storage devices such as supercapacitors and ultracapacitors.

At this time, when applied to such an electrode layer, the specific surface area or the like may be an important factor for determining the efficiency and storage capacity of the electric storage device.

Accordingly, there is a demand for a silicon carbide composite having an improved specific surface area.

The embodiments are directed to a silicon carbide composite having improved specific surface area, a method of manufacturing the same, and an electric storage device including the same.

A silicon carbide composite according to an embodiment includes: a core comprising silicon carbide; And

And a shell surrounding the core, wherein the shell has a generally uniform thickness.

A method of manufacturing a silicon carbide composite according to an embodiment includes: forming a silicon carbide core by synthesizing a carbon source and a silicon source; And forming a shell on the surface of the silicon carbide core, wherein forming the shell comprises depositing a substantially uniform thickness of carbon on the surface of the silicon carbide core.

An electric storage device including a silicon carbide composite according to an embodiment includes: a positive electrode and a negative electrode; And an electrolyte between the positive electrode and the negative electrode, wherein the positive electrode and the negative electrode comprise: a substrate; A core comprising an electrode layer on the substrate, the electrode layer comprising silicon carbide; And a shell surrounding the core, wherein the shell has a generally uniform thickness.

The silicon carbide composite according to an embodiment may have a shell having a uniform overall thickness throughout the silicon carbide core.

The method of making a silicon carbide composite according to an embodiment may include depositing a carbon as a whole uniform thickness on the surface of the silicon carbide core.

Since the electric storage device including the silicon carbide composite according to the embodiment includes the uniform thickness of the shell surrounding the silicon carbide core, the specific surface area can be increased and thus the electric capacity can be improved, Can be implemented.

1 is a cross-sectional view of a silicon carbide composite formed according to a conventional chemical vapor deposition method.
2 is a cross-sectional view of a silicon carbide composite according to an embodiment.
3 is an enlarged view of a cross section of a silicon carbide composite according to an embodiment.
FIG. 4 is a flowchart showing a process for producing a silicon carbide composite according to an embodiment.
5 is a cross-sectional view of an electric storage device to which the silicon carbide composite according to the embodiment is applied.
6 is a cross-sectional view of a positive electrode of an electric storage device to which the silicon carbide composite according to the embodiment is applied.

In the description of the embodiments, it is to be understood that each layer (film), area, pattern or structure may be referred to as being "on" or "under / under" Quot; includes all that is formed directly or through another layer. The criteria for top / bottom or bottom / bottom of each layer are described with reference to the drawings.

The thickness or the size of each layer (film), region, pattern or structure in the drawings may be modified for clarity and convenience of explanation, and thus does not entirely reflect the actual size.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, the silicon carbide composite formed according to the conventional chemical vapor deposition method may include a silicon carbide core 100 'and a shell 200' surrounding the silicon carbide core 100 '.

In the chemical vapor deposition method, silicon carbide may be disposed in the reaction chamber 300, and the carbon source may be introduced into the reaction chamber in an inert atmosphere together with argon gas (Ar).

And a shell 200 'surrounding the silicon carbide core 100' and the silicon carbide core 100 'as the carbon source is deposited on the surface of the silicon carbide.

At this time, the carbon source and the argon gas injected into the reaction chamber can move in the horizontal direction. As a result, there is a problem that the silicon carbide particles are not uniformly deposited by the carbon source.

That is, since the carbon source and the argon gas move in the horizontal direction, the shell 200 'surrounding the silicon carbide particles, that is, the silicon carbide core 100' It can be thick.

For example, the silicon carbide particles disposed in the reaction chamber 300 may contact the lower surface of the reaction chamber 300. The contact portion C1 between the silicon carbide particle and the reaction chamber may be difficult to be exposed to the carbon source and the argon gas. Accordingly, the thickness of the contact portion C1 between the silicon carbide particle and the reaction chamber may be thin or the shell may not be disposed.

For example, the silicon carbide particles disposed in the reaction chamber 300 may contact each other. The contact portion C2 of the silicon carbide particles may be difficult to be exposed to the carbon source and the argon gas. Accordingly, the contact portion C2 of the silicon carbide particles may have a thin shell or no shell.

The embodiment is intended to solve the problem that the specific surface area is reduced according to the anisotropic deposition of the shell formed by chemical vapor deposition (CVD), and the electric capacity of the electric storage device formed by such a method is lowered.

Referring to FIGS. 2 and 3, the silicon carbide composite according to an embodiment may include a core 100 and a shell 200.

The core 100 may include carbon and silicon. In detail, the core 100 may include silicon carbide (SiC). For example, the core 100 may include at least one of silicon carbide and alpha phase silicon carbide.

The core 100 may have a spherical shape. However, the embodiment is not limited thereto, and it is needless to say that the core 100 may be formed in various shapes such as a polygonal shape such as a triangle, a quadrangle, and the like, a circle, and an ellipse.

The particle size of the core 100 may be several micrometers (占 퐉) to several tens of micrometers (占 퐉). For example, the particle size of the core 100 may range from about 1 [mu] m to about 100 [mu] m. For example, the particle size of the core 100 may range from about 1 [mu] m to about 50 [mu] m. For example, the particle size of the core 100 may be about 1 [mu] m to about 30 [mu] m.

When the size of the core 100 is less than about 1 탆, the overall density of the silicon carbide composite is reduced, so that the capacity per unit volume can be lowered when the silicon carbide composite is applied to an electric storage device. In addition, when the size of the core 100 is more than about 100 mu m, when the silicon carbide composite is applied to the electrode layer, the conductivity may be lowered.

The shell 200 may be disposed on the core 100. For example, the shell 200 may be disposed around the core 100. In detail, the shell 200 may surround the core 100 and be integrally disposed on the core 100.

The shell 200 may be disposed in contact with the core 100. That is, the core 100 and the shell 200 form an interface and can be in contact with each other. For example, the shell 200 may be physically and / or chemically contacted with the core 100.

The shell 200 may include a material different from the core 100. In detail, the shell 200 may include carbon (C).

The shell 200 may be formed in a spherical shape. The shell 200 may be formed in a shape corresponding to the core 100 as the core 100 is uniformly deposited on the surface of the core 100 regardless of the shape of the core 100.

At least one of the core 100 and the shell 200 may include a plurality of pores. For example, pores P may be formed in the shell 200. That is, the shell 200 may have a porous structure.

The size of the pores of the shell 200, that is, the diameter of the pores may be 1 nm or less. For example, the size of the pores of the shell 200 may be 0.5 nm to 1 nm. For example, the size of the pores of the shell 200 may include 0.7 nm to 0.8 nm.

For example, by controlling the size of the pores of the shell 200 to be 1 nm or less, the specific surface area can be maximized.

The specific surface area of the core (100) and the specific surface area of the shell (200) may be different.

In detail, the specific surface area of the shell 200 may be larger than the specific surface area of the core 100. That is, the specific surface area of the shell 200 having a porous structure can be increased by pores, and thus the specific surface area of the shell 200 can be larger than the specific surface area of the core 100.

The density of the core 100 and the density of the shell 200 may be different.

In detail, the density of the core 100 may be greater than the density of the shell 200. That is, the density of the core 100 including silicon carbide may be greater than the density of the shell 200 containing carbon.

The molecular weight of the core (100) and the molecular weight of the shell (200) may be different.

In detail, the molecular weight of the core 100 may be greater than the molecular weight of the shell 200. That is, the molecular weight of the core 100 containing silicon carbide may be larger than the molecular weight of the shell 200 containing carbon.

The core 100 and the shell 200 may have a constant weight ratio. The weight ratio of the core 100 to the shell may be from about 2: 8 to about 8: 2. In detail, the core 100 may comprise from about 20% to about 80% by weight of the total silicon carbide composite.

When the weight ratio of the core 100 is less than about 20% by weight based on the total of the silicon carbide composite, the overall density of the silicon carbide composite is reduced, so that when the silicon carbide composite is applied to an electric storage device, have.

In addition, when the weight ratio of the core 100 to the entire silicon carbide composite exceeds about 80% by weight, that is, when the weight ratio of the shell 200 is less than about 20% by weight, the specific surface area of the silicon carbide composite , So that when the silicon carbide composite is applied to an electric storage device, the capacity per unit volume can be lowered.

The shell 200 may have a uniform overall thickness. For example, the thickness of the shell 200 may be less than 1%. For example, the thickness of the shell 200 may be less than 0.8%. For example, the thickness of the shell 200 may be less than 0.7%. Here, the " thickness " may mean the shortest distance from the surface of the core 100, that is, the interface between the core 100 and the shell 200 to the surface of the shell 200.

That is, the shell 200 may have a thickness deviation less than 1% according to a measured position at an arbitrary position.

Referring to FIG. 3, the thickness of the shell 200 may be measured in the upward, downward, leftward, rightward, or 0 °, 90 °, 180 °, and 270 ° directions.

For example, the thickness measured in the upper portion of the shell 200 or in the 0 ° direction is the thickness measured in the right side of the shell 200 or 90 °, Position, or the thickness measured in the direction of 180 degrees and the thickness measured in the position of the left side of the shell 200 or in the direction of 270 degrees. The " correspond " herein may include the same or similar thickness of the shell 200, and a similar range may be that the thickness deviation is less than 1%.

The distance D1 from the first point I1 on the surface of the core 100 to the first point S1 on the surface of the shell 200 is greater than the distance D1 between the first point I1 on the surface of the core 100 and the second point S1 on the surface of the core 100 A distance D2 from a second point on the surface of the shell 200 to a second point S2 on the surface of the shell 200 from a third point I3 on the surface of the core 100, And the distance D4 from the fourth point I4 on the surface of the core 100 to the fourth point S4 on the surface of the shell 200 have. Here, the distance may mean the shortest distance connecting one point on the surface of the core and one point on the surface of the shell.

However, the embodiment is not limited thereto, and the first to fourth points may be measured at an arbitrary position or an arbitrary direction. It goes without saying that the thickness of the shell can be measured at any position or any direction including the fifth point, the sixth point, etc. above the first to fourth points.

A silicon carbide composite according to an embodiment includes a core comprising silicon carbide and a shell surrounding the core, wherein the shell may have a uniform overall thickness. In detail, the thickness deviation of the shell may include less than 1%. Accordingly, when the silicon carbide composite according to the embodiment is applied to an electrode material, the specific surface area of the silicon carbide composite can be increased. Accordingly, when the silicon carbide composite according to the embodiment is applied to an electrode material to be used in an electric storage device or the like, the electric capacity of the electric storage device can be improved.

Hereinafter, a method of manufacturing the silicon carbide composite according to the embodiment will be described with reference to FIG.

Referring to FIG. 4, a method of manufacturing a silicon carbide composite according to an embodiment includes: (ST10) forming a silicon carbide core by synthesizing a carbon source and a silicon source; And forming a shell on the surface of the silicon carbide core (ST20).

In step ST10 of forming the silicon carbide core by synthesizing the carbon source and the silicon source, silicon carbide particles or silicon carbide crystals can be formed.

The carbon source may comprise a solid carbon source or an organic carbon compound.

Examples of the solid carbon source include graphite, carbon black, carbon nano tube (CNT), and fullerene (C ₆₀ ).

Examples of the organic carbon compound include ethanol, methanol, penol, franc, xylene, polyimide, polyunrethane, polyvinyl alcohol, Polyacrylonitrile, or poly (vinyl acetate), and the like. In addition, cellulose, sugar, pitch, tar and the like can be used.

The silicon source may include various materials capable of providing silicon. For example, the silicon source may comprise silica. In addition to the silica, the silica source may be silica powder, silica sol, silica gel, quartz powder, or the like. However, the embodiment is not limited thereto, and an organosilicon compound containing silicon may be used as a silicon source.

The step (ST10) of synthesizing the carbon source and the silicon source to form the silicon carbide core may react the carbon source and the silicon source.

In detail, after the silicon source such as the silicon powder is disposed in the reaction chamber, the carbon source can be introduced into the chamber in an inert atmosphere together with argon gas (Ar) or the like at a temperature of about 1200 ° C to about 1400 ° C. Accordingly, the carbon source is carbonized while being injected into the chamber, and the carbon source may be converted into a carbon crystal structure such as graphite, graphene, or a carbon nano tube.

Then, the process temperature was raised to a temperature of about 1300 ° C to about 1900 ° C, and then the carbon source and the silicon source were reacted.

By this reaction, silicon carbide can be formed by the whole reaction formula of Reaction Formula 3 according to the following Reaction Schemes 1 and 2.

[Reaction Scheme 1]

_{SiO 2 (s) + C (} s) -> SiO (g) + CO (g)

[Reaction Scheme 2]

SiO (g) + 2C (s) - > SiC (s) + CO (g)

[Reaction Scheme 3]

_{SiO 2 (s) + 3C (} s) -> SiC (s) + 2CO (g)

Further, the silicon carbide may have a particle diameter of about 1 탆 to about 10 탆. In order to form the silicon carbide, waste silicon wafers generated in a semiconductor manufacturing process can be used. Accordingly, silicon carbide having various particle diameters can be formed.

Subsequently, a step (ST20) of forming a shell on the surface of the silicon carbide core may be performed. That is, the shell may be formed on the surface of the silicon carbide core produced in step ST10. In detail, the porous carbon can be deposited on the surface of the silicon carbide core.

In detail, the silicon carbide prepared in the preceding step is placed in the reaction chamber, and the carbon source together with argon gas (Ar) and the like can be introduced into the chamber in an inert atmosphere together with argon gas (Ar) or the like in an inert atmosphere. At this time, in order to form pores in the shell, oxygen (O ₂ ) gas together with a carbon source and nitrogen (N ₂ ) gas may be added together to improve electrical conductivity.

By this reaction, a shell containing carbon by the carbon source can be deposited on the surface of the silicon carbide core.

The step of forming the shell may be conducted at a temperature of about 900 ° C to about 1000 ° C.

If the shell is formed at a temperature below about 900 ° C, the temperature is too low to allow the carbon source to be difficult to deposit on the surface of the silicon carbide core.

The step of forming the shell may comprise depositing an overall uniform thickness of carbon on the surface of the silicon carbide core. For example, the shell may be deposited to a uniform thickness by fluidized bed chemical vapor deposition.

Referring to FIG. 2, in the step of forming the shell, silicon carbide may be separated from the reaction chamber 300. That is, silicon carbide may not contact the reaction chamber. In detail, in the step of forming the shell, the carbon source and the argon gas injected into the reaction chamber 300 can move in the vertical direction. Accordingly, the silicon carbide particles can be deposited with a uniform thickness regardless of the position or direction by the carbon source moving in the vertical direction, argon gas, or the like.

More specifically, in the step of forming the shell, the silicon carbide core can be rotated by a carbon source moving in a vertical direction, argon gas, or the like.

That is, the carbon source can be deposited while the rotation of the silicon carbide core is caused by the flow. Accordingly, since the carbon shell can be formed on the silicon carbide core to have a uniform thickness as a whole, the isotropic deposition of the shell can be performed regardless of the shape of the silicon carbide core.

In addition, unlike the chemical vapor deposition method in which a shell is formed in a uniform and thin layer, the formation of a shell according to the fluidized bed chemical vapor deposition method makes the silicon carbide flow, so that the bulk silicon carbide composite can be easily synthesized.

Further, a shell having a uniform thickness or a corresponding thickness can be formed regardless of the grain size of the silicon carbide.

Further, the porosity per volume can be increased by controlling the ratio of the size of the silicon carbide core and the shell.

Hereinafter, an electric storage device to which the silicon carbide composite according to the embodiment is applied will be described with reference to FIGS. 5 and 6. FIG.

5 and 6, the electric storage device according to the embodiment may include a positive electrode and a negative electrode, an electrolyte disposed between the positive electrode and the negative electrode, and a separator.

The anode electrode and the cathode electrode may include a substrate 10 and an electrode layer 20 on the substrate 10. The silicon carbide composite according to the embodiment may be applied to the electrode layer 20.

The substrate 10 may comprise a metal. In detail, the substrate 10 may include aluminum (Al), copper (Cu), nickel (Ni), or an alloy thereof.

In detail, the electrode layer 20 may be formed by printing or vapor-depositing an electrode material in which a silicon carbide composite and a binder are mixed on the substrate 10. The electrode layer 20 may be formed on the substrate 10 to a thickness of about 100 탆 to about 500 탆.

The binder includes at least one binder selected from the group consisting of PVDF, PTFE, carboxymethyl cellulose (CMC), and styrene-butadiene rubbe (SBR) as a material for printing or depositing the silicon carbide composite on the substrate can do.

Referring to FIG. 6, the electrode layer 20 may be disposed on the substrate 10 at a thickness (T) of about 100 μm to about 300 μm. When the thickness of the electrode layer 20 is less than about 100 μm The conductivity of the electrode layer may be deteriorated and the overall size of the electric storage device may be increased when the thickness of the electrode layer 20 is greater than about 300 mu m.

The electrode layer 20 may further include a conductive material. The conductive material may serve to smooth the movement of electrons in the electrode layer. However, the embodiment is not limited to this, and the electrode layer 20 does not include a conductive material, and the silicon carbide composite may serve as a conductive material.

An electrolyte 30 and a separator 40 for preventing contact between the positive electrode 21 and the negative electrode 22 may be disposed between the positive electrode 21 and the negative electrode 22.

When the silicon carbide composite according to the embodiment is applied to an electrode material, the specific surface area can be improved. For example, as the shell having pores on the surface of the silicon carbide core is formed, the area of the silicon carbide composite contacting the substrate can be improved when the electrode material is disposed on the substrate or the like.

That is, as the carbon containing pores is formed in the shell, the overall specific surface area of the silicon carbide composite can be improved. For example, the specific surface area of the silicon carbide composite may be from 1700 m 2 / g to 4000 m 2 / g.

Accordingly, when the silicon carbide composite according to the embodiment is applied to an electric storage device such as a supercapacitor or an ultracapacitor, the electric capacity can be improved by the improved specific surface area, so that a large-capacity electric storage device can be realized.

Also, by adjusting the particle diameter of the silicon carbide core and the thickness of the carbon shell, the density of the electrode including the silicon carbide composite can be improved to 0.6 g / cm 3 or more. That is, by adjusting the particle diameter of the silicon carbide core and the thickness of the carbon shell, the filling density of the silicon carbide composite can be increased, and the density of the electrode including the silicon carbide composite can be improved to 0.6 g / cm 3 or more have.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments may be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

Claims (13)

A core comprising silicon carbide; And
And a shell surrounding the core,
Wherein the shell has an overall uniform thickness. The method according to claim 1,
Wherein a distance from a first point on a surface of the core to a first point on a surface of the shell is greater than a distance from a second point on a surface of the core to a second point on a surface of the shell, The distance to a third point on the surface of the shell and the fourth point on the surface of the core to the fourth point on the surface of the shell. The method according to claim 1,
Wherein the core comprises a spherical shape. The method according to claim 1,
Wherein the shell comprises a different material from the core,
Wherein the shell comprises carbon. 2. The silicon carbide composite of claim 1, wherein at least one of the core and the shell comprises a plurality of pores. 6. The method of claim 5,
Wherein the pore size of the shell is 1 nm or less. Synthesizing a carbon source and a silicon source to form a silicon carbide core; And
Forming a shell on the surface of the silicon carbide core,
Wherein forming the shell comprises depositing an overall uniform thickness of carbon on the surface of the silicon carbide core. 8. The method of claim 7,
Wherein the step of forming the shell proceeds at a temperature of 900 ° C to 1000 ° C. 8. The method of claim 7,
Wherein a plurality of pores are formed in at least one of the core and the shell. 8. The method of claim 7,
The carbon source may be selected from the group consisting of graphite, carbon black, carbon nano tube (CNT), fullerene (C ₆₀ ), methanol, ethanol, phenol, polyolefins such as xylene, polyimide, polyunrethane, polyvinyl alcohol, polyacrylonitrile, poly (vinyl acetate), cellulose, sugar, A method of making a silicon carbide composite comprising a pitch or tar. 8. The method of claim 7,
Wherein the silicon source comprises silica, silica powder, silica sol, silica gel or quartz powder. An anode electrode and a cathode electrode; And
And an electrolyte between the anode electrode and the cathode electrode,
The positive electrode and the negative electrode may be made of,
Board;
And an electrode layer on the substrate,
Wherein the electrode layer comprises the silicon carbide composite according to any one of claims 1 to 6. 13. The method of claim 12,
Wherein the specific surface area of the silicon carbide composite is from 1700 m < 2 > / g to 4000 m < 2 > / g.

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