KR20170094016A - Method of manufacturing anode for lithium ion battery using tin sulfide and lithium ion battery - Google Patents

Abstract

Provided are a method for manufacturing an anode for a lithium ion battery using tin sulfide, the method comprising the following steps: preparing a positive electrode current collector for a lithium ion secondary battery; etching one surface of the current collector to form a concavo-convex structure having recesses and convex portions on one surface of the current collector; and laminating a tin sulfide layer on the current collector. According to the present invention, by using tin sulfide as the anode, the corrosion resistance against an electrolyte can be enhanced. Further, by forming the tin sulfide in a columnar structure, it is possible to minimize a volume change due to charging and discharging. Therefore, it is possible to provide the anode for a lithium ion battery having high lifetime and high reliability. Further, by using tin sulfide as the anode, the production cost can be reduced, and the lithium ion battery having high efficiency with respect to costs can be provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for manufacturing an anode for a lithium ion battery using tin sulfide and a lithium ion battery,

The present invention relates to an electrode manufacturing method, and more particularly, to a method of manufacturing an anode for a lithium ion battery.

Recently, as the use of portable electronic products increases, battery usage is increasing. Particularly, the performance of portable electronic products is increasing, and a lot of power is required to operate them. Therefore, the demand for rechargeable batteries which can be recharged many times is increasing, because the rechargeable batteries can not be recharged and the amount of rechargeable batteries required for recycling is reduced.

A secondary battery refers to a battery which is semi-permanently usable by charging the generated electricity by causing an oxidation-reduction reaction between the anode and the cathode using the power supplied from the outside. The rechargeable battery is divided into a nickel battery, a polymer battery, a lithium polymer battery, a lithium sulfide battery, and a lithium ion battery depending on the type of the charging material. Following the emergence of nickel-cadmium batteries and nickel-metal hydride batteries in the 1980s, lithium-based secondary batteries appeared in the 1990s, and lithium-polymer batteries have been introduced since the 2000s.

In particular, the market size of lithium-ion batteries is so large that it accounts for most of the rechargeable battery market. Lithium ion batteries are lighter in weight and are advantageous for making high capacity batteries. In addition, since the energy density is high, the memory effect is not provided, and the degree of natural discharge is small even when not in use, it is widely used in batteries such as portable telephones and electronic products.

These lithium ion batteries are mainly composed of a carbon-based anode, an organic electrolyte, and a lithium oxide cathode. During the charge using the chemical reaction, the lithium ions are discharged from the cathode and moved to the carbon-based anode through the electrolyte. The discharging process is carried out through the carbon-based anode Lithium ion escapes and moves to the cathode. At this time, the voltage, lifetime, capacity, stability and the like of the battery can be greatly changed depending on what kind of materials are used.

However, the lithium ion battery has a problem that corrosion of the anode may occur due to an electrolyte having a function of facilitating the movement of lithium ions.

In addition, when lithium ions come out from or enter the anode, the electrode is broken due to the change in volume, and the electrode capacity and the number of charge / discharge cycles are reduced.

An object of the present invention is to provide an anode for a lithium ion battery having high corrosion resistance against an electrolyte.

Another object of the present invention is to provide a method of manufacturing an anode for a lithium ion battery capable of minimizing a volume change due to charge and discharge.

According to an aspect of the present invention, there is provided a method of manufacturing an anode for a lithium ion battery. The method for manufacturing an anode includes the steps of preparing a current collector, etching a surface of the current collector to form a concavo-convex structure having recesses and convex portions on one surface of the current collector, And laminating the layers.

In the step of depositing the tin sulfide layer on the current collector, the tin sulfide layer may be deposited on the uneven structure using atomic layer deposition.

The tin sulfide layer may be formed by stacking a plurality of single atom layers.

The convex portion of the current collector may have a columnar structure.

According to another aspect of the present invention, there is provided a lithium ion battery. The lithium ion battery may include an anode, a cathode, and an electrolyte between the anode and the cathode, the current collector having a concave-convex structure having recesses and protrusions on the surface, and a tin sulfide layer stacked on the concave- .

The convex portion of the current collector may have a columnar structure.

The tin sulfide layer may be a plurality of single-element layers.

The tin sulfide layer may be composed of tin sulfide or tin disulfide.

The tin sulfide layer may be a crystalline hexagonal structure.

According to the present invention, by using tin sulphide as the anode, the corrosion resistance against the electrolyte can be enhanced. Further, by forming the above-described tin sulfide in a columnar structure, it is possible to minimize volume change due to charging and discharging. Therefore, it is possible to provide an anode for a lithium ion battery having a high life and high reliability.

Further, by using tin sulfide as the anode, the production cost can be reduced, and a lithium ion battery with high efficiency can be provided.

The technical effects of the present invention are not limited to those mentioned above, and other technical effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 is a schematic view showing a method of manufacturing an anode for a lithium ion battery according to a first embodiment of the present invention.
2 is a schematic view showing a method of manufacturing an anode for a lithium ion battery according to a second embodiment of the present invention.
3 is a schematic diagram showing a lithium ion battery using an anode according to the first embodiment of the present invention.

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

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. Rather, the intention is not to limit the invention to the particular forms disclosed, but rather, the invention includes all modifications, equivalents and substitutions that are consistent with the spirit of the invention as defined by the claims.

It will be appreciated that when an element such as a layer, region or substrate is referred to as being present on another element "on," it may be directly on the other element or there may be an intermediate element in between .

1 is a schematic view showing a method of manufacturing an anode for a lithium ion battery according to a first embodiment of the present invention. 2 is a schematic view showing a method of manufacturing an anode for a lithium ion battery according to a second embodiment of the present invention.

1A and 2A, a current collector 100 may be prepared. The current collector 100 may be a metallic material. For example, the current collector 100 may be platinum, aluminum or copper, but is not limited thereto.

1B and 2B, a current collector 100 is formed by etching a surface of the current collector 100 to have concave-convex structures 111 and 121 having concave portions 111a and 121a and convex portions 111b and 121b. can do. For example, the convex portions 111b and 121b of the current collector 100 having the concave and convex structures 111 and 121 may have a triangular shape (FIG. 2B) or a columnar shape having a predetermined diameter. For example, the current collector 110 of the concavoconvex structure may have a columnar structure (FIG. 1B)

Photolithography and dry etching may be used to form the concave-convex structures 111 and 121, specifically concave and convex structures of the columnar structure (111 in FIG. 1B). Alternatively, a blasting method, specifically sandblasting, may be used as a method of forming the concave-convex structures 111 and 121, specifically, the concave-convex structure of the triangular shape (121 of FIG. 2B) .

Referring to FIGS. 1C and 2C, tin sulfide layers 210 and 220 may be deposited on the concave and convex structures 111 and 121 of the current collector 100. The tin sulfide layers 210 and 220 may be formed in a concave-convex structure along the shape of the concave-convex structures 111 and 121 of the current collector 100. The tin sulfide layers 210 and 220 may be tin sulphide (SnS) or tin disulphide (SnS ₂ ).

The tin sulfide layers 210 and 220 may be deposited using atomic layer deposition (ALD). That is, the tin sulfide layers 210 and 220 may be formed using a precursor including tin (Sn) 230 and a precursor including sulfur (S) 240. For example, the precursor including the tin (Sn) 230 may be TDPAS (Tetrakis (dimethylamino) Tin) and the precursor including the sulfur (S) 240 may be hydrogen sulfide (H ₂ S).

The tin sulfide layers 210 and 220 provide a precursor including the tin 230 on the current collector 100 having the concave and convex structures 111 and 121 and purge the precursor including the tin 230, And providing a precursor comprising the sulfur (240) on a current collector (100) having the uneven structure (111, 121) and purge the precursor comprising the sulfur (240) May be formed by a unit process. For example, when the unit process is performed once, a mono-element layer of the tin sulfide layer may be formed.

At this time, the deposition of the tin sulfide layers 210 and 220 may be performed at a temperature of 140 ° C to 150 ° C. In this case, the tin sulfide layers 210 and 220 may be a tin disulphide layer (SnS ₂ ) having a crystalline two-dimensional hexagonal structure.

The tin sulfide layers 210 and 220 may be formed by stacking the mono-element layer or the plurality of mono-element layers. That is, the thickness of the tin sulfide layers 210 and 220 can be controlled by adjusting the number of the monolayer layers. For example, the thickness of the tin sulfide layers 210 and 220 may be 1 nm to 1 μm.

Thus, the anode 300 for a lithium ion battery including the tin sulfide layers 210 and 220 can be formed. Since the tin sulfide layers 210 and 220 formed on the concavo-convex structures 111 and 121 have a specific surface area larger than that of tin sulfide formed on the planar surface, the tin sulphide layers 210 and 220 come into contact with more electrolytic solution and the number of electrons exchanged by lithium ions can be increased. In addition, since the average free path of electrons during electron exchange is shortened, the output density can be further increased. Further, since the volume change due to charging and discharging is minimized, it is possible to provide a relatively high number of anode for a lithium ion battery.

In addition, the tin sulfide layers 210 and 220 are resistant to corrosion of the anode due to the strong corrosion resistance against the electrolytic solution. Therefore, by using the tin sulfide as the anode for the lithium ion battery, it is possible to provide a lithium ion battery having a high life and high reliability. In addition, the tin sulfide (210, 220) is an inexpensive anode material as compared with the conventional anode material, and can exhibit advantages in terms of production cost.

3A and 3B are schematic diagrams illustrating a lithium ion battery according to a first embodiment of the present invention. 3A and 3B are schematic views illustrating charging and discharging of the lithium ion battery according to the first embodiment of the present invention, respectively.

Referring to FIG. 3A, an anode 300 and a cathode 400 may be prepared. The anode 300 may be manufactured according to the anode manufacturing method for a lithium ion battery described with reference to FIGS. 1A to 1C. The cathode 400 may include a cathode active material. For example, the cathode active material may be lithium metal or lithium oxide. The lithium oxide may be, but is not limited to, lithium cobalt oxide (LiCoO ₂ ), lithium iron phosphate (LiFePO ₄ ), or lithium manganese oxide (LiMn ₂ O ₄ ) .

A separator 500 may be provided between the anode 300 and the cathode 400 to transfer lithium ions between the anode 300 and the cathode 400. [ For example, the separator 500 may be a polyolefin-based porous film such as polyethylene or polypropylene.

Between the anode 300 and the cathode 400, an electrolyte 520, which is a transfer medium of lithium ions, may be filled. The electrolytic solution 520 may be an organic solvent.

During the charging process of the lithium ion battery, the lithium ions may move from the cathode 400 to the anode 300 through the electrolyte solution 520. The following reaction formula shows the reaction between the lithium ion and the tin sulfide layer during charging.

<Reaction Scheme>

SnS _x + 2xLi ⁺ + 2xe? Sn + xLi ₂ S (x = 1 or 2)

The reaction may take place at the surface of the tin sulfide layer. The tin sulfide layer may be a tin disulfide layer having a crystalline two-dimensional hexagonal structure. The tin sulfide layer is formed of a plurality of mono-element layers, and lithium ions can be inserted or inserted between the mono-element layers, so that the capacity of the mono-layer can be increased. For example, if the tin sulphide layer is tin sulphide (SnS), the theoretical charge capacity may be 782 mAhg ^{- 1} . Also, when the tin sulfide layer is tin disulphide (SnS ₂ ), the theoretical charge capacity may be 645 mAhg ^{- 1} .

On the other hand, when the tin sulphide layer is tin disulphide, since the stability of bonding between atoms is excellent, the tin sulphide tin is superior in corrosion resistance to an electrolytic solution and can exhibit a more excellent effect in terms of stability of the anode 300 than the tin sulphide tin.

Referring to FIG. 3B, in the discharge process of the lithium ion battery, the lithium ions may move from the anode 300 to the cathode 400 in the reverse of the charging process. The reaction of the discharge process may proceed with the reverse reaction of the reaction scheme.

Since the specific surface area of the tin sulfide layer formed on the concave-convex structure of the anode 300 is increased, the surface area is wider than that of the tin sulfide layer formed on a plane, so that the amount of lithium ion emission by the above reaction formula can be increased. The number of electrons exchanged by the released lithium ions increases, so that the effect of increasing the output density of the lithium ion battery can be exhibited.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

100: collector 111, 121: concave and convex structure
111a, 121a: recesses 111b, 121b:
210, 220: a tin sulfide layer
230: tin (Sn) 240: sulfur (S)
300: anode 400: cathode (cathode)
500: separator 520: electrolyte

Claims (9)

Preparing a current collector;
Etching the one surface of the current collector to form a concavo-convex structure having a concave portion and a convex portion on one surface of the current collector; And
And laminating a tin sulfide layer on the uneven structure of the current collector. The method according to claim 1,
In the step of stacking the tin sulfide layer on the current collector,
Wherein the tin sulfide layer is deposited on the uneven structure using atomic layer deposition. 3. The method of claim 2,
Wherein the tin sulfide layer is formed by laminating a plurality of single-element layers. The method according to claim 1,
Wherein the convex portion of the current collector has a columnar structure. An anode comprising a current collector having a concavo-convex structure having a concave portion and a convex portion on a surface thereof and a tin sulfide layer stacked on the concavo-convex structure;
Cathode; And
And an electrolyte between the anode and the cathode. 6. The method of claim 5,
Wherein the convex portion of the current collector is a columnar structure. 6. The method of claim 5,
Wherein the tin sulfide layer comprises a plurality of monolayer layers. 8. The method of claim 7,
Wherein the tin sulfide layer is composed of tin sulfide or tin disulfide. 9. The method of claim 8,
Wherein the tin sulfide layer is a tin disulfide layer having a crystalline hexagonal structure.

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