KR20150042011A - Preparation method of a film comprising nanowires, the film comprising nanowires and a thin film battery conprsing the same - Google Patents

Abstract

This invention is about a preparation method of a film comprising nanowires, the film comprising nanowires and a thin film battery comprising the same. It provides a manufacturing method of inclining or spiral nanwire thin film by using sputtering method. Using this, it is possible to control the composition or crystallinity, or fine structure, while phasing the thin film with nano wires without inclining or spiral form on the plate. Thus, it can provide metallic-oxide electrode with wide contact surface and can obtain a large output and high speed charge and discharge, when using the thin film battery.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of manufacturing a thin film electrode including nanowires, a nanowire thin film electrode, and a thin film battery including the same. BACKGROUND ART [0002]

The present specification describes a method of manufacturing a thin film electrode including nanowires, a nanowire thin film electrode, and a thin film battery including the same. The method of manufacturing the thin film electrode can easily grow a thin film on which a nanowire with controlled microstructures such as an inclined shape or a spiral shape is aligned by using Glancing Angle Sputter Deposition (GASD) And a nanowire thin film electrode which has a wide contact area with controlled microstructure and is utilized for electrodes of a thin film battery and can dramatically improve high output and fast charge / discharge characteristics.

BACKGROUND ART [0002] With the advancement and refinement of the semiconductor industry in recent years, the development of microprocessing technology for the production of micro devices such as ultra-small precision mechanical parts devices using semiconductors is progressing rapidly. However, there is still a lack of research on the energy source for driving small-sized precision mechanical parts, and there is a need for a high-performance, ultra-small, And development of an ultra light cell is urgently required.

A solid-state thin film battery is proposed as a battery which can satisfy such a demand. Such a battery can be applied not only to a microelectronic and electric device but also to a power source such as a smart card, a personal mobile communication device such as a celluler phone and a PCS, or a biomedical medical electronic device to be realized in the near future. It may be applied to microelectronics, microelectromechanical system ('MEMS') and the like, which require an energy density compact cell.

A thin film battery refers to a cell in which a cathode, an electrolyte, and a cathode, which are components of a battery, are thinned. The entire solid thin film battery is a battery which can be miniaturized and has a greatly improved stability because no liquid is used in the thin film battery. All solid-state thin-film batteries have a merit that they can be used as a secondary battery with greatly improved stability. However, since the contact area between the electrode material and the electrolyte material is limited due to the use of a dense thin film, it has a fatal disadvantage that high output can not be obtained .

These disadvantages are difficult to solve simply by selecting materials and improving the composition, and it is necessary to control the microstructure to provide a contact area between the electrode and the electrolyte and a rapid movement path of ions (for example, lithium ions).

US 8,303,672 B2 (Nov. 6, 2012) Electrode for lithium secondary battery, lithium secondary battery and method for producing same

Papers: American Vacuum Society [S0734-2101 (97) 60003-2], Sculptured thin films and glancing angle deposition: Growth mechanics and application

It is an object of the present invention to provide a method of manufacturing a nanowire thin film electrode capable of controlling composition, crystallinity and microstructure of a material constituting a nanowire while growing nanowires aligned on the substrate irrespective of the surface shape of the substrate . Also, an electrode of a thin film battery including an electrode active material having a specific surface area increased by preparing a metal oxide nanowire thin film using the same is provided. Unlike conventional electrode active materials having a dense structure, the electrode of such a thin film battery provides an electrode having a relatively uniform nanowire distribution and a large specific surface area, thereby realizing high output of the thin film battery using the electrode.

According to an aspect of the present invention, there is provided a method of manufacturing a nanowire thin film electrode, comprising: preparing a substrate and a target in a chamber such that a target slope is 70 to 90 degrees; And depositing a nano-wire thin film on the substrate using a sputtering method.

The target may comprise a metal or a metal oxide.

The deposition step may be carried out by introducing a reactive gas containing oxygen into the chamber.

The deposition of the nanowire thin film in the deposition step can proceed while the substrate is rotating. The rotational speed of the substrate may be from 0 to 15 degrees per minute.

The nanowires, lithium cobalt oxide (LiCoO _2), lithium manganese oxide (LiMn ₂ O _4), lithium nickel oxide (LiNiO _2), vanadium pentoxide (V ₂ O _5), lithium iron phosphate (LiFePO _4), chromic acid lithium _{(LiCrO 2), Li [MnNiCo} ] O 2, LiVOPO 4, lithium titanate _{(Li 4 Ti 5 O 12)} , tin oxide (SnO _2), Osan upset EO byum (Nb ₂ O _5), titanium dioxide (TiO ₂₎ , Si, C, Pb, Al, Sn, and Sb.

The nanowire thin film may be in a state in which the nanowires having an inclined or spiral shape are aligned and aligned.

The substrate may include a supporting layer, a buffer layer, and a current collecting layer sequentially, wherein the nanowire thin film may be positioned on the collector layer.

The nanowire thin film may have a specific surface area of 5 to 30 m ² / g as measured by the BET method.

The introduction of the reactive gas may proceed at an inflow rate of 2 to 10 sccm based on the case where the chamber pressure is 5 mTorr.

The thickness of the nanowire thin film may be 100 to 2000 nm.

The nanowire thin film electrode according to another embodiment of the present invention includes a substrate including a support layer, a buffer layer, and a current collector layer in sequence, and a plurality of nanowires arranged on the substrate, Included are nano ship membranes.

The nanowire thin film may have a specific surface area of 5 to 30 m ² / g as measured by the BET method.

The nanowire may be made of a material selected from the group consisting of lithium cobalt oxide (LiCoO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), lithium nickel oxide (LiNiO ₂ ), vanadium pentoxide (V ₂ O ₅ ), lithium iron phosphate (LiFePO ₄ ) _{LiCrO 2), Li [MnNiCo]} O 2, LiVOPO 4, lithium titanate _{(Li 4 Ti 5 O 12)} , tin oxide (SnO _2), Osan upset EO byum (Nb ₂ O _5), titanium dioxide (TiO _2), Si, C, Pb, Al, Sn, and Sb.

In another embodiment of the present invention, the thin film battery includes a cathode, an electrolyte, and a cathode, and the anode, the cathode, or both may be the above-described nanowire thin film electrode.

The nanowire included in the anode may be at least one selected from the group consisting of lithium cobalt oxide (LiCoO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), lithium nickel oxide (LiNiO ₂ ), vanadium pentoxide (V ₂ O ₅ ) As shown in FIG.

The nanowires included in the negative electrode are made of lithium titanate (Li ₄ Ti ₅ O ₁₂ ), tin oxide (SnO ₂ ), oxyanated barium oxide (Nb ₂ O ₅ ), titanium dioxide (TiO ₂ ) And the like.

The electrolyte may be a liquid electrolyte or a solid electrolyte, and when the electrolyte is a solid electrolyte, the thin film battery may be an all solid thin film battery.

In the present specification, the term " target inclination " means " the angle between the target and the substrate " (see the symbol [theta] in Fig. 1). Specifically, the target inclination means an angle between the first plane and the second plane at a tangent line where a virtual first plane extending the substrate meets a virtual second plane extending the target.

Herein, the term " nanowire thin film " refers to a thin film in which a plurality of nanowires are arranged side by side on a substrate so that a gap is formed between a plurality of nanowires, it means.

Hereinafter, the present invention will be described in more detail.

A method of manufacturing a nanowire thin film electrode according to an embodiment of the present invention includes a preparation step of arranging a substrate and a target in a chamber so as to have a predetermined angle and a deposition step of depositing a nanowire thin film on the substrate using a sputtering method .

The angle between the substrate and the target (target slope) is preferably controlled within a range of 70 degrees to 90 degrees. Arranging the substrate and the plane so that the angle between the imaginary planes at the tangent at which the imaginary plane extending the substrate and the imaginary plane extending the target meet is 70 to 90 degrees from each other, By controlling the mass transfer when the target material reaches the substrate by forming an acute angle smaller than 90 degrees with respect to the substrate, a nanowire having an inclined angle is deposited through the deposition. When the target slope is less than 70 degrees, a dense thin film can be formed without forming a nanowire, and when the target slope exceeds 90 degrees, the deposition rate is extremely low, which makes it difficult to produce an economical thin film.

In the physical vapor deposition using a conventional sputtering method, the target and the substrate are positioned parallel to each other. In this case, the deposition is performed in such a manner that the material of the target is transferred to the substrate almost perpendicularly by the plasma. The remaining portion except the surface of the thin film called the dense thin film is filled with the material, , A thin film is formed. That is, the thin film deposited by a typical sputtering method has a feature that its surface and interior are very dense.

However, in the method of fabricating the nanowire thin film electrode, the substrate and the target are arranged to have a predetermined inclination angle to form a nanowire thin film having a wide specific surface area. In addition, there is also an advantage that a nanowire thin film can be manufactured by a simplified process such as sputtering without additional step process.

The target may be selectively applied according to the composition of the nanowire thin film to be manufactured, and a target made of a metal or a metal oxide may be applied.

The deposition step may be performed by introducing a reactive gas in an inert atmosphere or in an inert atmosphere.

As the reactive gas, oxygen gas may be applied. In this case, metal and oxygen may react with each other during the deposition process to produce a metal oxide nanowire thin film that is not a metal nanowire thin film. Even when an oxide-type nanowire thin film is to be formed, the nanowire thin film can be deposited while introducing oxygen gas as a reactive gas into the chamber in the deposition step.

When a metal oxide nanowire thin film is to be deposited using a metal target, it is necessary to introduce the oxygen gas in a deposition step with a reactive gas. Also, in the case where a metal oxide nanowire thin film is to be deposited using a metal oxide target, it is preferable to introduce the oxygen gas as a reactive gas into the chamber while introducing the deposition step. Even if a metal oxide target is used, a phenomenon in which a part of oxygen is lost under a vacuum process may occur, which may deteriorate the properties of metal oxide nanowires. For example, the crystal phase of the nanowire thin film may not be smoothly formed, or the performance of the electrode may deteriorate when the electrode is used as an electrode of a battery.

The inflow of the reactive gas may be adjusted as needed, but it is preferred that the reactive gas is introduced into the chamber at an inflow rate of 2 to 10 sccm based on a pressure of 5 mTorr in the chamber. At this time, a nanowire thin film with less defect and higher quality can be manufactured.

The deposition step may proceed with the substrate still or rotating.

When the deposition step is proceeded with the substrate being stationary, an inclined nanowire thin film can be manufactured. That is, since the nanowire thin film in which the substrate and the nanowires having a predetermined inclination are aligned in parallel is manufactured within the thin film, a nanowire thin film having a low density and a wider specific surface area can be manufactured. When this is applied to an electrode of a thin film battery, the contact area with the electrolyte can be widened as compared with the existing dense thin film.

In the case where the deposition step is performed while the substrate is rotated, a spiral nanowire thin film can be manufactured. Since the nanowires are formed in the form of helices and these helical nanowires are arranged in parallel to form a thin film, the nanowire thin films have many void spaces between the helical nanowires, and thus the specific surface area of the thin film is considerably wide. Further, the nanowire thin film also has a characteristic that the distribution of pores (void spaces between nanowires) as a whole is substantially uniform.

In order to produce the spiral nanowire thin film, the deposition step proceeds with the deposition while rotating the substrate with the target and the substrate disposed so as to form the target inclination. The substrate may be rotated at a rate of 15 degrees / minute or less, and may be 2 to 15 degrees / minute. When the rotation speed of the substrate is more than 15 degrees / minute, the nanowire thin film is not formed but a dense thin film is formed similarly to the conventional evaporation method, or a thin film composed of densely vertically arranged nanowires is formed In this case, formation of a nanowire thin film having a sufficiently large specific surface area may be difficult. In order to grow the spiral nanowire thin film, it is preferable to apply the rotating speed of the substrate at 2 to 15 degrees / minute.

The substrate may be one in which a support layer, a buffer layer, and a current collector layer are laminated in sequence, and a nanowire thin film deposited on the substrate may be included in a thin film battery and be applied as an electrode. The electrode may be an anode or a cathode, and both electrodes may be included in one thin film battery in the form of a nanowire thin film by different materials of the substrate and the nanowire thin film.

The material included in the support layer, the buffer layer, and the current collector layer may be any material as long as it is a common material used in a battery. For example, Al ₂ O ₃ , SiO ₂ as the support layer, Ti as the buffer layer, Pt But is not limited thereto.

When the electrode is utilized as an anode, the nanowire is formed of a material selected from the group consisting of lithium cobalt oxide (LiCoO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), lithium nickel oxide (LiNiO ₂ ), vanadium pentoxide (V ₂ O ₅ ) iron (LiFePO _4), chromic acid lithium _{(LiCrO 2), Li [MnNiCo} ] O 2, LiVOPO 4 , and may be one which contains any one selected from the group consisting of, wherein the nanowire is lithium cobalt oxide (LiCoO ₂ ), Lithium manganese oxide (LiMn ₂ O ₄ ), lithium nickel oxide (LiNiO ₂ ), vanadium pentoxide (V ₂ O ₅ ), and combinations thereof.

When the electrode is used as a negative electrode, the nanowire may be made of lithium titanate (Li ₄ Ti ₅ O ₁₂ ), tin oxide (SnO ₂ ), oxyanated iodine (Nb ₂ O ₅ ), titanium dioxide (TiO ₂ ) , Sn, Sb, and combinations thereof. The nanowire may be selected from the group consisting of lithium titanate (Li ₄ Ti ₅ O ₁₂ ), tin oxide (SnO ₂ ), tin oxide (Nb ₂ O ₅ ), titanium dioxide (TiO ₂ ), and combinations thereof.

The thickness of the nanowire thin film can be controlled according to the conditions of the deposition, but when the nanowire thin film is used as an electrode active material, the thickness of the nanowire thin film is preferably 200 to 2000 nm.

In addition, by using the method of manufacturing the nanowire thin film electrode, the thickness of the nanowires included in the nanowire thin film and the space between the nanowires can be controlled by changing the conditions of the deposition step. Line thickness) of 30 nm to 300 nm, and the density of nanowires per unit area is preferably ¹ × ^{10 8} / cm ² to 3 × ^{10 9} / cm ² . When the nanowire has the thickness, length, and density as described above, the specific surface area is enlarged due to the porous structure of the nanowire layer, and sufficient space exists between the nanowires, It is possible to provide a space in which the expansion can be smoothly performed even when expansion occurs. That is, when the volume expansion of the electrode material can occur according to the operating conditions of the battery, such as the electrode of the secondary battery, in order to minimize the volume expansion of the electrode itself and to improve the performance of the battery despite such volume expansion, The nanowire thin film of the present invention can form a nanowire thin film with a shape having a wide specific surface area and a proper nanowire thickness, length and density, The battery performance can be improved when the electrode is used as a material for the electrode.

The nanowire thin film has a remarkably wide specific surface area as compared with the dense thin film obtained by the conventional sputtering method. For example, the nanowire thin film has a specific surface area of 5 to 30 m ² / g as measured by the BET method . Such a wide specific surface area is wide enough to be difficult to obtain by the conventional sputtering method, and when applied to an electrode active material of a thin film battery, a contact area with the electrolyte is widened and a rapid movement route of ions can be provided. Therefore, even if an electrode including the same or thinner electrode active material is used, it is possible to obtain an output of the same or better battery as compared with the dense thin film.

The sputtering may be RF sputtering, DC magnetron sputtering, or Pulsed Laser Deposition. In the case of the RF sputtering method, the nanowire thin film described above is advantageously applicable because it has an advantage that the nanowire thin film described above can be formed without restriction on the material constituting the nanowire.

On the other hand, in comparison with the thin film deposition using the electron beam (E-beam), the sputtering method described above is more advantageous. When an electron beam is used, it is possible to form a thin film only on a specific material having a limited condition such as a metal having a low melting temperature, and it is difficult to control the porosity (or specific surface area) in the microstructure of the thin film or the thin film and thereby obtain a dense thin film or an oriented thin film And it is difficult to form a nanowire thin film having a large specific surface area as described above. However, when the sputtering method is used, nanowire thin films having various characteristics can be manufactured by the composition of the target or the reactive gas, and a nanowire thin film of controlled nanowire composition, crystallinity, microstructure, etc. can be manufactured .

The nanowire thin film having a wide specific surface area can be manufactured by a simple method using the above-mentioned method of manufacturing the nanowire thin film electrode. The nanowire thin film can be manufactured by using the nanowire material, nanowire shape, Density and the like can be adjusted. When the nanowire thin film prepared by the above method is used as an electrode active material, it is possible to solve the problem of a low output power which has been pointed out as a problem of a thin film battery and can be applied not only to a liquid electrolyte but also to a thin film battery using a solid electrolyte, Thereby enabling high output of the battery.

Particularly, when the nanowire thin film is applied to the entire solid thin film battery, the application range of which is limited due to low output, it is possible to realize a full solid thin film battery having a high output. Microstructural properties, which are less dense than conventional deposition methods and have a high porosity, provide a fast moving path of reaction area and ions, making it possible to fabricate a high-output electrochemical device capable of high-speed charge and discharge. By using this, the entire solid thin film battery known to have excellent stability can be applied in a high output environment, and thus the application range of the thin film battery can be drastically expanded.

A nanowire thin film electrode according to another embodiment of the present invention includes a substrate including a supporting layer, a buffer layer, and a current collecting layer in sequence, and a nano-vessel disposed on the substrate, Film. The nanowire may be an inclined or spiral nanowire. A detailed description of the nanowire thin film electrode is omitted because it overlaps with the description of the method of manufacturing the nanowire thin film electrode described above.

A thin film electrode according to another embodiment of the present invention includes a cathode, an electrolyte, and a cathode, and the anode, the cathode, or both are the above-described nanowire thin film electrodes. The electrolyte may be a liquid electrolyte or a solid electrolyte, and the contact area between the electrode active material and the electrolyte may be increased, thereby providing a highly efficient thin film electrode.

The nanowire included in the positive electrode may be selected from the group consisting of lithium cobalt oxide (LiCoO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), lithium nickel oxide (LiNiO ₂ ), vanadium pentoxide (V ₂ O ₅ ) (LiCoO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), lithium nickel oxide (LiNiO ₂ ), vanadium pentoxide (V ₂ O ₅ ), and combinations thereof. Or a combination thereof.

The nanowires included in the negative electrode are made of lithium titanate (Li ₄ Ti ₅ O ₁₂ ), tin oxide (SnO ₂ ), oxyanated barium oxide (Nb ₂ O ₅ ), titanium dioxide (TiO ₂ ) (Li ₄ Ti ₅ O ₁₂ ), tin oxide (SnO ₂ ), niobium oxide (Nb ₂ O ₅ ), titanium dioxide (TiO ₂ ), and combinations thereof. And combinations thereof.

The thin film battery may be an all-solid-state thin-film battery, and solves the low-output problem that has been a hindrance to the utilization of the entire solid-state thin-film battery, thereby providing a high output thin-film battery.

The nanowire thin film electrode manufacturing method of the present invention provides a method of manufacturing a nanowire thin film electrode capable of controlling composition, crystallinity and microstructure. The nanowire thin film electrode has a wide specific surface area and can control the composition, shape, and crystallinity, so that various modified nanowire thin films can be manufactured. Also, Lt; / RTI > When this is applied to a thin film battery, the contact area between the electrode active material and the electrolyte can be drastically increased, and the interface between the aggregated nanowires serves to provide a fast path for ions (for example, lithium ions) The output of the solid-state thin film battery can be improved, and the application range of the all-solid-state thin film battery can be greatly expanded by operating in a high output environment.

FIG. 1 is a schematic view showing a target position and the inside of a vacuum chamber for depositing a nanowire thin film by the GASD method. FIG.
2 is a schematic diagram of a helical nanowire thin film electrode deposited on a substrate by the GASD method.
FIG. 3 is a graph showing the microstructure of the helical structure of the nanowire thin film obtained by the GASD method in Example 1. The cross section of the nanowire thin film was observed by a scanning electron microscope.
4 is a schematic diagram of an oblique nanowire thin film electrode deposited on a substrate by the GASD method.
FIG. 5 is a microscopic observation of the microstructure of an oblique-structured nanowire thin film obtained by the GASD method according to Example 2. The cross-section of the nanowire thin film was observed with a scanning electron microscope.
FIG. 6 is a photograph of the microstructure of a dense structure thin film deposited by sputtering according to Comparative Example 1, and the cross-section of the dense thin film observed with a scanning electron microscope.
7 is a microscopic observation of the microstructure of the dense structure deposited by sputtering according to Comparative Example 2. The cross-section of the dense thin film was observed with a scanning electron microscope.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Like parts are designated with like reference numerals throughout the specification.

Example  1: spiral Narrow  A thin-film cathode active material-containing electrode Former solidarity  Preparation and characterization of thin film battery

In order to fabricate a thin film having a nanowire structure aligned on a substrate, an example in which LiCoO ₂ , an active material of a secondary battery, is selected will be described. This thin film can be utilized as a positive electrode of a secondary battery.

Platinum (Pt, thickness: 100 nm) serving as a current collector layer was densely formed on an alumina (Al ₂ O ₃ ) substrate, and LiCoO ₂ (LCO) was rotated by Glancing Angle Sputter Deposition (GASD) (rotation). Each process will be described in detail as follows.

(One) House floor  Deposition and cleaning steps

Acetone to aluminum oxide (Al ₂ O ₃₎ substrate (acetone), 0.1 mol / ℓ of HCl, ethanol (ethanol), after 5 minutes sonication (sonication) each with deionized water (DI water), UV cleaning (UV cleaner for 5 minutes.

After the cleaned substrate was placed in a vacuum chamber, the initial vacuum level was maintained at 5 × 10 ^-6 Torr or lower. Then, in order to remove the oxide layer and prevent impurities from entering the Ti target surface, a gas pressure of 5 mTorr, RF power 100 W for 10 minutes. In a pure argon atmosphere, a Ti buffer layer was deposited by sputtering at an RF power of 100 W for 1 hour while keeping the gas pressure at 5 mTorr.

Thereafter, a Pt collector layer was deposited by sputtering for 15 minutes while maintaining the gas pressure at 5 mTorr and the DC power at 40 W in a pure argon atmosphere.

In order to clean the surface of the LCO target, which constitutes the cathode active material, the initial vacuum degree of the sputtering was maintained at 5 × 10 ^-6 torr or lower, and the cleaning was performed under a gas pressure of 5 mTorr and RF power of 150 W under a pure argon atmosphere.

(2) Narrow  Structure Thin-film electrode deposition step

After the temperature inside the chamber was fixed to room temperature, LiCoO ₂ (LCO) was sputtered at an RF power of 150 W on a substrate including a current collector layer obtained through the process of (1). At this time, the angle of the target to be sputtered (target slope) was 70 to 90 ° with respect to the substrate to perform deposition. At this time, instead of fixing the substrate, the substrate was rotated and rotated at a rotation speed of 30 DEG / 2 min. The pressure in the chamber was maintained at 1 mTorr while flowing a small amount of oxygen. In this deposition process, a nanowire thin film with a spiral structure was formed.

The deposited nanowire thin film was made into a crystalline LiCoO ₂ (LCO) nanowire thin film by performing heat treatment for 1 hour while maintaining 700 ° C. in an O ₂ atmosphere, and was then applied to an electrode of a thin film battery .

(3) Solid electrolyte deposition step

After fixing the temperature to room temperature, LiPON was sputtered with RF power of 200 W on the substrate (electrode) on which the electrode active material thin film was formed, as described in (2) above. At this time, the target used was Li ₃ PO _4, and the pressure in the chamber was kept at 5 mTorr and sputtering was performed while flowing a large amount of reactive gas, N ₂ .

(4) Li metal Deposition step

Li metal was deposited on the electrode on which the solid electrolyte was deposited up to step (3) by using a thermal evaporator.

(5) cell test  step

All of the solid-state batteries having undergone the above-mentioned processes (1) to (4) were subjected to a cell test at a low C-rate (1 C-rate) and a high C-rate (5 C-rate) using a constant current method. The results are shown in Table 1 below, and their characteristics were compared with Comparative Example 1 described below.

Comparative Example  One

Titanium (Ti, thickness 100 nm), Ti (platinum) (100 nm thick) serving as a current collecting layer were densely formed on the alumina (Al ₂ O ₃ ) substrate and LiCoO ₂ (LCO) And was deposited by a normal sputtering method. Specifically, the deposition and cleaning of the current collector layer of (1) in Example 1 were carried out in the same manner, but in the process of (2), LCO deposition was performed in the same manner as in the ordinary sputtering without forming a target slope. In this process, a dense thin film was formed as shown in Fig.

Thereafter, cell tests were carried out in the same manner as in Example 1 (3) and (4), and the same cell test as in (5) was carried out.

Electrode active material
Fine shape of thin film Low C-rate (1 C-rate) 100 cycle capacity retention High C-rate (5 C-rate) 100 cycle capacity retention Comparative Example 1 Compact structure 88% 81% (30 cycles) Example 1 Aligned structure of spiral lines 96% 94%

Referring to Table 1, it was confirmed that the thin film battery of Example 1 including the same electrode active material of 450 nm had a significantly improved capacity retention as compared with the thin film battery of Comparative Example 1. [ This is because the electrode active material structure in which the spiral nanowires of Example 1 are aligned in comparison with the structure of the cathode active material thin film of the precise Comparative Example 1 shows a high capacity characteristic of the battery of Example 1 which is the entire solid thin film battery Is considered to be implemented.

Example  2: Inclined Narrow  A thin-film cathode active material-containing electrode Former solidarity  Preparation and characterization of thin film battery

In order to fabricate a thin film having a nanowire structure aligned on a substrate, an example in which V ₂ O ₅ , which is a cathode active material of a secondary battery, is selected will be described. This thin film can be utilized as a positive electrode of a secondary battery.

Titanium (Ti, thickness: 100 nm), which is a buffer layer, was densely deposited on a silicon (SiO ₂ ) substrate, and platinum (Pt, thickness: 100 nm) as a current collector layer was densely deposited. The cathode active material, V ₂ O _5, was deposited by GASD method to have a graded nanowire structure. Each process will be described in detail as follows.

(One) House floor  Deposition and cleaning steps

The silicon (SiO ₂ ) substrate was sonicated for 5 minutes each with acetone, 0.1 mol / l HCl, ethanol, and DI water, and then immersed in a UV cleaner It was cleaned for 5 minutes.

After the cleaned substrate was placed in a vacuum chamber, the initial vacuum level was maintained at 5 × 10 ^-6 Torr or lower. Then, in order to remove the oxide layer and prevent impurities from entering the Ti target surface, a gas pressure of 5 mTorr, RF power 100 W for 10 minutes. In a pure argon atmosphere, a Ti buffer layer was deposited by sputtering at an RF power of 100 W for 1 hour while keeping the gas pressure at 5 mTorr.

Thereafter, a Pt collector layer was deposited by sputtering for 15 minutes while maintaining the gas pressure at 5 mTorr and the DC power at 40 W in a pure argon atmosphere.

In order to clean the surface of the V target, which is a constituent of the cathode active material, the initial vacuum degree of the sputtering was maintained at 5 × 10 ^-6 torr or less, and the cleaning was performed under a condition of a gas pressure of 5 mTorr and a DC power of 200 W under a pure argon atmosphere.

(2) Narrow  Structure Thin-film electrode deposition step

After the temperature inside the chamber was fixed to room temperature, V was sputtered at a DC power of 200 W on a substrate including a current collecting layer after the process of (1). At this time, the angle of the target to be sputtered (target slope) was 70 to 90 ^{° C.} and the deposition was performed. At this time, after the substrate was fixed, a slight amount of oxygen was flowed while maintaining the pressure in the chamber at 2.5 mTorr, and the reaction was performed with V ₂ O ₅ . A V ₂ O ₅ nanowire thin film with an inclined structure was formed on the current collector layer. In this process, a nanowire thin film having a shape similar to that shown in FIG. 5 having an inclined structure was formed.

(3) Solid electrolyte deposition step

After fixing the temperature to room temperature, LiPON was sputtered with RF power of 200 W on the substrate (electrode) on which the electrode active material thin film was formed, as described in (2) above. At this time, the target used was Li ₃ PO _4, and the pressure in the chamber was kept at 5 mTorr and sputtering was performed while flowing a large amount of reactive gas, N ₂ .

(4) Li metal Deposition step

Li metal was deposited on the electrode on which the solid electrolyte was deposited up to step (3) by using a thermal evaporator.

(5) cell test  step

All of the solid-state batteries having undergone the above-mentioned processes (1) to (4) were subjected to a cell test at a low C-rate (1 C-rate) and a high C-rate (5 C-rate) using a constant current method. The results are shown in Table 2 below, and their characteristics were compared with Comparative Example 2 described below.

Comparative Example  2

Titanium (Ti, thickness: 100 nm), which is a buffer layer, was densely deposited on a silicon (SiO ₂ ) substrate, and platinum (Pt, thickness: 100 nm) as a current collector layer was densely deposited. Here, V ₂ O ₅ , which is a cathode active material, was deposited by a conventional sputtering method. As the specific volume, the deposition and cleaning of the current collector layer of (1) in Example 2 were carried out in the same manner, but in the process of (2), V ₂ O _{5 was} deposited in the same manner as in the ordinary sputtering method without forming a target slope Respectively. In this process, a dense thin film was formed as shown in FIG.

Thereafter, cell tests were carried out in the same manner as in Example 2 (3) and (4), and the same cell test as in (5) was carried out.

Electrode active material
Fine shape of thin film Low C-rate (1 C-rate) 100 cycle capacity retention High C-rate (5 C-rate) 100 cycle capacity retention Comparative Example 2 Compact structure 77% (34 cycles) X (not measurable) Example 2 Arranged structures of warped nanowires 77% 63%

Referring to Table 2, it was confirmed that the thin film battery of Example 2 including the same 200 nm electrode active material had a significantly improved capacity retention as compared with the thin film battery of Comparative Example 2. [ This is because the capacity characteristic of the battery of Example 2 is realized by the specific surface area of the wide electrode active material in the electrode active material structure in which the warp type nanowires of Example 2 are aligned as compared with the structure of the cathode active material thin film of the precise Comparative Example 2 I think.

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, Of the right.

1. Substrate
2. Buffer layer
3. Whole layer
4. Nanowire thin film

Claims (16)

Preparing a substrate and a target in a chamber so that a target inclination is 70 to 90 degrees; And
And depositing a nano-wire thin film on the substrate using a sputtering method. The method according to claim 1,
Wherein the target comprises a metal or a metal oxide,
Wherein the deposition step is performed by introducing a reactive gas containing oxygen into the chamber. The method according to claim 1,
Wherein the deposition of the nanowire thin film in the deposition step proceeds while the substrate rotates and the rotation rate of the substrate is 0 to 15 degrees / minute per minute. The method according to claim 1,
The nanowires, lithium cobalt oxide (LiCoO _2), lithium manganese oxide (LiMn ₂ O _4), lithium nickel oxide (LiNiO _2), vanadium pentoxide (V ₂ O _5), lithium iron phosphate (LiFePO _4), chromic acid lithium _{(LiCrO 2), Li [MnNiCo} ] O 2, LiVOPO 4, lithium titanate _{(Li 4 Ti 5 O 12)} , tin oxide (SnO _2), Osan upset EO byum (Nb ₂ O _5), titanium dioxide (TiO ₂₎ , Si, C, Pb, Al, Sn, and Sb. The method according to claim 1,
Wherein the nanowire thin film is in a state in which an oblique or helical nanowire is aligned and aligned in parallel. The method according to claim 1,
Wherein the substrate comprises a support layer, a buffer layer, and a current collecting layer sequentially, and the nanowire thin film is positioned on the collector layer. The method according to claim 1,
Wherein the nanowire thin film has a specific surface area of 5 to 30 m ² / g as measured by a BET method. The method according to claim 1,
Wherein the target slope is an angle between the first plane and the second plane at a tangent line where a virtual first plane extending the substrate meets a virtual second plane extending the target. The method according to claim 1,
Wherein the nanowire thin film has a thickness of 100 to 2000 nm. 1. A nanowire thin film electrode comprising: a substrate comprising a support layer, a buffer layer and a current collecting layer; and a nano-ship membrane disposed on the substrate and arranged in an aligned arrangement of tapered or helical nanowires. 11. The method of claim 10,
Wherein the nanowire thin film has a specific surface area of 5 to 30 m ² / g as measured by the BET method. 11. The method of claim 10,
The nanowire may be made of a material selected from the group consisting of lithium cobalt oxide (LiCoO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), lithium nickel oxide (LiNiO ₂ ), vanadium pentoxide (V ₂ O ₅ ), lithium iron phosphate (LiFePO ₄ ) _{LiCrO 2), Li [MnNiCo]} O 2, LiVOPO 4, lithium titanate _{(Li 4 Ti 5 O 12)} , tin oxide (SnO _2), Osan upset EO byum (Nb ₂ O _5), titanium dioxide (TiO _2), Si, C, Pb, Al, Sn, and Sb. An anode, an electrolyte, and a cathode,
Wherein the anode, the cathode, or both are nanowire thin film electrodes according to claim 10. 14. The method of claim 13,
Wherein the electrolyte is a liquid electrolyte or a solid electrolyte. 14. The method of claim 13,
The nanowires included in the positive electrode include lithium cobalt oxide (LiCoO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), lithium nickel oxide (LiNiO ₂ ), vanadium pentoxide (V ₂ O ₅ ), lithium iron phosphate (LiFePO ₄ ), Lithium chromate (LiCrO ₂ ), Li [MnNiCo] O ₂ , LiVOPO _4, and combinations thereof. 14. The method of claim 13,
The nanowires included in the negative electrode include lithium titanate (Li ₄ Ti ₅ O ₁₂ ), tin oxide (SnO ₂ ), niobium oxide (Nb ₂ O ₅ ), titanium dioxide (TiO ₂ ), Si, C, Pb , Al, Sn, Sb, and combinations thereof.

Images