KR101567884B1 - Anode structure for secondary battery and method of manufacturing the same - Google Patents

Abstract

The present invention provides a method of manufacturing a negative electrode for a secondary battery capable of providing a high capacity, high efficiency charge / discharge characteristic. According to another aspect of the present invention, there is provided a method of manufacturing a negative electrode for a secondary battery, including: forming a silicon layer on a negative electrode collector; Forming a metal capping layer on the silicon layer; And crystallizing the silicon layer according to metal induced crystallization by the metal capping layer to form a negative active material layer.

Description

[0001] The present invention relates to a negative electrode for a secondary battery, and an anode structure for a secondary battery,

TECHNICAL FIELD The present invention relates to a secondary battery, and more particularly, to a negative electrode for a secondary battery capable of providing high capacity and high efficiency charging / discharging characteristics, and a method of manufacturing the same.

Recently, the lithium secondary battery has been used as a power source for portable electronic products including mobile phones and notebook computers, as well as being used as a medium and large power source for hybrid electric vehicles (HEV) and plug-in hybrid electric vehicles (plug-in HEV) Applications are rapidly expanding. As the application field is expanded and demand is increased, the external shape and size of the battery are variously changed, and capacity, lifetime, and safety are demanded more than those required in conventional small batteries.

The lithium secondary battery uses a material capable of intercalation and deintercalation of lithium ions as a cathode and an anode and generates electricity or consumes electricity by redox reaction by insertion and desorption of lithium ions at the cathode and anode do. Graphite, which is a negative electrode active material widely used in conventional lithium secondary batteries, has a layered structure and is very useful for insertion and desorption of lithium ions. Theoretically, graphite has a capacity of 372 mAh / g, but with the recent increase in demand for high capacity lithium batteries, a new electrode capable of replacing graphite is required.

1. Korean Laid-Open Patent No. 2009-0001752 (Published on Jan. 2006, 2006) 2. Korean Patent Publication No. 2005-0078392 (Published on August 5, 2005)

Researches for the commercialization of an electrode active material that forms an electrochemical alloy with lithium ions such as silicon (Si), tin (Sn), antimony (Sb), and aluminum (Al) as a high capacity negative electrode active material have been actively conducted . However, silicon, tin, antimony, aluminum and the like have the characteristics of increasing / decreasing the volume during charging / discharging through the formation of an electrochemical alloy with lithium. The volume change due to such charging / Has the problem that the electrode cycle characteristics are deteriorated in the electrode in which the active material is introduced. Also, such a change in volume causes cracks on the surface of the electrode active material, and continuous crack formation causes undifferentiation of the surface of the electrode, thereby deteriorating cycle characteristics.

Accordingly, it is an object of the present invention to provide a negative electrode for a secondary battery and a method of manufacturing the same, which can provide high capacity and high efficiency charge / discharge characteristics. According to another aspect of the present invention, there is provided a secondary battery having a negative electrode for a secondary battery.

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

According to one aspect of the present invention, there is provided a method of manufacturing a negative electrode for a secondary battery, comprising: forming a laminate structure of a silicon layer and a crystallization inducing layer on an anode current collector; crystallizing the silicon layer according to induction crystallization by the crystallization- Thereby forming a negative electrode active material layer.

In the manufacturing method, the step of forming the negative electrode active material layer may include a step of heat-treating the silicon layer and the crystallization-inducing layer.

In the above manufacturing method, the heat treatment may be performed at a temperature that is at least half (0.5T _m ) of the melting temperature (T _m ) of the crystallization inducing layer and lower than the melting point (T _m ).

In the above manufacturing method, the negative electrode active material layer may include crystalline silicon or a combination structure of crystalline silicon and amorphous silicon.

The crystallization inducing layer may include at least one of Ni, Pd, Ti, Ag, Au, Al, Sn, Sb, Cu, Co, Mo, Tr, Ru, Rh, Cd, have.

In the above production method, the negative active material layer may have a {111} or {100} preferential crystal face on its upper surface.

In the above manufacturing method, the negative electrode active material layer may have a structure in which silicon of the silicon layer and the material of the crystallization inducing layer are mixed.

In the above manufacturing method, the negative active material layer may include a metal silicide formed by reacting silicon of the silicon layer and a material of the negative electrode collector.

In the above manufacturing method, the step of forming the laminated structure may include the step of forming the silicon layer on the negative electrode collector, and the step of forming the crystallization inducing layer on the silicon layer.

In the above manufacturing method, the step of forming the laminated structure may include the step of forming the crystallization-inducing layer on the negative electrode collector, and the step of forming the silicon layer on the crystallization-inducing layer.

A secondary battery according to another aspect of the present invention includes the above-described negative electrode for a secondary battery.

A negative electrode for a secondary battery according to still another aspect of the present invention includes a negative electrode collector and a negative electrode active material layer disposed on the negative electrode collector and including a silicon layer and a crystallization inducing layer. The silicon layer in the negative active material layer is crystallized by induction crystallization by the crystallization inducing layer.

In the negative electrode for a secondary battery, the negative electrode active material layer may further include a structure in which silicon of the silicon layer and the material of the crystallization inducing layer are mixed.

In the negative electrode for a secondary battery, the negative electrode active material layer may include the silicon layer on the negative electrode collector and the crystallization inducing layer on the silicon layer.

In the negative electrode for a secondary battery, the negative electrode active material layer may include the crystallization inducing layer on the negative electrode collector and the silicon layer on the crystallization inducing layer.

In the negative electrode for a secondary battery, the negative active material layer may include a metal silicide formed by reacting silicon of the silicon layer and a material of the negative electrode collector.

According to the method for manufacturing a negative electrode for a secondary battery according to an embodiment of the present invention, a crystalline silicon layer is crystallized by induction crystallization by a crystallization inducing layer to form a negative active material layer, thereby manufacturing a secondary battery with a high capacity economically.

The secondary battery including the negative electrode active material layer according to an embodiment of the present invention can increase the life of the secondary battery because the capacity of the secondary battery is increased and the charging capacity is hardly decreased even if the charging and discharging cycles are increased.

The effects of the present invention described above are exemplarily described, and the scope of the present invention is not limited by these effects.

1 is a schematic view showing a secondary battery according to an embodiment of the present invention.
2 is a schematic cross-sectional view illustrating an anode for a secondary battery according to an embodiment of the present invention.
3 is a schematic perspective view illustrating a negative electrode for a secondary battery according to an embodiment of the present invention.
4 is a flowchart illustrating a method of manufacturing a negative electrode for a secondary battery according to an embodiment of the present invention.
5 to 7 are cross-sectional views illustrating a method of manufacturing a negative electrode for a secondary battery according to an embodiment of the present invention.
8 is a flowchart illustrating a method of manufacturing a negative electrode for a secondary battery according to another embodiment of the present invention.
9 to 11 are cross-sectional views illustrating a method of manufacturing a negative electrode for a secondary battery according to another embodiment of the present invention.
12 is a graph illustrating a change in capacitance according to a charge cycle in a secondary battery comprising a negative electrode having a negative electrode active material layer manufactured according to embodiments of the present invention.
13 is a Raman spectrum analysis result of the anode active material layer manufactured according to the embodiments of the present invention.
14 is a scanning electron microscopic photograph and a component analysis table of the negative electrode active material layer produced according to the embodiments of the present invention.
FIG. 15 is a photograph showing the scanning electron microscope photographs of FIG. 14 classified by components.
16 is an X-ray diffraction test result of the anode active material layer produced according to an embodiment of the present invention.

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

1 is a schematic view showing a secondary battery 1 according to an embodiment of the present invention.

1, a secondary battery 1 includes a cathode 120, an anode 130, a separator 140 interposed between the cathode 120 and the anode 130, a battery container 150, and a sealing member 160 < / RTI > The secondary battery 1 may further include an electrolyte (not shown) impregnated into the cathode 120, the anode 130 and the separator 140. In addition, the cathode 120, the anode 130, and the separator 140 may be sequentially stacked and housed in the battery container 150 in a spirally wound manner. The battery container 150 can be sealed by the sealing member 160.

The secondary battery 1 may be a lithium secondary battery using lithium as a medium, and may be classified into a lithium ion battery, a lithium ion polymer battery and a lithium polymer battery depending on the type of the separator 140 and the electrolyte. The secondary battery 1 can be classified into a coin, a button, a sheet, a cylinder, a flat, a square, and the like depending on the form, and can be divided into a bulk type and a thin type according to the size. The secondary battery 1 shown in FIG. 1 is an example of a cylindrical secondary battery, and the technical idea of the present invention is not limited thereto.

The structures of the anode 130 and the cathode 120 will be described below with reference to FIGS. 2 and 3, respectively.

The separation membrane 140 may have porosity and may be composed of a single membrane or multiple membranes of two or more layers. The separation membrane 140 may include a polymer material and may include at least one of, for example, a polyethylene-based, polypropylene-based, polyvinylidene fluoride-based, and polyolefin-based polymer.

The electrolyte (not shown) impregnated in the cathode 120, the anode 130, and the separator 140 may include a non-aqueous solvent and an electrolyte salt. The nonaqueous solvent is not particularly limited as long as it is used as a nonaqueous solvent for a conventional nonaqueous electrolytic solution, and examples thereof include carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents, Solvent. The non-aqueous solvent may be used singly or in a mixture of one or more thereof. When one or more of the non-aqueous solvents are used in combination, the mixing ratio may be appropriately adjusted according to the performance of the desired battery.

The electrolyte salt is not particularly limited as long as it is used as a conventional electrolyte salt for a non-aqueous electrolyte, and may be, for example, a salt having a structural formula of A ⁺ B ^- . Here, A ⁺ may be an ion including an alkali metal cation such as Li ⁺ , Na ⁺ , K ⁺ , or a combination thereof. Also. B ^- is _{^{PF 6 -, BF 4 -,}} Cl -, Br -, I -, ClO 4 -, ASF 6 -, CH 3 CO 2 -, CF 3 SO 3 -, N (CF 3 SO 2) 2 -, C (CF ₂ SO ₂ ) ₃ ^-, and the like, or a combination thereof. For example, the electrolyte salt may be lithium-based salts, such as _{LiPF 6, LiBF 4, LiSbF 6} , LiAsF 6, LiN (SO 2 C 2 F 5) 2, Li (CF 3 SO 2) 2 N, _{LiN (SO 3 C 2 F 5} ) 2, LiC 4 F 9 SO 3, LiClO 4, LiAlO 2, LiAlCl 4, LiN (C x F 2x +1 SO 2) (C y F2 y +1 SO 2) ( where , x and y are natural numbers), LiCl, LiI, and LiB (C ₂ O ₄ ) ₂ . These electrolyte salts may be used alone or in combination of two or more.

According to a modified example of this embodiment, the separation membrane 140 may be omitted and a solid electrolyte may be interposed between the cathode 120 and the anode 130. Examples of the solid electrolyte include Li ₂ SP ₂ S ₅ , Li ₂ S-SiS ₂ , Li ₂ S-Ga ₂ S ₃ -GeS ₂ , Li ₂ S-Sb ₂ S ₃ -GeS ₂ , Li ₂ S- Based glasses or glass-ceramics such as GeS ₂ -P ₂ S ₅ , Li _{3 .25} Ge _{0 .25} P _{0 .75} S ₄ , Li _{4 .2} Ge _{0 .8} Ga _{0 .2} S ₄ , Li ₂ Ti ₃ O ₃ (LLTO), Li ₅ La ₃ Ta ₂ O ₁₂ , Li ₆ La ₂ CaTa ₂ O ₁₂ , Li ₆ La ₂ ANb ₂ O ₁₂ (A = Ca, Sr), Li ₂ Nd ₃ TeSbO ₁₂ , Li ₃ BO _{2 .5} N _{0 .5} , and Li ₉ SiAlO _8, and an oxide-based glass or glass-ceramic such as Li _{1 + x} Al _x Ge _{2 -x} (PO ₄ ) ₃ , Li _{1 + x} Ti _{2 - x} Based glasses or glass-ceramics such as Al _x (PO ₄ ) _3, Li _0.5 Ti _0.5 Zr _1.5 (PO ₄ ) _3, LiPON and the like.

2 is a schematic cross-sectional view illustrating an anode 130 for a secondary battery according to an embodiment of the present invention.

2, the anode 130 includes a cathode current collector 132 and a cathode active material layer 134 disposed on the cathode current collector 132. The positive electrode active material layer 134 includes a positive electrode active material 135 and a positive electrode binder 136 for bonding the positive electrode active material 135 thereto. In addition, the positive electrode active material layer 134 may further include a positive electrode conductor 137 selectively. Further, although not shown, the positive electrode active material layer 134 may further include an additive such as a filler or a dispersant. The anode 130 is formed by mixing the cathode active material 135, the anode binder 136, and / or the cathode conductor 137 in a solvent to prepare a cathode active material composition. The cathode active material composition is applied onto the cathode current collector 132 As shown in FIG.

The anode current collector 132 may be a thin conductive foil and may include, for example, a conductive material. The positive electrode collector 132 may include, for example, aluminum, nickel, or an alloy thereof. Alternatively, the cathode current collector 132 may be composed of a polymer containing a conductive metal. Alternatively, the positive electrode collector 132 may be formed by compressing the negative electrode active material.

The cathode active material 135 may include, for example, a cathode active material for a lithium secondary battery, and may include a material capable of reversibly intercalating / deintercalating lithium ions. The positive electrode active material 135 may include a lithium-containing transition metal oxide, a lithium-containing transition metal sulfide, and the like, for example, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , Li (Ni _a Co _b Mn _c ) _{O 2 (0 <a <1} , 0 <b <1, 0 <c <1, a + b + c = 1), LiNi 1 -y Co y O 2, LiCo 1 - y Mn y O 2, LiNi 1 _{- y} Mn _y O ₂ where 0 = Y <1, Li (Ni _a Co _b Mn _c ) O ₄ (0 <a <2, 0 <b <2, 0 <c <2, a + b + c = 2), LiMn _{2 - z} Ni _z O ₄ , LiMn _{2 - z} Co _z O ₄ (where 0 <Z <2), LiCoPO ₄ , and LiFePO ₄ .

The positive electrode binder 136 serves to adhere the particles of the positive electrode active material 135 to each other and to adhere the positive electrode active material 135 to the positive electrode collector 132. The positive electrode binder 136 may be, for example, a polymer and may include, for example, polyimide, polyamideimide, polybenzimidazole, polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, polyvinylchloride, But are not limited to, polyvinyl chloride, polyvinyl fluoride, ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene, acrylated styrene- Epoxy resin and the like.

Alternatively, the positive electrode active material 135 may use a bonding structure in which a coating layer is added to the surface of the active material layer, or a compound having an active material and a coating layer may be used. The coating layer may comprise at least one coating element compound selected from the group consisting of oxides, hydroxides of coating elements, oxyhydroxides of coating elements, oxycarbonates of coating elements, and hydroxycarbonates of coating elements. The compound constituting these coating layers may be amorphous or crystalline. In addition, the coating element contained in the coating layer is selected from the group consisting of Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, Can be used.

The positive electrode conductor 137 may be a conductive material that can further provide conductivity to the anode 130 and does not cause chemical changes to the secondary battery 1 and may be made of a conductive material such as graphite, carbon black, acetylene black, Based conductive materials such as copper, nickel, aluminum, and silver, conductive polymer materials such as polyphenylene derivatives, or a mixture thereof.

However, the structure and material of the anode 130 are illustrative, and the technical idea of the present invention is not limited thereto.

3 is a schematic perspective view showing a cathode 120 for a secondary battery according to an embodiment of the present invention.

3, the negative electrode 120 includes a negative electrode current collector 121 and a negative electrode active material layer 122 disposed on the negative electrode current collector 121.

The anode current collector 121 may include a conductive material and may include, for example, a metal, for example, copper, nickel, titanium, gold, or an alloy thereof. The anode current collector 121 can be formed by adhering, plating or vapor-depositing a foil.

The anode active material layer 122 may include, for example, a negative active material for a lithium secondary battery, and may include a material capable of reversibly intercalating / deintercalating lithium ions provided from the positive electrode 130. In one example, the anode active material layer 122 includes a silicon layer, and may optionally further include a crystallization inducing layer. Here, the silicon layer can be crystallized by induction crystallization of the crystallization-inducing layer. For example, the anode active material layer 122 may include a silicon layer on the anode current collector 121 and a crystallization inducing layer on the silicon layer. As another example, the anode active material layer 122 may include a crystallization-inducing layer on the anode current collector 121, and a silicon layer on the crystallization-inducing layer.

For example, the crystallization-inducing layer may be formed of at least one of a metal for induction crystallization, such as Ni, Pd, Ti, Ag, Au, Al, Sn, Sb, Cu, Co, Mo, Tr, Ru, Rh, One can be included. In this case, the anode active material layer 122 may be a layer formed by a metal induced crystallization (MIC) method described below. When the crystallization-inducing layer includes a metal, the crystallization-inducing layer on the silicon layer is referred to as a metal capping layer, and the crystallization-inducing layer interposed between the anode current collector 121 and the silicon layer may be referred to as a metal intervening layer.

Crystallization induction can be achieved by a general heat treatment, rapid thermal annealing, heat treatment in an electromagnetic field environment, direct injection of laser and ion beam.

The anode active material layer 122 may include crystalline silicon or a combination structure of crystalline silicon and amorphous silicon. In addition, the anode active material layer 122 may include a metal, such as aluminum, which induces metal induced crystallization of the silicon. The anode active material layer 122 may further include a metal silicide formed by reacting the metal constituting the anode current collector 121 with the silicon, for example, copper silicide.

The anode active material layer 122 may include silicon having a predetermined crystal plane, and may include silicon crystallized by, for example, a metal induced crystallization method. The crystallized silicon may first be polycrystalline silicon having a crystal plane. In this embodiment, firstly, the crystal plane means that silicon in the anode active material layer 123 is preferentially crystallized to a specific crystal plane and exists relatively more than other crystal planes, and may have a similar meaning to the orientation property. For example, the silicon may preferentially have a {111} or {100} crystal plane on the upper surface of the anode active material layer 122, and in this case, it may have a {111} or {100} preferential crystal plane. As described above, when the upper surface of the negative electrode active material layer 122 has a {111} or {100} crystal plane, it may have a {110} crystal plane on the side surface of the negative electrode active material layer 122. In the case of silicon, the lithium insertion may be preferentially given to the {110} crystal plane as compared with the {100} crystal plane or the {111} crystal plane, and thereby the volume may be expanded. That is, a volume change due to lithium insertion and desorption may occur at a side having a {110} crystal plane.

Alternatively, the case of having the {110} crystal face on the upper surface of the anode active material layer 122 is included in the technical idea of the present invention.

In this specification, {100}, {110}, and {111} denote representative planes of crystals, and {100} denotes (100), (-100), (010) (111), (111), (111), (1-11), (11-1), (-1-11) (110), (1-10), (110), (- 110), (1-11) 1-10), (101), (10-1), (-101), (-10-1), (011), (01-1) ), And the like.

In order to increase the electrical conductivity of the negative electrode active material layer 122, the negative electrode active material layer 122 may further include at least one of Group II, Group III, Group V, and Group VI impurities. For this purpose, the anode active material layer 122 may be doped with at least one of Group II, Group III, Group V, and Group VI impurities.

4 is a flowchart illustrating a method of manufacturing a cathode 120 of a secondary battery 1 according to an embodiment of the present invention. 5 to 7 are cross-sectional views illustrating a method of manufacturing the cathode 120 of the secondary battery 1 according to an embodiment of the present invention.

4 and 5, the anode current collector 121 is provided and the silicon layer 124 is formed on the anode current collector 121 (S110).

The anode current collector 121 may include a conductive material and may include, for example, a metal, for example, copper, nickel, titanium, gold, or an alloy thereof.

The silicon layer 124 may comprise amorphous silicon or may comprise polycrystalline silicon. The silicon layer 124 may be formed using a physical vapor deposition method such as sputtering or a chemical vapor deposition method such as PECVD (Plasma Enhanced Chemical Vapor Deposition) or LPCVD (Low Pressure Chemical Vapor Deposition) Chemical Vapor Deposition). The silicon layer 124 may have an appropriate thickness to maintain electrical conductivity with the anode current collector 121. For example, the silicon layer 124 may have a thickness of 300 microns or less to control the increase in resistance, but the range of this embodiment is not limited in this range.

Referring to FIGS. 4 and 6, a metal capping layer 125 is formed on the silicon layer 124 (S120).

The metal capping layer 125 may include at least one of Ni, Pd, Ti, Ag, Au, Al, Sn, Sb, Cu, Co, Mo, Tr, Ru, Rh, Cd or Pt. The metal capping layer 125 may be formed by a physical vapor deposition method such as a thermal evaporation method, a sputtering method, or a chemical vapor deposition method such as PECVD and LPCVD. For example, the metal capping layer 125 may have a thickness of about 10% or less of the thickness of the silicon layer 124 where crystallization occurs. If the thickness of the metal capping layer 125 is thicker than that, the specific gravity of silicide formation during crystallization becomes high, and the amount of silicon capable of reacting with lithium may be reduced. However, it is also possible to control the thickness of the silicon layer 124 outside such a range through changes in heat treatment conditions and the like.

Referring to FIGS. 4 and 7, the silicon layer 124 is crystallized by metal induced crystallization by the metal capping layer 125 to form a negative electrode active material layer 122 (see FIG. 3) (S130). The step of forming the negative electrode active material layer may be performed by heat-treating the silicon layer 124 and the metal capping layer 125. The heat treatment temperature may be carried out in a temperature range lower than half (0.5T _m) or more and the melting point (T _m) of the melting point (melting temperature, T _m) of the metal capping layer 125. For example, when the metal capping layer 125 is aluminum, the heat treatment temperature may range from 300 ° C to less than 600 ° C. The crystallization step may be performed in a vacuum atmosphere or an inert gas atmosphere.

8 is a flowchart showing a method of manufacturing the cathode 120 of the secondary battery 1 according to another embodiment of the present invention. 9 to 11 are cross-sectional views illustrating a method of manufacturing the cathode 120 of the secondary battery 1 according to an embodiment of the present invention.

8 and 9, an anode current collector 121 is provided, and a metal intervening layer 126 is formed on the anode current collector 121 (S210). The metal intervening layer 126 may be the same as or similar to the metal capping layer 125 described above.

Referring to FIGS. 8 and 10, a silicon layer 127 is formed on the metal intervening layer 126 (S220). The silicon layer 127 may comprise amorphous silicon or may comprise polycrystalline silicon. The silicon layer 127 may be the same or similar to the silicon layer 124 described above.

Referring to FIGS. 8 and 11, the silicon layer 127 is crystallized by metal induced crystallization by the metal intervention layer 126 to form a negative electrode active material layer 122 (see FIG. 3) (S230). The step of forming the negative electrode active material layer may be performed by heat treating the silicon layer 127. The heat treatment temperature and atmosphere may refer to the embodiments of Figs. 4 to 7 described above.

Hereinafter, results of an experimental example of a negative electrode active material layer manufactured according to an embodiment of the present invention will be discussed. The negative electrode active material layer was prepared by the method described above with reference to Figs. Specifically, an amorphous silicon layer was formed on an anode current collector made of copper, and a metal capping layer containing aluminum was formed on the amorphous silicon layer. Then, the amorphous silicon layer was heat-treated at 550 DEG C for 30 minutes to perform metal induced crystallization of the amorphous silicon layer. As a comparative example, another sample was heat-treated at 350 DEG C for 60 minutes.

FIG. 12 is a graph illustrating a change in capacitance according to a charge cycle in a secondary battery comprising a negative electrode having a negative electrode active material layer manufactured according to an embodiment of the present invention. Fig. 12 (a) shows the results for the negative electrode active material layer before metal induced crystallization, and Fig. 12 (b) shows the results for the negative electrode active material layer after metal induced crystallization.

Referring to FIGS. 12A and 12B, the initial charge capacity was about 1500 μAh / cm ² before metal induced crystallization, but the charge capacity sharply decreased as the charge / discharge cycle increased. On the other hand, after the metal induced crystallization, the initial charge capacity was reduced to about 950 μAh / cm ² before metal induced crystallization, but the charge capacity was hardly reduced even when the charge / discharge cycle was increased. The discharge was maintained at about 800 μAh / cm ² . These results indicate that the secondary battery according to the present invention has a very excellent charging capacity characteristic in accordance with the charge-discharge cycle.

13 is a Raman spectrum analysis result of the negative electrode active material layer manufactured according to an embodiment of the present invention. (b), (d), and (f) illustrate the case where a metal capping layer is included. (e), (f) and (d) show the case where the metal induced crystallization is carried out at about 350 ° C. for about 60 minutes, Is a case where metal induced crystallization is performed at about 550 DEG C for about 30 minutes.

13 (a) and 13 (b), a peak of amorphous silicon appears before the metal induced crystallization, and no peak of crystalline silicon appears.

Referring to FIGS. 13 (c) and 13 (d), after the metal induced crystallization at 350 ° C., the amorphous silicon peak appears and the crystalline silicon peak does not appear when the metal intervening layer is included, A crystalline silicon peak appears. Therefore, it can be seen that the metal induced crystallization by the metal capping layer is easier than the metal induced crystallization by the metal intervening layer.

13 (e) and FIG. 13 (f), after the metal induced crystallization at 550 ° C., the amorphous silicon peak and the crystalline silicon peak appear together when the metal intervening layer is included, A larger crystalline silicon peak appears. Therefore, it can be seen that the metal induced crystallization by the metal capping layer is easier than the metal induced crystallization by the metal intervening layer. In addition, it can be seen that the metal induced crystallization is more easily performed at 550 캜 than at 350 캜.

14 is a scanning electron microscope photograph and a component analysis table of a negative electrode active material layer manufactured according to an embodiment of the present invention. FIG. 15 is a photograph showing the scanning electron microscope photographs of FIG. 14 classified by components.

14 and 15, the anode active material layer has a structure in which aluminum constituting the metal capping layer, silicon constituting the amorphous silicon layer, and copper constituting the anode current collector are mixed. Further, the negative active material layer includes copper silicide.

16 is an X-ray diffraction test result of the anode active material layer produced according to an embodiment of the present invention. In Fig. 16, graph (d) is the peak for the specimen before the crystallization treatment, and graph (e) shows the peak for the specimen after crystallization. From the two results, it can be seen that the metal induced crystallization has silicon (111) preferential crystal face. From this, it can be seen that a negative electrode active material layer containing silicon having a {111} plane as a crystal plane first can be obtained through metal induced crystallization.

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

1: secondary battery 120: cathode
121: negative electrode current collector 122: negative electrode active material layer,
124: silicon layer 125: metal capping layer
126: metal interposition layer 127: silicon layer
130: positive electrode 132: positive electrode collector
134: positive electrode active material layer 135: positive electrode active material
136: positive electrode binder 137: positive electrode conductor
140: separator 150: battery container
160: sealing member

Claims (16)

Forming a laminated structure of a silicon layer and a crystallization inducing layer on an anode current collector; And
Crystallizing the silicon layer in accordance with induction crystallization by the crystallization inducing layer to form a negative electrode active material layer;
Lt; / RTI &gt;
The step of forming the negative electrode active material layer may include a step of heat-treating the silicon layer and the crystallization-inducing layer,
Wherein the heat treatment is performed at a temperature in a range of not less than half (0.5Tm) of the melting point (Tm) of the crystallization inducing layer and lower than the melting point (Tm)
The maximum thickness of the crystallization inducing layer is 10% of the thickness of the silicon layer,
Wherein the negative active material layer has a {111} or {100} preferential crystal face on its upper face and a {100} preferred crystal face on its side face. delete delete The method according to claim 1,
Wherein the negative electrode active material layer comprises crystalline silicon or a combination structure of crystalline silicon and amorphous silicon. The method according to claim 1,
Wherein the crystallization inducing layer comprises at least one of Ni, Pd, Ti, Ag, Au, Al, Sn, Sb, Cu, Co, Mo, Tr, Ru, Rh, Cd or Pt. . delete The method according to claim 1,
Wherein the anode active material layer has a structure in which silicon of the silicon layer and a material of the crystallization inducing layer are mixed. The method according to claim 1,
Wherein the anode active material layer comprises a metal silicide formed by reacting silicon of the silicon layer and a material of the anode current collector. The method of claim 1, wherein forming the laminated structure comprises:
Forming the silicon layer on the negative electrode collector; And
And forming the crystallization-inducing layer on the silicon layer. The method of claim 1, wherein forming the laminated structure comprises:
Forming the crystallization inducing layer on the negative electrode collector; And
And forming the silicon layer on the crystallization-inducing layer. A secondary battery comprising a negative electrode for a secondary battery formed according to the manufacturing method of any one of claims 1, 4, 5, and 7 to 10. A negative electrode for a secondary battery formed by the manufacturing method according to any one of claims 1, 4, 5, and 7 to 10,
Cathode collector; And
And a negative electrode active material layer disposed on the negative electrode collector and including a silicon layer and a crystallization inducing layer,
Wherein the silicon layer in the negative active material layer is crystallized by induction crystallization by the crystallization inducing layer. 13. The method of claim 12,
Wherein the anode active material layer further comprises a structure in which silicon of the silicon layer and a material of the crystallization inducing layer are mixed. 13. The method of claim 12,
Wherein the negative electrode active material layer comprises the silicon layer on the negative electrode collector and the crystallization-inducing layer on the silicon layer. 13. The method of claim 12,
Wherein the negative electrode active material layer includes the crystallization inducing layer on the negative electrode collector and the silicon layer on the crystallization inducing layer. 13. The method of claim 12,
Wherein the negative active material layer comprises a metal silicide formed by reacting silicon of the silicon layer and a material of the negative electrode collector.

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