KR20160087121A - Multi layered Anode Comprising Si-Based Material and Secondary Battery Comprising the Same - Google Patents

Abstract

The present invention relates to a negative electrode for a secondary battery and a secondary battery comprising the same. The negative electrode for a secondary battery is characterized in that a negative electrode mixture layer comprising a negative electrode active material, a binder, and a conducting material is formed on a negative electrode current collector, wherein the negative electrode mixture layer comprises: a first coating layer which is in contact with the negative electrode current collector and includes a conducting material and a binder; a second coating layer including a binder, a conducting material, and a negative electrode active material which comprises a carbonaceous material, or the carbonaceous material and a silicon-based material; and a third coating layer including a binder, a conducting material, and a negative electrode active material which comprises the carbonaceous material and silicon-based material and has a relatively high content ratio of the silicon-based material compared to the second coating layer, and having a relatively thin average thickness compared to an average thickness of the second coating layer. According to the present invention, a secondary battery comprising the negative electrode shows excellent safety and capacity properties.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a multi-layered cathode including a silicon-based material and a secondary battery including the same,

[0001] The present invention relates to a negative electrode having a multilayer structure including a silicon-based material and a secondary battery comprising the same. More particularly, the present invention relates to a negative electrode having a negative electrode active material layer having a first coating layer, a second coating layer, And a secondary battery including the negative electrode.

As technology development and demand for mobile devices are increasing, the demand for secondary batteries as energy sources is rapidly increasing. Among such secondary batteries, lithium secondary batteries having high energy density and voltage, long cycle life and low self- It has been commercialized and widely used.

Such a lithium secondary battery includes a lithium-containing manganese oxide such as lithium-containing cobalt oxide (LiCoO ₂ ) having a layered crystal structure, LiMnO _{2 having a} layered crystal structure, LiMn ₂ O _{4 having a} spinel crystal structure, and lithium- LiNiO ₂₎ and commonly used. In addition, a carbon-based material is mainly used as an anode active material, and recently, a silicon-based material having an effective capacity ten times or more higher than that of a carbon-based material is considered to be mixed with the demand for a high capacity secondary battery.

However, lithium secondary batteries have various problems, some of which are related to cathode manufacture and operating characteristics.

For example, in a carbon-based negative active material, a solid electrolyte interface (SEI) layer is formed on the surface of the negative electrode active material during the initial charging / discharging process (activation process) , There is a problem that the capacity of the battery decreases due to the depletion of the electrolyte during the collapse and regeneration process of the SEI layer during the continuous charge / discharge process.

Further, although the silicon-based material exhibits a high capacity of 3000 mA / g or more, the SEI layer is lost due to the volume expansion rate of 300% or more as the cycle progresses, leading to an increase in resistance and an increase in side reaction in the electrolyte. The problems due to the formation of the layer can be intensified.

In order to solve this problem, various attempts have been made to form SEI layers with stronger bonds or to form an oxide layer on the surface of the anode active material. However, there have been various attempts to reduce the electric conductivity by the oxide layer, It does not show enough characteristics to be applied to commercialization.

In addition, an additive may be used for the electrolytic solution. However, the electrolyte additive conventionally used has a main function to prevent side products generated during charging and discharging.

Therefore, there is a great need for a technology that can fundamentally solve these problems.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

The inventors of the present application have conducted intensive research and various experiments, and as described later, when a negative electrode having a multi-layer structure including a silicon-based material is used, the electrode adhesiveness is improved and a problem due to the volume expansion of the silicon- Can be solved, and a secondary battery having excellent electrode manufacturing processability and high capacity can be produced, and thus the present invention has been accomplished.

Accordingly, the present invention provides a negative electrode active material composition comprising a negative electrode active material layer including a negative electrode active material, a binder and a conductive material formed on a negative electrode current collector, the negative electrode material mixture layer being in contact with the negative electrode current collector, Coating layer; A second coating layer comprising a carbon-based material or a negative electrode active material containing a carbon-based material and a silicon-based material, a conductive material, and a binder; And an anode active material including a carbon-based material and a silicon-based material and having a relatively higher content of silicon-based material than the second coating layer, a conductive material and a binder, and having an average thickness relatively thinner than an average thickness of the second coating layer 3 coating layer on the surface of the negative electrode.

When the carbon-based material and the silicon-based material are used as the anode active material in order to improve the capacity of the secondary battery, as the cycle progresses due to a large electrode expansion compared to the carbon-based material of the silicon-based material, The problems due to the formation of the SEI layer can be further exacerbated.

Accordingly, the present invention solves the problem of volume expansion that may occur when a silicon-based material is used by using a negative electrode including a negative electrode mixture layer of the first coating layer, the second coating layer and the third coating layer structure to secure safety And the secondary battery having improved capacity characteristics can be manufactured.

Specifically, the first coating layer of the present invention includes a conductive material and a binder and has an effect similar to that of a primer coating layer because of its contact with the anode current collector. As a result, not only the adhesion between the anode mixture layer and the anode current collector, Can be improved.

The content of the conductive material in this first coating layer is 60 to 90 wt% based on the total weight of the first coating layer, and the content of the binder may be 10 to 40 wt% based on the total weight of the first coating layer , In detail, the content of the conductive material may be 70 wt% to 85 wt%, and the content of the binder may be 15 wt% to 30 wt%.

When the content of the conductive material is more than 90% by weight and the content of the binder is less than 10% by weight, the effect of improving the electrode adhesion between the negative electrode mixture layer and the negative electrode collector can not be expected, and the content of the conductive material is less than 60% When the content of the binder is more than 40% by weight, it is not preferable to maximize the electric conductivity and to maintain the effect of coating the first coating layer.

The binder of the first coating layer is not limited as long as it is generally used in the art. Examples of the binder include CMC (carboxymethylcellulose), PVA (polyvinyl alcohol), PVDF (polyvinylidene fluoride), PVP (polyvinylpyrrolidone) ), And SBR (Styrene Butadiene Rubber).

When the carbon-based material and the silicon-based material are mixed and used, the content of the silicon-based material is preferably such that the amount of the silicon-based material contained in the negative electrode of the second coating layer More specifically not more than 1% by weight, more specifically not less than 0.1% by weight and not more than 1% by weight, based on the total weight of the active material, ≪ / RTI >

Since the silicon-based material has a larger volume expansion rate than the carbon-based material due to the progress of the cycle, the negative electrode mixture layer containing the silicon-based material generates stress due to expansion of the particles. As the content of the silicon-based material increases, the stress is increased. However, when the silicon-based material is divided into two anode mixture layers, rather than including all of the silicon-based materials in one anode mixture layer, .

Accordingly, in the present invention, the silicon-based material may be divided into a second coating layer and a third coating layer in detail.

The third coating layer may include a carbon-based material and a silicon-based material as the negative electrode active material, and the content ratio of the silicon-based material may be relatively higher in the entire negative electrode active material than in the second coating layer. As one example, the content of the silicon-based material may be 5 wt% or more to 20 wt% or less, and more specifically 10 wt% or more to 15 wt% or less based on the total weight of the negative electrode active material of the third coating layer.

The content of the silicon-based material present in each of the second coating layer and the third coating layer is an optimum value set in accordance with experiments in consideration of the stress due to the expansion of the silicon-based material during charging and discharging, The increase of the energy density is difficult and the desired capacity improvement effect can not be exhibited. If the energy density is excessively large, the volume expansion of the negative electrode may be increased, which is not preferable.

As described above, the content ratio of the silicon-based material in the negative electrode active material is relatively high and the content ratio of the carbon-based material in the third coating layer is relatively low as compared with the second coating layer, and the average thickness of the third coating layer is May be from 3% to 40%, and in particular from 5% to 30%, based on the average thickness.

If the average thickness of the third coating layer exceeds 40% of the thickness of the second coating layer, the thickness of the entire negative electrode material mixture layer becomes excessively thick, so that the electrolyte impregnation property may deteriorate. When the average thickness of the third coating layer is less than 3% Which is undesirable.

In the case of the second coating layer having a relatively high content ratio of the carbon-based material, it occupies most of the negative electrode mixture layer. For example, the average thickness may be 50% to 95% of the total average thickness of the negative electrode material mixture layer, Can be from 60% to 90%.

When the average thickness of the second coating layer exceeds 95% of the total average thickness of the negative electrode mixture layer, the average thickness of the first coating layer and the third coating layer becomes relatively small, so that the adhesive strength of the negative electrode material mixture layer is decreased or the capacity of the battery is difficult If it is less than 50%, the amount of the carbon-based material in the negative electrode mixture layer becomes too small, which is not preferable.

The average thickness of the first coating layer can be freely determined according to the thickness of the second coating layer and the third coating layer. However, considering the nature of the primer coating layer, for example, the average thickness of the first coating layer may be relatively thin have.

The binder of the second coating layer and the third coating layer may include SBR and / or CMC. In the case of the silicon-based material, when used in combination with an aqueous binder such as SBR, the volume expansion due to the progress of the cycle can be suppressed, and CMC is preferable because the coating process can be smoothly performed by increasing the viscosity of the electrode mixture.

Since the content of the silicon-based material is relatively higher in the third coating layer than in the second coating layer, the content ratio of the binder may be relatively higher than that of the second coating layer in order to suppress the expansion of the silicon-based material.

As one example, the content of the binder in the third coating layer may be 3% by weight or more and 20% by weight or less, and more specifically 5% by weight or more and 15% by weight or less based on the total weight of the third coating layer.

When the content of the binder is less than 3% by weight, the volume expansion of the silicon-based active material can not be suppressed with the progress of the cycle. When the content of the binder is more than 15% by weight, the amount of the negative electrode active material is relatively small, I do not.

In the present invention, the carbon-based material is not limited as long as it is used in the art, and examples thereof include graphite, artificial graphite, MCMB (MesoCarbon MicroBead), carbon fiber and carbon black acetylene black, And may be graphite in detail.

The silicon-based material may include, for example, silicon, an alloy of silicon, SiB ₄ , SiB ₆ , Mg ₂ Si, Ni ₂ Si, TiSi ₂ , MoSi ₂ , CoSi ₂ , NiSi ₂ , CaSi ₂ , CrSi ₂ , Cu ₅ Si, FeSi ₂ , MnSi ₂ , NbSi ₂ , TaSi ₂ , VSi ₂ , WSi ₂ , ZnSi ₂ , SiC, Si ₃ N ₄ , Si ₂ N ₂ O, SiO _v (0.5 ≦ _v ≦ 1.2) And more specifically SiO _v (0.5? _V ? 1.2), and more particularly SiO.

Such silicon oxide (SiO) may be a material in which silicon dioxide (SiO ₂ ) and amorphous silicon are mixed at a mixing ratio of 1: 1 based on the weight ratio.

In the present invention, the negative electrode material mixture layer may be formed in the order of the first coating layer, the second coating layer and the third coating layer on the anode current collector, or may be formed in the order of the first coating layer, the third coating layer, .

The method of forming the coating layer in the present invention is not particularly limited as long as it is used in the art. For example, the first coating layer including the negative electrode current collector and the binder is dried, And the second coating layer and the third coating layer may be sequentially formed on the first coating layer in this order or the third coating layer and the second coating layer may be formed in this order.

As another example, the electrode mixture may be formed on the current collector by a method such as spray coating.

The present invention provides a secondary battery including the negative electrode for a secondary battery, wherein the secondary battery is a lithium secondary battery.

Hereinafter, the configuration of such a lithium secondary battery will be described.

The lithium secondary battery includes a positive electrode prepared by applying a mixture of a positive electrode active material, a conductive material and a binder on a positive electrode collector, followed by drying and pressing, and a negative electrode prepared using the same method. In this case, A filler is further added to the mixture.

The cathode current collector generally has a thickness of 3 to 500 mu m. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. Examples of the positive electrode current collector include stainless steel, aluminum, nickel, titanium, sintered carbon, aluminum or stainless steel A surface treated with carbon, nickel, titanium, silver or the like may be used. The current collector may have fine irregularities on the surface thereof to increase the adhesive force of the cathode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

Lithium manganese oxides such as lithium nickel oxide (LiNiO ₂ ) represented by the formula Li _{1 + x} Mn _{2 -x} O ₄ (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ and LiMnO ₂ as the positive electrode active material; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; A Ni-site type lithium nickel oxide expressed by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3); Formula _{LiMn 2-x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 ~ 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); A lithium manganese composite oxide having a spinel structure such as LiNi _x Mn _2-x O ₄ (x = 0.01 to 0.6); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ , and the like.

The conductive material is usually added in an amount of 1 to 50% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is a component that assists in bonding of the active material and the conductive material and bonding to the current collector, and is usually added in an amount of 1 to 50 wt% based on the total weight of the mixture containing the cathode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, and various copolymers.

The filler is optionally used as a component for suppressing expansion of the anode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. Examples of the filler include olefin-based polymerizers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The negative electrode current collector is generally made to have a thickness of 3 to 500 mu m. Such an anode current collector is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, and examples of the anode current collector include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, a surface of copper or stainless steel A surface treated with carbon, nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. In addition, like the positive electrode collector, fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.

Such a lithium secondary battery may have a structure in which a lithium salt-containing electrolyte is impregnated in an electrode assembly having a separator interposed between an anode and a cathode.

The separation membrane is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m, and the thickness is generally 5 to 300 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

The lithium salt-containing electrolyte is composed of a nonaqueous solvent and a lithium salt, the lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO _4, LiBF _4, LiB ₁₀ Cl _{10, LiPF 6, LiCF 3 SO} 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, 4 Lithium phenylborate, imide and the like can be used.

Examples of the non-aqueous solvent include, but are not limited to, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC) Ethyl methyl carbonate (EMC) methyl propionate (MP) and ethyl propionate (EP).

For the purpose of improving the charge / discharge characteristics and the flame retardancy, the electrolytic solution is preferably mixed with an organic solvent such as pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, Benzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, . In some cases, halogen-containing solvents such as carbon tetrachloride, ethylene trifluoride and the like may be further added to impart nonflammability. In order to improve the high-temperature storage characteristics, a carbon dioxide gas may be further added, and PRS (propene sultone) And the like.

In a preferred _{embodiment, LiPF 6, LiClO 4, LiBF} 4, LiN (SO 2 CF 3) may be added to the lithium salt of _2, and so on, in the highly dielectric solvent, to prepare a lithium salt-containing non-aqueous electrolyte by.

The battery pack including at least one lithium secondary battery may be used as a power source for devices requiring high temperature stability, long cycle characteristics, and high rate characteristics.

Examples of the device include a large-sized device such as an electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV) In addition, it may be a small device such as, but not limited to, a mobile phone, a notebook computer, a netbook, a tablet PC, a PDA, a digital camera, a portable navigator,

As described above, the secondary battery according to the present invention uses a negative electrode having a multi-layered negative electrode mixture layer including a silicon-based material, thereby increasing the capacity of the electrode while improving the electrode adhesion, It is possible to secure safety and excellent electrode manufacturing processability.

≪ Example 1 >

DENKA BLACK as a conductive material and PVdF as a binder were mixed in an amount of 8: 2 by weight, and then the mixture was applied onto an anode current collector to form a first coating layer.

(99: 1 by weight) of natural graphite and SiO 2 as a negative electrode active material, SBR and CMC as a conductive black as binders were mixed in distilled water at a weight ratio of 97: 0.5: 2.5 and mixed to prepare a negative electrode mixture. Layer.

Natural graphite and SiO 2 (95: 5 by weight) were used as the negative electrode active material, and SBR and CMC as the conductive materials were mixed in distilled water at a weight ratio of 93.5: 0.5: 6, and mixed to prepare a negative electrode mixture. Coated on a layer, rolled and dried to prepare a negative electrode.

The average thickness ratio of the first coating layer, the second coating layer and the third coating layer was 0.5: 6.5: 3.

≪ Example 2 >

A negative electrode was prepared in the same manner as in Example 1, except that the conductive material and the binder were mixed in a weight ratio of 6: 4 in the first coating layer.

≪ Example 3 >

A negative electrode was prepared in the same manner as in Example 1 except that only the natural graphite was used as the negative active material in the second coating layer.

<Example 4>

A negative electrode was prepared in the same manner as in Example 1 except that natural graphite and SiO 2 (90:10 by weight) were used as the negative electrode active material in the third coating layer.

&Lt; Comparative Example 1 &

A negative electrode was prepared in the same manner as in Example 1, except that the conductive material and the binder were mixed in a weight ratio of 4: 6 in the first coating layer.

&Lt; Comparative Example 2 &

A negative electrode was prepared in the same manner as in Example 1 except that natural graphite and SiO 2 (95: 5 by weight) were used as the negative electrode active material in the second coating layer.

&Lt; Comparative Example 3 &

A negative electrode was prepared in the same manner as in Example 1 except that natural graphite and SiO 2 (50:50 by weight) were used as the negative electrode active material in the second coating layer.

&Lt; Comparative Example 4 &

A negative electrode was prepared in the same manner as in Example 1, except that in the third coating layer, the negative electrode active material, the conductive material, and the binder were used in a weight ratio of 98: 0.5: 1.5.

&Lt; Comparative Example 5 &

A negative electrode was prepared in the same manner as in Example 1 except that the average thickness ratio of the first coating layer, the second coating layer and the third coating layer was 3: 3: 7.

<Experimental Example 1>

LiCoO ₂ , a conductive material (Denka black), and a binder (PVdF) were mixed in a NMP ratio of 96.5: 2.0: 1.5 by weight, respectively, as the positive electrode active material and the negative electrode prepared in Example 1-4 and Comparative Example 1-5, A positive electrode mixture was prepared, coated on an aluminum foil, rolled and dried, and a polyethylene film was interposed as a separator between the positive and negative electrodes. To the solvent of EC: EMC: DEC = 3: 2: 5 was added 1M LiPF ₆ , and 1.5% by weight of VC and 5% by weight of FEC as an electrolyte additive based on the total weight of the electrolyte.

The secondary battery was charged and discharged at a rate of 1 C / 1 C in the range of 2.7 to 4.35 V, and after 100 cycles, the change of charge / discharge capacity and the thickness of the battery were measured and are shown in Table 1 below.

After 100 cycles
Remaining capacity (%) Thickness increase rate after 100 cycles (%) Example 1 90.2 5.6 Example 2 91.3 5.55 Example 3 92.1 5.2 Example 4 87.0 8.8 Comparative Example 1 82.2 7.3 Comparative Example 2 80.7 11.3 Comparative Example 3 23.6 102.6 Comparative Example 4 83.7 32.7 Comparative Example 5 88.3 26.5

According to Table 1, the secondary battery including the anode manufactured according to Example 1-3 according to the present invention had a residual capacity (%) after 100 cycles as compared with the secondary battery including the anode manufactured according to Comparative Example 1-5. And the thickness increase rate (%) after 100 cycles. In the case of Example 4, however, the residual capacity (%) after 100 cycles is relatively low as compared with Comparative Example 5, but the thickness increase rate (%) after 100 cycles is much lower, indicating that the present invention has an intended effect .

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (20)

A negative electrode mixture layer containing a negative electrode active material, a binder and a conductive material is formed on the negative electrode collector,
The negative electrode material mixture layer may be formed,
A first coating layer in contact with the negative electrode current collector, the first coating layer including a conductive material and a binder;
A second coating layer comprising a carbon-based material or a negative electrode active material containing a carbon-based material and a silicon-based material, a conductive material, and a binder; And
Which has a relatively high content ratio of a silicon-based material, a conductive material and a binder, the carbon-based material and the silicon-based material being relatively thinner than the average thickness of the second coating layer, Coating layer;
And a negative electrode for a secondary battery. The negative electrode for a secondary battery according to claim 1, wherein the content of the binder in the first coating layer is 10% by weight to 40% by weight based on the total weight of the first coating layer. The method according to claim 1, wherein the binder of the first coating layer is selected from the group consisting of Carboxymethylcellulose (PVA), Polyvinyl alcohol (PVDF), Polyvinylpyrrolidone (PVD), Methyl cellulose (MC) Wherein the negative electrode is at least one selected from the group consisting of a positive electrode and a negative electrode. The negative electrode for a secondary battery according to claim 1, wherein the content of the silicon-based material in the negative electrode active material of the second coating layer is 3 wt% or less based on the total weight of the negative electrode active material of the second coating layer. The negative electrode for a secondary battery according to claim 4, wherein the content of the silicon-based material in the negative electrode active material of the second coating layer is 1 wt% or less based on the total weight of the negative electrode active material of the second coating layer. The negative electrode for a secondary battery according to claim 1, wherein the content of the silicon-based material in the negative electrode active material of the third coating layer is 5 wt% or more and 20 wt% or less based on the total weight of the negative electrode active material of the third coating layer. The negative electrode for a secondary battery according to claim 6, wherein the content of the silicon-based material in the negative electrode active material of the third coating layer is 10 wt% or more and 15 wt% or less based on the total weight of the negative electrode active material of the third coating layer. The negative electrode for a secondary battery according to claim 1, wherein the average thickness of the third coating layer is 3% to 40% of the average thickness of the second coating layer. The negative electrode for a secondary battery according to claim 1, wherein an average thickness of the second coating layer is 50% to 95% of an average thickness of the negative electrode material mixture layer. The negative electrode for a secondary battery according to claim 1, wherein an average thickness of the first coating layer is relatively thinner than an average thickness of the third coating layer. The negative electrode for a secondary battery according to claim 1, wherein the binder of the second coating layer and the third coating layer comprises SBR and / or CMC. The negative electrode for a secondary battery according to claim 1, wherein the content ratio of the binder in the third coating layer is relatively higher than the content ratio of the binder in the second coating layer. The negative electrode for a secondary battery according to claim 1, wherein the content of the binder in the third coating layer is 3% by weight or more and 20% by weight or less based on the total weight of the third coating layer. The secondary battery according to claim 1, wherein the carbon-based material is one or more selected from the group consisting of graphite, artificial graphite, MCMB (MesoCarbon MicroBead), carbon fiber, carbon black acetylene black, cathode. The method of claim 1, wherein the silicon-based material is selected from the group consisting of silicon, an alloy of silicon, SiB ₄ , SiB ₆ , Mg ₂ Si, Ni ₂ Si, TiSi ₂ , MoSi ₂ , CoSi ₂ , NiSi ₂ , CaSi ₂ , CrSi ₂ , Cu ₅ Si, FeSi ₂ , MnSi ₂ , NbSi ₂ , TaSi ₂ , VSi ₂ , WSi ₂ , ZnSi ₂ , SiC, Si ₃ N ₄ , Si ₂ N ₂ O, SiO _v (0.5 ≦ _v ≦ 1.2) Wherein the negative electrode is at least one selected from the group consisting of a positive electrode and a negative electrode. The negative electrode for a secondary battery according to claim 1, wherein the silicon-based material is SiO _v (0.5? _V ? 1.2). The method according to claim 1, wherein the negative electrode material mixture layer is formed in the order of a first coating layer, a second coating layer and a third coating layer on the negative electrode collector, or in the order of a first coating layer, a third coating layer and a second coating layer And a negative electrode for a secondary battery. A secondary battery comprising a negative electrode for a secondary battery according to claim 1. The secondary battery according to claim 18, wherein the secondary battery is a lithium secondary battery. 19. A device according to claim 18, comprising at least one secondary battery.