Cross Citation with Related Applications [2] This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0142862 filed on November 19, 2018, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification. [3] technical field [4] The present invention relates to an anode active material and a lithium secondary battery including the same, and more particularly, to an anode active material to which a conductive material is stably attached by an organic connector and an elastic polymer, and a lithium secondary battery including the same. background [5] Due to the rapid increase in the use of fossil fuels, the demand for the use of alternative energy or clean energy is increasing. [6] Currently, a secondary battery is a representative example of an electrochemical device using such electrochemical energy, and its use area is gradually expanding. Recently, as technology development and demand for portable devices such as portable computers, portable phones, and cameras increase, the demand for secondary batteries as an energy source is rapidly increasing, and among such secondary batteries, high energy density, that is, high capacity lithium secondary batteries A lot of research has been done on it, and it has been commercialized and widely used. [7] In general, a secondary battery is composed of a positive electrode, a negative electrode, an electrolyte, and a separator. A metal oxide such as LiCoO 2 , LiMnO 2 , LiMn 2 O 4 or LiCrO 2 is used as a positive active material constituting the positive electrode of a lithium secondary battery, and as a negative active material constituting the negative electrode, metal lithium, graphite (graphite) ) or a carbon-based material such as activated carbon, or a material such as silicon oxide (SiO x ) is used. Among the anode active materials, metallic lithium was mainly used in the beginning, but as the charging and discharging cycle proceeds, lithium atoms grow on the surface of metallic lithium to damage the separator and damage the battery. Recently, carbon-based materials are mainly used. However, in the case of a carbon-based material, the theoretical capacity is only about 400 mAh/g, so it has a disadvantage that the capacity is small. Various studies are being conducted to replace the carbon-based material using a material. [8] However, a material having a high capacity has a problem in that the volume changes excessively during the charging and discharging process, causing an electrical short in the electrode, and the growth of a thick and unstable solid electrolyte interface (SEI), which deteriorates the performance of the battery. [9] Conventionally, in order to solve this problem, a method of forming a carbon coating layer on the surface of silicon-based particles or using an additional conductive material has been attempted. [10] However, the method of forming the carbon coating layer requires a process of applying heat when forming the carbon coating layer, so there is a problem in that the silicon-based particles are cracked or the pores are reduced, so that the efficiency is reduced. When this is increased, there is a problem that agglomeration between the conductive materials occurs. [11] Accordingly, as disclosed in Korean Patent Application Laid-Open No. 10-2016-0149862, a method of further controlling the volume change by further disposing a polymer composite on the carbon coating layer was attempted. However, even if the polymer composite is additionally formed, it is not easy to control the volume change, and on the contrary, the conductivity of the active material is lowered, thereby increasing resistance and lowering the capacity retention rate of the battery. In addition, since the silicon-based particles are excessively coated, it is difficult to absorb lithium ions, which leads to a decrease in capacity. [12] Therefore, there is a demand for the development of a new technology capable of solving problems such as electrical short circuit and performance degradation in the electrode due to the volume change of the high-capacity anode active material. [13] [Prior art literature] [14] [Patent Literature] [15] Laid-open Patent Publication No. 10-2016-0149862 DETAILED DESCRIPTION OF THE INVENTION technical challenge [16] SUMMARY OF THE INVENTION An object of the present invention is to provide a high-capacity anode active material having excellent conductivity without an electrical short circuit in an electrode. [17] Another object of the present invention to be solved is to provide a method of manufacturing the negative active material. [18] Another object of the present invention to be solved is to provide a negative electrode including the negative active material and a lithium secondary battery including the negative electrode. means of solving the problem [19] In order to solve the above problems, the present invention provides an active material core capable of intercalating and releasing lithium ions; a conductive material positioned on the surface of the active material core; an organic linker connecting the active material core and the conductive material; and an elastic polymer covering at least a portion of the active material core and the conductive material, wherein the conductive material includes at least one selected from the group consisting of a linear conductive material and a planar conductive material, and the organic connector has a hydrophobic structure and Provided is an anode active material, which is a compound including a substituent including a polar functional group. [20] In addition, in order to solve the other problem, the present invention provides the steps of (1) dispersing an active material core particle, a conductive material and an organic linker in a solvent, and placing the conductive material on the surface of the active material core particle; (2) mixing and stirring the active material core particles on the surface of the conductive material obtained in step (1) with a polymer precursor and a curing agent; and (3) agitating and curing the polymer precursor to form an elastic polymer on at least a portion of the active material core surface, wherein the conductive material includes a linear conductive material, a planar conductive material, or both, and the organic The linker is a compound including a substituent including a hydrophobic structure and a polar functional group, and provides a method for preparing the negative active material. [21] In addition, in order to solve the another problem, the present invention provides a negative electrode for a lithium secondary battery including the negative active material and a lithium secondary battery including the negative electrode. Effects of the Invention [22] In the negative active material according to the present invention, a conductive material is attached to the surface of an active material core in which lithium ions can be occluded and released through an organic connector, and an elastic polymer covers at least a portion of the active material core and the conductive material, the organic connection The conductive material is firmly bonded to the surface of the anode active material through the sieve, and the elastic polymer is deformed in association with the volume change of the anode active material, so that the conductive material can provide continuous electrical conductivity on the surface of the active material core, thus exhibiting improved stability and high-capacity lithium It can be usefully used in the manufacture of secondary batteries. Brief description of the drawing [23] 1 is a graph evaluating the capacity retention rates of Example 1 and Comparative Examples 1 to 3; Modes for carrying out the invention [24] Hereinafter, the present invention will be described in more detail to help the understanding of the present invention. [25] The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention. [26] As used herein, the term 'polycyclic ring' refers to a condensed ring, a condensed ring, and a condensed nucleus, which is a ring in which two or more rings share two or more atoms, respectively, unless otherwise noted. ) means [27] As used herein, the term 'alkyl group' refers to a straight-chain, cyclic or branched hydrocarbon residue, unless otherwise specified. [28] The term 'linear conductive material' as used herein, unless otherwise stated, means a conductive material having a fibrous structure such as a cylindrical type or a tube type, and the 'planar conductive material' is flat, sheet-like, It means a flaky conductive material, and 'point-shaped conductive material' means a generally used conductive material having a generally spherical particle shape. [29] [30] [31] The present invention provides an anode active material, specifically, an anode active material for a lithium secondary battery. [32] An anode active material according to the present invention includes an active material core capable of intercalating and deintercalating lithium ions; a conductive material positioned on the surface of the active material core; an organic linker connecting the active material core and the conductive material; and an elastic polymer covering at least a portion of the active material core and the conductive material, wherein the conductive material includes at least one selected from the group consisting of a linear conductive material and a planar conductive material, and the organic connector has a hydrophobic structure and It is a compound containing a substituent containing a polar functional group. [33] The linear or planar conductive material is generally difficult to be dispersed in a solvent, and when it is introduced into the surface of the negative electrode active material or the negative electrode, it is difficult to introduce it in a uniformly dispersed form due to aggregation caused by attractive forces between the conductive materials. Therefore, when using a linear conductive material or a planar conductive material, a dispersant is usually used together, but most dispersants are based on a weak attraction between materials. is difficult to form, and when the volume of the anode active material changes during charging and discharging, the conductive material falls off the surface of the anode active material. In this case, it is difficult to avoid deterioration of battery performance despite the introduction of a linear conductive material or a planar conductive material in order to maintain appropriate conductivity in response to a change in the volume of the negative active material. [34] In order to solve the above problems, the negative active material of the present invention firmly attaches the conductive material to the surface of the active material core through the organic connector, so that the conductive material stably provides electrical conductivity even when the volume of the negative active material changes. have. [35] In addition, in the negative active material of the present invention, the elastic polymer can provide additional bonding strength by covering at least a portion of the active material core and the conductive material with an elastic polymer, and a conductive material including a linear conductive material, a planar conductive material, or a mixture thereof It can allow materials to maintain an electrical network. [36] [37] The active material core is not particularly limited as long as it is a material capable of intercalating and releasing lithium ions, but the effect of including the organic connector and the linear conductive material is more preferably exhibited when the material has a high capacity and a large volume change during charging and discharging. can be The active material core capable of occluding and releasing lithium ions may be at least one selected from the group consisting of Si, SiO x (0 [87] In addition, the present invention provides an anode for a lithium secondary battery comprising the anode active material described above and a lithium secondary battery comprising the anode for a lithium secondary battery. [88] Specifically, the negative electrode for the lithium secondary battery includes a negative electrode current collector; and a negative electrode active material layer formed on the negative electrode current collector, wherein the negative electrode active material layer includes a negative electrode material including the negative electrode active material and a binder. [89] The negative current collector is not particularly limited as long as it has high conductivity without causing a chemical change in the battery. Specifically, the negative electrode current collector may be copper, stainless steel, aluminum, nickel, titanium, calcined carbon, one in which the surface of copper or stainless steel is surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. may be used. have. [90] The negative electrode current collector may typically have a thickness of 3 to 100 μm. [91] The negative electrode current collector may form fine concavities and convexities on the surface to strengthen the bonding strength of the negative electrode active material. For example, the negative electrode current collector may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a nonwoven body, and the like. [92] The negative electrode active material layer is formed on the negative electrode current collector, and includes a negative electrode material and a binder including the negative electrode active material described above. [93] The negative electrode material may further include a carbon-based active material together with the negative electrode active material described above. The carbon-based active material may impart excellent cycle characteristics or battery life performance to the negative electrode or secondary battery of the present invention. [94] Specifically, the carbon-based active material includes at least one selected from the group consisting of graphite, artificial graphite, natural graphite, hard carbon, soft carbon, carbon black, acetylene black, Ketjen black, super P, graphene, and fibrous carbon. and preferably at least one selected from the group consisting of graphite, artificial graphite, and natural graphite. [95] The anode material may be included in the anode active material layer in an amount of 60 wt% to 99 wt%, preferably 65 wt% to 90 wt%. [96] The negative active material layer includes a binder. The binder is polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (polyvinylidenefluoride), polyacrylonitrile (polyacrylonitrile), polyacrylamide (polyacrylamide) polymethylmethacrylic Polymethylmethacrylate, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer (EPDM) ), sulfonated EPDM, styrene butadiene rubber (SBR), fluororubber, polyacrylic acid, and at least one selected from the group consisting of a material in which hydrogen is substituted with Li, Na or K, etc. and may also include various copolymers thereof. [97] The binder may be included in the anode active material layer in an amount of 0.5 wt% to 30 wt%, preferably 5 wt% to 25 wt%. [98] The negative active material layer may include an additional conductive material. [99] The additional conductive material is not particularly limited as long as it has conductivity without causing a chemical change 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, farness black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; conductive tubes such as carbon nanotubes; metal powders such as fluorocarbon, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and at least one selected from the group consisting of conductive materials such as polyphenylene derivatives, preferably graphite such as natural graphite or artificial graphite; and carbon black such as carbon black, acetylene black, Ketjen black, channel black, farness black, lamp black, thermal black, etc.; at least one selected from the group consisting of may be used. [100] The additional conductive material may be included in the negative active material layer in an amount of 0.5 wt% to 25 wt%, preferably 3 wt% to 20 wt%. [101] The thickness of the negative active material layer may be 10 μm to 200 μm, preferably 20 μm to 150 μm. [102] [103] The negative electrode for a lithium secondary battery may be prepared by coating a negative electrode slurry including a negative electrode material, a binder, and a conductive material and/or a solvent for forming a negative electrode slurry on the negative electrode current collector, followed by drying and rolling. [104] The solvent for forming the negative electrode slurry includes an organic solvent such as NMP (N-methyl pyrrolidone), DMF (dimethyl formamide), acetone, dimethyl acetamide, or water, and these solvents are used alone or in a mixture of two or more. can be used by [105] [106] In addition, the present invention is a negative electrode for a lithium secondary battery described above; a positive electrode opposite to the negative electrode for the lithium secondary battery; a separator interposed between the negative electrode for the lithium secondary battery and the positive electrode; and an electrolyte; provides a lithium secondary battery comprising. [107] The negative electrode for the lithium secondary battery has been described above. [108] The positive electrode is formed on a positive electrode current collector and the positive electrode current collector, and may include a positive electrode active material layer including the positive electrode active material. [109] In the positive electrode, the positive electrode current collector is not particularly limited as long as it has conductivity without causing a chemical change in the battery, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or carbon on the surface of aluminum or stainless steel. , nickel, titanium, silver, etc. may be used. In addition, the positive electrode current collector may typically have a thickness of 3 μm to 500 μm, and may increase the adhesion of the positive electrode active material by forming fine irregularities on the surface of the current collector. For example, it may be used in various forms, such as a film, a sheet, a foil, a net, a porous body, a foam, a nonwoven body. [110] The positive active material may be a commonly used positive active material. Specifically, the positive active material is lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), Li[Ni x Co y Mn z Mv]O 2 (wherein M is from the group consisting of Al, Ga and In) any one selected or two or more of them; 0.3≤x<1.0, 0≤y, z≤0.5, 0≤v≤0.1, x+y+z+v=1), Li (Li a M ba-b' M' b' )O 2-c A c(Wherein, 0≤a≤0.2, 0.6≤b≤1, 0≤b'≤0.2, 0≤c≤0.2; M is Mn and Ni, Co, Fe, Cr, V, Cu, Zn and Ti. It includes at least one member selected from the group consisting of; M' is at least one member selected from the group consisting of Al, Mg and B, and A is at least one member selected from the group consisting of P, F, S and N layered compounds such as ) or compounds substituted with one or more transition metals; Lithium manganese oxides such as Formula Li 1+y Mn 2-y O 4 (where y is 0 to 0.33), LiMnO 3 , LiMn 2 O 3 , and LiMnO 2 ; lithium copper oxide (Li 2 CuO 2 ); LiV 3 O 8 , LiFe 3 O 4 , V 2 O 5 , Cu vanadium oxides such as 2 V 2 O 7 ; Ni site-type lithium nickel oxide represented by the formula LiNi 1-y M y O 2 (wherein M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and y is 0.01 to 0.3); Formula LiMn 2-y M y O 2 (wherein M = Co, Ni, Fe, Cr, Zn or Ta, and y is 0.01 to 0.1) or Li 2 Mn 3 MO 8 (where M = Fe, Co, lithium manganese composite oxide represented by Ni, Cu or Zn; 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 ) 3These etc. are mentioned, However, It is not limited only to these. The anode may be Li-metal. [111] The positive electrode active material layer may include a positive electrode conductive material and a positive electrode binder together with the above-described positive active material. [112] In this case, the positive electrode conductive material is used to impart conductivity to the electrode, and in the configured battery, it can be used without any particular limitation as long as it has electronic conductivity without causing chemical change. Specific examples include graphite such as natural graphite and artificial graphite; carbon-based materials such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, summer black, and carbon fiber; metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive whiskeys such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or a conductive polymer such as a polyphenylene derivative, and the like, and one or a mixture of two or more thereof may be used. [113] In addition, the positive electrode binder serves to improve adhesion between the positive electrode active material particles and the adhesive force between the positive electrode active material and the positive electrode current collector. Specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC) ), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene butadiene rubber (SBR), fluororubber, or various copolymers thereof, and any one of them or a mixture of two or more thereof may be used. [114] [115] The separator separates the anode and the anode and provides a passage for lithium ions to move, and it can be used without any particular limitation as long as it is normally used as a separator in a secondary battery. Excellent is preferred. Specifically, a porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene/butene copolymer, an ethylene/hexene copolymer, and an ethylene/methacrylate copolymer, or these A laminate structure of two or more layers of may be used. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high melting point glass fiber, polyethylene terephthalate fiber, or the like may be used. In addition, in order to secure heat resistance or mechanical strength, a coated separator containing a ceramic component or a polymer material may be used, and may optionally be used in a single-layer or multi-layer structure. [116] The electrolyte may include, but is not limited to, an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel polymer electrolyte, a solid inorganic electrolyte, and a molten inorganic electrolyte, which can be used in manufacturing a lithium secondary battery. [117] Specifically, the electrolyte may include a non-aqueous organic solvent and a metal salt. [118] As the non-aqueous organic solvent, for example, N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butylolactone, 1,2-dimethyl ethoxyethane, tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, Methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, ether, pyropion An aprotic organic solvent such as methyl acid or ethyl propionate may be used. [119] In particular, among the carbonate-based organic solvents, ethylene carbonate and propylene carbonate, which are cyclic carbonates, are highly viscous organic solvents and have a high dielectric constant and thus well dissociate lithium salts. If the same low-viscosity, low-dielectric constant linear carbonate is mixed in an appropriate ratio, an electrolyte having high electrical conductivity can be prepared, which can be used more preferably. [120] A lithium salt may be used as the metal salt, and the lithium salt is a material that is easily soluble in the non-aqueous electrolyte. For example, as an anion of the lithium salt , F - , Cl - , I - , NO 3 - , N(CN) ) 2 - , BF 4 - , ClO 4 - , PF 6 - , (CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3 ) 4 PF 2 - , (CF 3 )) 5 PF - , (CF 3 ) 6 P - , CF 3 SO 3 - , CF 3 CF 2 SO 3 - , (CF 3 SO 2 ) 2 N - , (FSO 2 ) 2 N - , CF 3 CF 2 ( CF 3 ) 2 CO - , (CF 3 )SO 2 ) 2 CH - , (SF 5 ) 3 C - , (CF 3 SO 2 ) 3 C - , CF 3 (CF 2 ) 7 SO 3 - , CF 3 CO 2 - , CH 3 CO 2 - , SCN - and (CF 3 CF 2 SO 2 ) 2At least one selected from the group consisting of N − may be used. [121] In addition to the electrolyte components, the electrolyte includes, for example, haloalkylene carbonate-based compounds such as difluoroethylene carbonate, pyridine, tri Ethyl phosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone, N,N-substituted imida One or more additives such as jolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxy ethanol or aluminum trichloride may be further included. [122] [123] According to another embodiment of the present invention, there is provided a battery module including the secondary battery as a unit cell and a battery pack including the same. Since the battery module and the battery pack include the secondary battery having high capacity, high rate-rate characteristic and cycle characteristic, a medium-to-large device selected from the group consisting of an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, and a system for power storage can be used as a power source for [124] [125] Example [126] Hereinafter, preferred embodiments are presented to aid the understanding of the present invention, but the embodiments are merely illustrative of the present description and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and technical spirit of the present description, It goes without saying that such variations and modifications fall within the scope of the appended claims. [127] [128] Example 1 [129] 0.03 g of 1-pyrenebutyric acid (PBA) was dissolved in a mixture of 100 g of 0.5 M aqueous NaOH solution and 30 g of ethanol. After putting 0.003 g of single-walled carbon nanotubes (SWNT) in the prepared solution, and performing probe-type sonication for 30 minutes, 1 g of Si powder was put into the prepared solution and ultrasonically dispersed for 30 minutes, Stirring was performed for 1 hour. The dispersion solution prepared in this way was filtered, and washing was performed through filtration while pouring water several times. The obtained material was dried in a vacuum oven at 130° C. for 12 hours to obtain 0.3% Si/PBA/SWNT (represents the wt% of SWNT relative to Si). [130] The obtained Si/PBA/SWNT 0.3% and poly(dimethyl siloxane) (PDMS) oligomer precursor were added to an acetone solvent in a weight ratio of 90:10, stirred for 1 hour, and then the curing agent was added in an amount of 10% by weight compared to the PDMS oligomer precursor. In addition, the reaction was carried out while stirring at 60° C. for 24 hours to form a PDMS elastic polymer on the Si/PBA/SWNT 0.3% surface. [131] This was filtered, washed and dried to finally prepare a negative active material of Si/PBA/SWNT 0.3%-PDMS. The PDMS is included in the negative active material in an amount of 10% by weight. [132] A negative electrode for battery performance evaluation was prepared using the prepared negative active material as follows. [133] Si/PBA/SWNT 0.3%-PDMS, graphite, Super-C and polyacrylic acid (PAA ) were added to water (H 2 O) in a weight ratio of 70:5:5:20 to prepare a slurry, which was then applied to copper foil. After coating and vacuum drying at about 65° C. for 2 hours, vacuum drying at about 130° C. for 12 hours to prepare a negative electrode. [134] [135] Comparative Example 1 [136] 0.3% of Si/PBA/SWNT prepared in Example 1 was used as the negative active material of Comparative Example 1. [137] A negative electrode for battery performance evaluation was prepared using the prepared negative active material as follows. As an anode active material, 0.3% Si/PBA/SWNT, graphite, Super-C and polyacrylic acid (PAA ) were added to water (H 2 O) in a weight ratio of 70:5:5:20 to prepare a slurry, which was then applied to copper foil. After coating and vacuum drying at about 65° C. for 2 hours, vacuum drying at about 130° C. for 12 hours to prepare a negative electrode. [138] [139] Comparative Example 2 [140] In Comparative Example 2, the Si and poly(dimethyl siloxane) (PDMS) oligomer precursor used in Example 1 was added to an acetone solvent in a weight ratio of 90:10, stirred for 1 hour, and then the curing agent was added in an amount of 10% by weight compared to the PDMS oligomer precursor. The amount was added, and the reaction was carried out while stirring at 60° C. for 24 hours to form a PDMS elastic polymer on the Si surface (Si-PDMS), which was used as the negative active material of Comparative Example 2. [141] A negative electrode slurry was prepared by mixing Si-PDMS, graphite, SWNT, Super-C, and PVDF in a weight ratio of 70:5:0.21:4.79:20 to prepare an anode in the same manner as in Example 1. [142] [143] Comparative Example 3 [144] Comparative Example 3 uses the Si-PDMS prepared in Comparative Example 2 as a negative active material, but Si-PDMS: graphite: SWNT: PBA: Super-C: PVDF = 68.5: 0.21: 2: 4.79: 20 mixed in a weight ratio of A negative electrode was prepared in the same manner as in Example 1 by preparing a negative electrode slurry. [145] [146] Experimental example [147] A coin-type half-cell was prepared using the negative electrodes prepared in Example 1 and Comparative Examples 1 to 3. Metal lithium foil was used as the positive electrode, and a polyethylene separator was interposed between the negative electrode and the positive electrode to prepare an electrode assembly. [148] After the electrode assembly was placed in a battery case, an electrolyte solution containing 1M LiPF 6 was injected into a non-aqueous solvent mixed in ethylene carbonate:diethyl carbonate=1:2 (volume ratio) to prepare a coin-type half-cell. [149] [150] Experimental Example 1: Battery charge and discharge characteristics [151] The charging and discharging characteristics of the coin-type half-cells prepared using the negative electrodes prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were evaluated. [152] In the first charge/discharge, the charge/discharge was performed at a current density of 0.1 C/0.1 C, and in the subsequent 30 times, the charge/discharge was performed at a current density of 0.5 C/0.5 C. The detailed conditions are as follows. At the time of charging, it was charged in the CC mode up to 50% of the 1C discharge capacity at the specified current density, and during discharging, the discharge was completed in the CC mode to 1 V at the specified current density. The capacity retention rate according to the cycle is shown in FIG. 1 . [153] [154] Referring to FIG. 1 , it can be seen that the cycle life characteristics of the secondary battery according to Example 1 are significantly improved compared to Comparative Examples 1 to 3. [155] Specifically, in the secondary battery according to Example 1, the conductive material is stably connected to the surface of the active material through the organic connector to form a conductive network, and at the same time, the elastic polymer (PDMS) has an appropriate area according to the volume expansion of the active material core. Since this change contributes to the improvement of the elasticity of the conductive network, it is considered that the lifespan characteristics are significantly improved compared to the comparative examples. [156] In addition, in the case of Comparative Example 1, since the elastic polymer is not covered with the used negative electrode active material, the effect of improving the elasticity of the conductive network is not expressed, and it can be seen that the life performance is reduced. [157] In addition, in the case of Comparative Example 2, since the active material core and the conductive material are not connected, it is difficult to stably form a conductive network that helps the electrical connection between the active materials, so that life performance is significantly reduced. [158] Further, in Comparative Example 3, 1-pyrene butyric acid was simply mixed in the negative electrode slurry, and 1-pyrene butyric acid could not function as an organic linker connecting the active material core and the conductive material. Accordingly, in the case of Comparative Example 3, it can be seen that it is difficult to stably form a conductive network that helps the electrical connection between the active materials, so that the lifespan performance is significantly reduced. Claims [Claim 1] an active material core capable of intercalating and deintercalating lithium ions; a conductive material positioned on the surface of the active material core; an organic linker connecting the active material core and the conductive material; and an elastic polymer covering at least a portion of the active material core and the conductive material, wherein the conductive material includes at least one selected from the group consisting of a linear conductive material and a planar conductive material, and the organic connector has a hydrophobic structure and A negative active material, which is a compound including a substituent including a polar functional group. [Claim 2] The negative active material of claim 1 , wherein the area of ​​the elastic polymer changes in association with a change in volume of the active material core, and the conductive material exhibits twisting and unfolding behavior according to the area change of the elastic polymer. [Claim 3] The negative active material of claim 1, wherein the elastic polymer is at least one selected from the group consisting of polysiloxane elastomer and thermoplastic polyester elastomer. [Claim 4] The negative active material of claim 1, wherein the conductive material is included in an amount of 0.05 to 10 parts by weight based on 100 parts by weight of the active material core. [Claim 5] The negative active material of claim 1, wherein the elastic polymer is contained in an amount of 0.1 wt% to 20 wt% in the negative active material. [Claim 6] The negative active material of claim 1 , wherein the hydrophobic structure comprises at least one selected from the group consisting of a π-electron conjugated ring and an alkylene structure having 3 to 20 carbon atoms. [Claim 7] The method of claim 1, wherein the linear conductive material is at least one selected from the group consisting of carbon fibers, carbon nanofibers (CNF), metal fibers, metal nanotubes, carbon nanotubes (CNTs), and conductive whiskers, and the planar conductive material comprises: At least one negative electrode active material selected from the group consisting of graphene, a metal thin film, and mxene. [Claim 8] The negative electrode of claim 1, wherein the active material core in which lithium ions can be occluded and released is Si, SiO x (0