[One]Cross-Citation with Related Application(s) [2] This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0045583 on April 18, 2019, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification. [3] [4] technical field [5] The present invention relates to a non-aqueous electrolyte additive for a lithium secondary battery capable of inhibiting transition metal elution by forming a stable film on the surface of a positive electrode, and a non-aqueous electrolyte for a lithium secondary battery and a lithium secondary battery comprising the same. background [6] Recently, as personal IT devices and computer networks are developed due to the development of the information society, and the overall society's dependence on electric energy increases accordingly, technology development for efficiently storing and utilizing electric energy is required. [7] In particular, as interest in solving environmental problems and realization of a sustainable circulation type society has emerged, research on power storage devices such as non-aqueous electrolyte secondary batteries and electric double layer capacitors typified by lithium ion batteries has been extensively conducted. [8] Among them, lithium ion batteries can be miniaturized enough to be applied to personal IT devices, and because of their high operating voltage and energy density, they are used not only as power sources for notebook computers and mobile phones, but also as electric vehicles and power storage devices. These lithium ion batteries have high energy density compared with lead batteries and nickel-cadmium batteries, and are expected because high capacity is realized. [9] However, a lithium ion battery has a problem that the capacity of the battery decreases with the passage of a charge/discharge cycle. [10] Accordingly, as a method of suppressing a decrease in the capacity of a battery with the passage of a charge/discharge cycle, a method of adding various additives to the electrolyte is being studied. [11] The additive forms a film called a solid electrolyte interface (SEI) on the electrode surface while decomposing during the initial charge and discharge. Since the SEI is formed during the initial charge/discharge cycle, electricity for decomposition of a solvent or the like is not consumed, and lithium ions may travel to and from the electrode through the SEI. That is, the formation of the SEI prevents deterioration of an electrical storage device such as a nonaqueous electrolyte secondary battery when a charge/discharge cycle is repeated, thereby improving battery characteristics, storage characteristics, or load characteristics. [12] On the other hand, as the film formed on the surface of the electrode deteriorates when the battery is driven under high voltage and high temperature atmosphere, the structure of the surface of the anode collapses due to a side reaction between the nonaqueous electrolyte and the anode, and transition metal ions contained in the anode are eluted into the nonaqueous electrolyte problem arises. [13] As such, when the amount of impurities on the metal inside the battery increases, it is re-electrodeposited on the positive electrode, causing an increase in the resistance of the positive electrode, or conversely, after being transferred to the negative electrode through the electrolyte, it is electro-deposited on the negative electrode to dendrite ), which eventually causes an internal short circuit of the battery. Alternatively, it is known as a factor of consuming lithium ions or increasing the interfacial resistance of the negative electrode while accelerating an additional electrolyte decomposition reaction by destroying the SEI film imparting passivation ability to the negative electrode. [14] Accordingly, there is a need to develop a non-aqueous electrolyte having a new configuration capable of suppressing the elution of anode transition metals during battery driving under high voltage and high temperature atmosphere, suppressing low voltage failure and thus preventing deterioration of battery life. [15] Prior art literature [16] Korean Patent Publication No. 2017-0018975 DETAILED DESCRIPTION OF THE INVENTION technical challenge [17] An object of the present invention is to provide a non-aqueous electrolyte additive for a lithium secondary battery capable of inhibiting transition metal elution by forming a stable film on the surface of an anode in order to solve the above problems. [18] Another object of the present invention is to provide a non-aqueous electrolyte for a lithium secondary battery including the non-aqueous electrolyte additive. [19] Another object of the present invention is to provide a lithium secondary battery comprising the non-aqueous electrolyte for a lithium secondary battery. means of solving the problem [20] According to one embodiment, the present invention provides a non-aqueous electrolyte additive for a lithium secondary battery, which is a compound represented by the following formula (1): [21] [Formula 1] [22] [23] In Formula 1, [24] Y is a substituted or unsubstituted C1-C10 alkylene group. [25] [26] According to another embodiment, the present invention provides a non-aqueous electrolyte for a lithium secondary battery comprising a lithium salt, a non-aqueous organic solvent, and the non-aqueous electrolyte additive for a lithium secondary battery. [27] [28] According to another embodiment, the present invention provides a lithium secondary battery comprising the non-aqueous electrolyte for a lithium secondary battery. Effects of the Invention [29] The compound represented by Formula 1 used as a non-aqueous electrolyte additive for lithium secondary batteries of the present invention is a compound containing at least one cyano group in its structure, and forms a stable film on the surface of the positive electrode to prevent elution of transition metals, By suppressing a side reaction between the electrolyte and the electrolyte, it is possible to reduce the content of metal impurities inside the battery. [30] Therefore, if the non-aqueous electrolyte for a lithium secondary battery including the non-aqueous electrolyte additive for a lithium secondary battery is used, a lithium secondary battery having improved battery swelling and capacity characteristics can be implemented during high voltage and high temperature storage. Best mode for carrying out the invention [31] Hereinafter, the present invention will be described in more detail. [32] 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. [33] [34] In the case of a lithium ion battery, as the non-aqueous electrolyte is decomposed during initial charging and discharging, a film having a passivation ability is formed on the surfaces of the positive and negative electrodes to improve high-temperature storage characteristics. However, as the film deteriorates during high voltage and high temperature storage, the transition metal element is eluted from the anode, and thus the expression capacity may decrease due to the loss of the metal element. In addition, in the case of the eluted transition metal ions, they not only consume electrons by electrodeposition on the cathode reacting in a strong reduction potential band, but also destroy the SEI film when electrodeposited. As a result, an additional electrolyte decomposition reaction is caused while the surface of the anode is exposed, and consequently, irreversible capacity increases and the capacity of the cell continuously decreases. [35] Accordingly, in the present invention, a non-aqueous electrolyte additive capable of forming a stable film on the surface of the anode to prevent elution of transition metals, suppressing side reactions between the anode and the electrolyte, and reducing the metal impurity content inside the battery, and a non-aqueous electrolyte containing the same would like to provide In addition, an object of the present invention is to provide a lithium secondary battery having improved battery swelling and capacity characteristics during high voltage and high temperature storage by including the non-aqueous electrolyte. [36] [37] Non-aqueous electrolyte additive for lithium secondary battery [38] First, in the present invention, it is intended to provide a non-aqueous electrolyte additive that can form a passivation film on the surface of the anode to protect the surface of the anode under high voltage by containing one or more cyano groups, and has excellent adsorption effect with metal foreign substances. [39] That is, in the present specification, a compound represented by the following formula (1) is provided as a non-aqueous electrolyte additive for a lithium secondary battery: [40] [Formula 1] [41] [42] In Formula 1, [43] Y may be a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms. [44] In this case, in Formula 1, Y may be a substituted or unsubstituted C2 to C8 alkylene group, specifically, a substituted or unsubstituted C4 to C8 alkylene group. [45] More specifically, the compound represented by Formula 1 may be at least one selected from the group consisting of compounds represented by Formulas 1a to 1c below. [46] [Formula 1a] [47] [48] [49] [Formula 1b] [50] [51] [52] [Formula 1c] [53] [54] [55] Since the compound represented by Formula 1 includes at least one polar cyano group (ie, -CN, nitrile group) having a high dipole moment at both ends in the structure, it forms a stronger bond with the surface of the anode at high temperature to form a complex By forming a structure or ligand, it is possible to form a stable ion conductive film on the surface of the anode. [56] In particular, the cyano group adsorbs with metal ions such as Co, Mn, or Ni eluted from the positive electrode by repeated charging and discharging of the battery or chemical dissolution reaction of the electrolyte, or adsorbs with metal foreign substances mixed in raw materials or during the manufacturing process there is a high tendency to Accordingly, a structure in which one or more cyano groups are substituted on a silicon element like the compound represented by Formula 1 above, for example, based on a Si-CN bond providing a stable chemical bond, each containing three -CN terminal groups in Si In the case of a compound having a structure, the binding energy and binding site with metal ions increase compared to the nitrile-based compound used as an existing additive, so the effect of inhibiting metal elution from the positive electrode, for example, the effect of inhibiting the generation of metal ions inside the battery is excellent. . [57] Therefore, even when a small amount is applied, a stable film is formed on the surface of the anode to suppress the elution of metal foreign substances from the anode, and furthermore, the generation of gas generated by the side reaction between the anode and the electrolyte is suppressed, so that the battery swells at high voltage and high temperature storage. Ring and capacity characteristics can be further improved. [58] Moreover, in addition to adsorption of metal ions, the cyano group stabilizes the anion of the salt by the unshared electrons of N, thereby suppressing the generation of HF due to salt decomposition, and preventing a part of the transition metal from eluting and precipitating from the surface of the anode when stored at high temperature. can [59] In the compound represented by Formula 1, the length of a chain between the Si element and the Si element is preferably 10 or less carbon atoms. That is, when the chain length exceeds 10 carbon atoms, there is a disadvantage in that the compounds are aggregated with each other and solubility in an organic solvent is lowered. Therefore, in Formula 1, when the chain length between the Si element and the Si element satisfies the range of 1 to 10 carbon atoms, the electron cloud becomes more abundant and the electrostatic interaction with the metal cation ), the binding energy with the metal ion increases. [60] [61] Non-aqueous electrolyte for lithium secondary battery [62] Further, in one embodiment of the present invention, it is possible to provide a non-aqueous electrolyte for a lithium secondary battery comprising the non-aqueous electrolyte additive of the present invention, a lithium salt, and a non-aqueous organic solvent. [63] [64] (1) Non-aqueous electrolyte additive [65] The non-aqueous electrolyte of the present invention includes the compound represented by Formula 1 as described above as a non-aqueous electrolyte additive. [66] At this time, since the description of the non-aqueous electrolyte additive overlaps with the above-mentioned content, the description thereof will be omitted. [67] However, with respect to the non-aqueous electrolyte additive content, the compound represented by Formula 1 as the non-aqueous electrolyte additive is 0.1 wt% to 9 wt%, specifically 0.5 wt% to 5 wt%, based on the total weight of the non-aqueous electrolyte for lithium secondary batteries, More specifically, it may be included in an amount of 1 wt% to 5 wt%, more specifically 3 wt% to 5 wt%. [68] [69] When the compound represented by Formula 1 is included in the above range, it is possible to form a stable film on the surfaces of the negative electrode and the positive electrode, and also it is possible to manufacture a secondary battery with improved overall performance by implementing an excellent effect of inhibiting metal elution. . If the content of the compound represented by Formula 1 is less than 0.1 wt %, it is possible to remove metal foreign substances from the inside of the battery, but it is difficult to continuously maintain the effect, so the effect of removing metal inhibition decreases over time can be In addition, if the additive content exceeds 9% by weight, the metal elution inhibiting effect is improved, while the ionic conductivity decreases due to the increase in the viscosity of the non-aqueous electrolyte, which adversely affects the mobility of ions in the battery, resulting in deterioration of rate characteristics and low-temperature lifespan characteristics can be [70] Preferably, the compound represented by Formula 1 is included in 0.5 wt% to 5 wt%, specifically 1 wt% to 5 wt%, more specifically 3 wt% to 5 wt%, capacity reduction and resistance due to side reactions, etc. While suppressing the increase as much as possible, it is possible to more effectively implement the optimal effect of inhibiting the elution of metal and the effect of inhibiting the increase in the battery. [71] [72] (2) lithium salt [73] As the lithium salt, those commonly used in electrolytes for lithium secondary batteries may be used without limitation, for example, including Li + as a cation and F - , Cl - , Br - , I - , NO 3 - , N(CN) 2 - , BF 4 - , ClO 4 - , B 10 Cl 10 - , AlCl 4 - , AlO 2 - , PF 6 - , CF 3 SO 3 - , CH 3CO 2 - , CF 3 CO 2 - , AsF 6 - , SbF 6 - , CH 3 SO 3 - , (CF 3 CF 2 SO 2 ) 2 N - , (CF 3 SO 2 ) 2 N - , (FSO 2 ) 2 N - , BF 2 C 2 O 4 - , BC 4 O 8 - , PF 4 C 2 O 4 - , PF 2 C 4 O 8 - , (CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3 ) 4 PF 2 - , (CF 3 ) 5 PF - , (CF 3) 6 P - , C 4 F 9 SO 3 - , CF 3 CF 2 SO 3 - , CF 3 CF 2 (CF 3 ) 2 CO - , (CF 3 SO 2 ) 2 CH - , CF 3 (CF 2 ) 7 SO 3 - and SCN -At least one selected from the group consisting of may be mentioned. [74] Specifically, the lithium salt is LiCl, LiBr, LiI, LiBF 4 , LiClO 4 , LiB 10 Cl 10 , LiAlCl 4 , LiAlO 2 , LiPF 6 , LiCF 3 SO 3 , LiCH 3 CO 2 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiCH 3 SO 3 , LiFSI (Lithium bis(fluorosulfonyl)imide, LiN(SO 2 F) 2), LiBETI (lithium bisperfluoroethanesulfonimide, LiN(SO 2 CF 2 CF 3 ) 2 and LiTFSI (lithium (bis)trifluoromethanesulfonimide, LiN(SO 2 CF 3 ) 2 ) may contain a single substance or a mixture of two or more types. In addition to these, lithium salts commonly used in electrolytes for lithium secondary batteries can be used without limitation. [75] The lithium salt can be appropriately changed within the range that can be used in general, but to be included in the electrolyte at a concentration of 0.8 M to 4.0 M, specifically, at a concentration of 1.0 M to 3.0 M, in order to obtain an optimal effect of forming a film for preventing corrosion of the electrode surface. can [76] If the concentration of the lithium salt is less than 0.8 M, the effect of improving the low-temperature output of the lithium secondary battery and improving the cycle characteristics during high-temperature storage is insignificant. can [77] [78] (3) non-aqueous organic solvent [79] The non-aqueous organic solvent may include at least one organic solvent selected from the group consisting of a cyclic carbonate-based organic solvent, a linear carbonate-based organic solvent, a linear ester-based organic solvent, and a cyclic ester-based organic solvent. [80] Specifically, the organic solvent may include a cyclic carbonate-based organic solvent, a linear carbonate-based organic solvent, or a mixed organic solvent thereof. [81] The cyclic carbonate-based organic solvent is a high-viscosity organic solvent, which has a high dielectric constant and can well dissociate lithium salts in the electrolyte, and specific examples thereof include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene. At least one organic solvent selected from the group consisting of carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate and vinylene carbonate, among them, ethylene carbonate may include [82] In addition, the linear carbonate-based organic solvent is an organic solvent having a low viscosity and a low dielectric constant, and representative examples thereof include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate ( EMC), at least one organic solvent selected from the group consisting of methyl propyl carbonate and ethyl propyl carbonate may be used, and specifically, ethyl methyl carbonate (EMC) may be included. [83] In addition, the organic solvent is a linear ester-based organic solvent and a cyclic ester in at least one carbonate-based organic solvent selected from the group consisting of the cyclic carbonate-based organic solvent and the linear carbonate-based organic solvent in order to prepare an electrolyte having high ionic conductivity. At least one or more ester-based organic solvents selected from the group consisting of organic solvents may be further included. [84] Specific examples of the linear ester-based organic solvent include at least one organic solvent selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate and butyl propionate. can be heard [85] In addition, the cyclic ester-based organic solvent includes at least one organic solvent selected from the group consisting of γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone and ε-caprolactone. can [86] Meanwhile, as the organic solvent, an organic solvent commonly used in an electrolyte for a lithium secondary battery may be added without limitation, if necessary. For example, at least one organic solvent of an ether-based organic solvent, an amide-based organic solvent, and a nitrile-based organic solvent may be further included. [87] [88] (4) Additives for SEI film formation [89] In addition, the non-aqueous electrolyte for a lithium secondary battery of the present invention prevents the anode from disintegrating due to decomposition of the non-aqueous electrolyte in a high-output environment, or has low-temperature high-rate discharge characteristics, high-temperature stability, overcharge prevention, and battery expansion inhibition effect at high temperature. In order to improve it, if necessary, additives for forming SEI may be further included in the non-aqueous electrolyte. [90] The SEI-forming additive is a typical example of a cyclic carbonate-based compound, a halogen-substituted carbonate-based compound, a sultone-based compound, a sulfate-based compound, a phosphate-based compound, a borate-based compound, a nitrile-based compound, a benzene-based compound, an amine-based compound, silane At least one additive for forming an SEI film selected from the group consisting of a compound-based compound and a lithium salt-based compound may be included. [91] The cyclic carbonate-based compound may include vinylene carbonate (VC) or vinylethylene carbonate. [92] The halogen-substituted carbonate-based compound may include fluoroethylene carbonate (FEC)). [93] The sultone-based compound includes 1,3-propane sultone (PS), 1,4-butane sultone, ethenesultone, 1,3-propene sultone (PRS), 1,4-butene sultone, and 1-methyl-1,3 - at least one compound selected from the group consisting of propene sultone. [94] The sulfate-based compound may include ethylene sulfate (Esa), trimethylene sulfate (TMS), or methyl trimethylene sulfate (MTMS). [95] The phosphate-based compound is lithium difluoro (bisoxalato) phosphate, lithium difluorophosphate, tetramethyl trimethyl silyl phosphate, trimethyl silyl phosphite, tris (2,2,2-trifluoroethyl) phosphate and tris and at least one compound selected from the group consisting of (trifluoroethyl) phosphite. [96] The borate-based compound may include tetraphenylborate and lithium oxalyldifluoroborate. [97] The nitrile-based compound is succinonitrile, adiponitrile, acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentane carbonitrile, cyclohexane carbonitrile, 2-fluorobenzo At least one selected from the group consisting of nitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile compounds can be mentioned. [98] The benzene-based compound may include fluorobenzene, the amine-based compound may include triethanolamine or ethylenediamine, and the silane-based compound may include tetravinylsilane. [99] The lithium salt-based compound is a compound different from the lithium salt included in the non-aqueous electrolyte, and is selected from the group consisting of LiPO 2 F 2 , LiODFB, LiBOB (lithium bisoxalatoborate (LiB(C 2 O 4 ) 2 ) and LiBF 4 ). one or more compounds may be mentioned. [100] Among these SEI-forming additives, when vinylene carbonate, vinylethylene carbonate, or succinonitrile is additionally included, a more robust SEI film may be formed on the surface of the anode during the initial activation process of the secondary battery. [101] When the LiBF 4 is included, generation of a gas that may be generated due to the decomposition of the electrolyte at a high temperature is suppressed, thereby improving the high-temperature stability of the secondary battery. [102] [103] Meanwhile, the SEI forming additives may be used in a mixture of two or more, and may be included in an amount of 0.01 to 50% by weight, specifically 0.01 to 10% by weight, preferably 0.05 to 5% by weight based on the total weight of the non-aqueous electrolyte. % can be When the content of the SEI-forming additive is less than 0.01 wt%, the effect of improving the low-temperature output and high-temperature storage characteristics and high-temperature lifespan characteristics of the battery is insignificant, and when the content of the SEI-forming additive exceeds 50 wt%, the battery During charging and discharging, there is a possibility that side reactions in the electrolyte may be excessively generated. In particular, when the additives for forming the SEI film are added in excess, they may not be sufficiently decomposed at a high temperature, and thus may remain unreacted or precipitated in the electrolyte at room temperature. Accordingly, a side reaction in which the lifespan or resistance characteristic of the secondary battery is deteriorated may occur. [104] [105] lithium secondary battery [106] In another embodiment of the present invention, there is provided a lithium secondary battery comprising the non-aqueous electrolyte for a lithium secondary battery of the present invention. [107] The lithium secondary battery of the present invention may be manufactured by forming an electrode assembly in which a positive electrode, a negative electrode, and a separator are sequentially stacked between the positive and negative electrodes, stored in a battery case, and then by adding the non-aqueous electrolyte of the present invention. [108] The positive electrode, the negative electrode and the separator included in the lithium secondary battery of the present invention may be manufactured and applied according to a conventional method known in the art, and will be described in detail below. [109] [110] (1) Anode [111] The positive electrode may be prepared by coating a positive electrode slurry including a positive electrode active material, a binder, a conductive material and a solvent on a positive electrode current collector, followed by drying and rolling. [112] 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. [113] The positive active material is a compound capable of reversible intercalation and deintercalation of lithium, and specifically, may include a lithium composite metal oxide including lithium and one or more metals such as cobalt, manganese, nickel or aluminum. have. [114] More specifically, the lithium composite metal oxide is a lithium-manganese oxide (eg, LiMnO 2 , LiMn 2 O 4 , etc.), a lithium-cobalt-based oxide (eg, LiCoO 2 , etc.), lithium-nickel-based oxide (eg, LiNiO 2 , etc.), lithium-nickel-manganese oxide (eg, LiNi 1-Y Mn Y O 2 (0