[One]Cross-Citation with Related Application(s) [2]This application claims the benefit of priority based on Korean Patent Application No. 2019-0010027 dated January 25, 2019 and Korean Patent Application No. 2020-0008588 dated January 22, 2020, The content is incorporated as part of this specification. [3] [4] technical field [5] The present invention relates to an electrolyte for a lithium secondary battery having excellent high temperature characteristics and a lithium secondary battery including the same. background [6] 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] The secondary battery-based technology is the most suitable technology for various uses, and can be applied to personal IT devices because it can be miniaturized, and can also be applied to large devices such as power storage devices. [8] Among secondary battery technologies, a lithium ion battery, which is a battery system with the highest theoretical energy density, is in the spotlight. [9] Lithium ion batteries are largely composed of a positive electrode composed of a transition metal oxide containing lithium, a negative electrode capable of storing lithium, an electrolyte as a medium for transferring lithium ions, and a separator. As it is known as a component that has a great influence on stability and safety, many studies are being conducted on it. [10] On the other hand, during the activation process of the battery, the electrolyte causes a reductive decomposition reaction on the anode interface, and the reductive decomposition product forms a solid electrolyte interphase (SEI) film on the electrode interface that transmits lithium ions but inhibits further decomposition of the electrolyte. . [11] However, under high temperature conditions, the by-product generated by the decomposition reaction of the salt contained in the electrolyte is activated and then the SEI film formed on the surface of the anode and the cathode is decomposed again, thereby lowering the passivation ability of the SEI film, thereby further decomposing the electrolyte and thus There is a problem of causing concomitant self-discharge. [12] Accordingly, there is an urgent need to study an electrolyte capable of forming a strong SEI film without being damaged even by a side reaction by a decomposition product of a salt under a high temperature condition. [13] [14] Prior art literature [15] Korean Patent Publication No. 10-2017-0132239 DETAILED DESCRIPTION OF THE INVENTION technical challenge [16] The present invention is to solve the above problems, and relates to an electrolyte for a lithium secondary battery having improved high-temperature battery performance, and a lithium secondary battery including the same. means of solving the problem [17] According to one embodiment, the present invention, lithium salt; organic solvents; and an additive, wherein the additive provides an electrolyte for a lithium secondary battery comprising a compound represented by the following formula (1) and a compound represented by the following formula (2). [18] [Formula 1] [19] [20] In Formula 1, A is a substituted or unsubstituted heteroaryl group having 3 to 6 carbon atoms including at least one nitrogen element or a substituted or unsubstituted heteroaryl group having 3 to 6 carbon atoms including at least one nitrogen element. and a clicking group, and R 1 is a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms. [21] [Formula 2] [22] [23] (In Formula 2, [24] Wherein R 3 and R 4 are each independently selected from the group consisting of a linking group and an alkylene group having 1 to 3 carbon atoms, [25] Wherein X 1 to X 3 are each independently a halogen element, an alkyl group having 1 to 5 carbon atoms in which a halogen element is substituted or unsubstituted, an alkenyl group having 2 to 5 carbon atoms in which a halogen element is substituted or unsubstituted, or a halogen element is substituted or unsubstituted A cyclic alkynyl group having 2 to 5 carbon atoms and a halogen element are selected from the group consisting of a substituted or unsubstituted C 1 to C5 alkoxy group, at least one includes a halogen element, and n and m are each independently 0 or an integer of 1. [26] According to another embodiment, the present invention provides a positive electrode; cathode; and an electrolyte for the lithium secondary battery, wherein the negative electrode provides a lithium secondary battery comprising a carbon-based negative active material and a silicon-based negative active material. Effects of the Invention [27] The electrolyte for a lithium secondary battery according to the present invention can suppress a rapid increase in resistance under high-temperature conditions, can maintain a constant capacity, and improve high-temperature characteristics. [28] On the other hand, the electrolyte for a lithium secondary battery can form a strong SEI film on the negative electrode, so that an anode including a silicon-based active material having a large volume change in a high-temperature environment can be used, so the present invention has excellent capacity characteristics and excellent high-temperature characteristics A lithium secondary battery can be provided. Best mode for carrying out the invention [29] Hereinafter, the present invention will be described in more detail. [30] The terms or words used in the present specification and claims are not to 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. It should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention based on the principle that there is. [31] The terminology used herein is used to describe exemplary embodiments only, and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. [32] In the present specification, terms such as "comprise", "comprising" or "having" are intended to designate the presence of an embodied feature, number, step, element, or a combination thereof, but one or more other features or It should be understood that the existence or addition of numbers, steps, elements, or combinations thereof is not precluded in advance. [33] [34] [35] The electrolyte for a lithium secondary battery according to the present invention includes a lithium salt; organic solvents; and an additive, wherein the additive includes a compound represented by the following formula (1) and a compound represented by the following formula (2). [36] [Formula 1] [37] [38] In Formula 1, A is a substituted or unsubstituted heteroaryl group having 3 to 6 carbon atoms including at least one nitrogen element or a substituted or unsubstituted heteroaryl group having 3 to 6 carbon atoms including at least one nitrogen element. and a clicking group, and R 1 is a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms. [39] [40] [Formula 2] [41] [42] (In Formula 2, [43] Wherein R 3 and R 4 are each independently selected from the group consisting of a linking group and an alkylene group having 1 to 3 carbon atoms, [44] Wherein X 1 to X 3 are each independently a halogen element, an alkyl group having 1 to 5 carbon atoms in which a halogen element is substituted or unsubstituted, an alkenyl group having 2 to 5 carbon atoms in which a halogen element is substituted or unsubstituted, or a halogen element is substituted or unsubstituted A cyclic alkynyl group having 2 to 5 carbon atoms and a halogen element are selected from the group consisting of a substituted or unsubstituted C 1 to C5 alkoxy group, at least one includes a halogen element, and n and m are each independently 0 or an integer of 1. [45] [46] Hereinafter, each component of the electrolyte for a lithium secondary battery of the present invention will be described in more detail. [47] (1) lithium salt [48] First, the lithium salt will be described. [49] The lithium salt is used as a medium for transferring ions in the lithium secondary battery. Typically, the lithium salt is LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiClO 4 , LiN(C 2 F 5 SO 2 ) 2 , LiN(CF 3 SO 2 ) 2 , CF 3 SO 3 Li, LiC(CF) 3 SO 2 ) 3 , LiC 4 BO 8 , LiTFSI, LiFSI and LiClO 4It may include at least one compound selected from the group consisting of. [50] In this case, the lithium salt is preferably contained in the electrolyte for a lithium secondary battery at a concentration of 0.1M to 3M, preferably 0.8M to 2.5M, more preferably, 1M to 1.5M. When the lithium salt is included in the above range, while minimizing by-products generated by dissolution in the electrolyte, when the battery is driven under high voltage, the SEI (Solid Electrolyte Interphase, SEI) film formed on the electrode interface is prevented from decomposing, thereby preventing the battery It can prevent my resistance from rising. [51] [52] (2) organic solvents [53] Next, the organic solvent will be described. [54] In the present invention, the organic solvent is a solvent commonly used in lithium secondary batteries, for example, an ether compound, an ester (Acetate, Propionate) compound, an amide compound, a linear carbonate or a cyclic carbonate compound, a nitrile compound, etc. alone or a mixture of two or more. [55] Among them, a carbonate-based electrolyte solvent including a carbonate compound, which is typically a cyclic carbonate, a linear carbonate, or a mixture thereof may be used. [56] Specific examples of the cyclic carbonate compound include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene There is a single compound or a mixture of at least two or more selected from the group consisting of carbonate, vinylene carbonate, and halides thereof. In addition, specific examples of the linear carbonate compound include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethylmethyl carbonate (EMC), methylpropyl carbonate (MPC) and ethylpropyl carbonate (EPC) A compound selected from the group consisting of or a mixture of at least two or more may be representatively used, but the present invention is not limited thereto. [57] In particular, among the carbonate-based electrolyte solvents, propylene carbonate and ethylene carbonate, which are cyclic carbonates, are highly viscous organic solvents and have a high dielectric constant, so they can be used preferably because they dissociate lithium salts in the electrolyte well. Alternatively, when a low-viscosity, low-dielectric constant linear carbonate such as dimethyl carbonate is mixed in an appropriate ratio, an electrolyte having high electrical conductivity can be prepared, and thus it can be used more preferably. [58] In addition, esters in the electrolyte solvent include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, γ-valerolactone, γ-caprolactone, and σ-valerolactone. and a single compound or a mixture of at least two or more selected from the group consisting of ε-caprolactone, but is not limited thereto. [59] [60] (3) additives [61] Next, an additive is demonstrated. [62] The additive includes a compound represented by the following formula (1) and a compound represented by the following formula (2). [63] [Formula 1] [64] [65] In Formula 1, A is a substituted or unsubstituted heteroaryl group having 3 to 6 carbon atoms including at least one nitrogen element or a substituted or unsubstituted heteroaryl group having 3 to 6 carbon atoms including at least one nitrogen element. and a clicking group, and R 1 is a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms. [66] [67] [Formula 2] [68] [69] (In Formula 2, [70] Wherein R 3 and R 4 are each independently selected from the group consisting of a linking group and an alkylene group having 1 to 3 carbon atoms, [71] Wherein X 1 to X 3 are each independently a halogen element, an alkyl group having 1 to 5 carbon atoms in which a halogen element is substituted or unsubstituted, an alkenyl group having 2 to 5 carbon atoms in which a halogen element is substituted or unsubstituted, or a halogen element is substituted or unsubstituted A cyclic alkynyl group having 2 to 5 carbon atoms and a halogen element are selected from the group consisting of a substituted or unsubstituted C 1 to C5 alkoxy group, at least one includes a halogen element, and n and m are each independently 0 or an integer of 1. [72] [73] More specifically, the compound represented by Chemical Formula 1 may be selected from the group consisting of compounds represented by the following Chemical Formulas 1a to 1d. [74] [Formula 1a] [75] [76] In Formula 1a, R 1 is a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms , and R a is at least one selected from the group consisting of hydrogen, an alkyl group having 1 to 3 carbon atoms, and a cyano group. [77] [78] [Formula 1b] [79] [80] In Formula 1b, R 1 is a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms , and R b is at least one selected from the group consisting of hydrogen, an alkyl group having 1 to 3 carbon atoms, and a cyano group. [81] [82] [Formula 1c] [83] [84] In Formula 1c, R 1 is a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms , and R c is at least one selected from the group consisting of hydrogen, an alkyl group having 1 to 3 carbon atoms, and a cyano group. [85] [86] [Formula 1d] [87] [88] In Formula 1d, R 1 is a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms , and R d is at least one selected from the group consisting of hydrogen, an alkyl group having 1 to 3 carbon atoms, and a cyano group. [89] [90] More specifically, the compound represented by Formula 1 may be selected from the group consisting of compounds represented by Formulas 1e to 1h. [91] [Formula 1e] [92] [93] [94] [Formula 1f] [95] [96] [97] [Formula 1g] [98] [99] [100] [Formula 1h] [101] [102] [103] On the other hand, the compound represented by Formula 1 is 0.01 parts by weight to 2 parts by weight, preferably 0.05 parts by weight to 2 parts by weight, more preferably 0.05 parts by weight to 1 parts by weight based on 100 parts by weight of the electrolyte for a lithium secondary battery. may be included as a part. When the compound represented by Formula 1 is used, a stable film structure can be formed and decomposition by-products of salts in the battery can be removed, but components that increase battery resistance may be included in the film. Therefore, when the compound represented by Formula 1 is included within the above range, it is possible to effectively remove decomposition by-products of salt in the battery while minimizing the increase in resistance in the battery, and to stably form a negative electrode film. [104] [105] When the compound according to Formula 1 is used, HF and PF 5 generated when the salt is decomposed at high temperature are removed, thereby suppressing the occurrence of side reactions under high temperature conditions. In addition, by forming a stable film on the surface of the anode, it is possible to suppress the decomposition of the electrolyte at high temperature, thereby reducing the amount of gas generated according to the decomposition reaction, thereby improving the high-temperature safety of the battery. [106] However, when the compound according to Chemical Formula 1 is used, there is a problem in that a component having a high resistance is included in the film, thereby increasing the initial resistance of the battery. In addition, the compound according to Chemical Formula 1 cannot form a stable film on the surface of the anode as compared to the anode, so it is difficult to use alone. [107] Therefore, the inventors of the present invention have devised an electrolyte using the compound according to Chemical Formula 2 together with the compound according to Chemical Formula 1, which can suppress the increase in initial resistance and form a stable film on the surface of the anode. [108] [109] Specifically, the compound represented by Formula 2 may be a compound represented by Formula 2a below. [110] [Formula 2a] [111] [112] In Formula 2a, [113] Wherein X 1 to X 3 are each independently a halogen element, an alkyl group having 1 to 5 carbon atoms in which a halogen element is substituted or unsubstituted, an alkenyl group having 2 to 5 carbon atoms in which a halogen element is substituted or unsubstituted, or a halogen element is substituted or unsubstituted It is selected from the group consisting of a cyclic alkynyl group having 1 to 5 carbon atoms and an alkoxy group having 1 to 5 carbon atoms in which a halogen element is substituted or unsubstituted, and at least one may include a halogen element. [114] [115] As a more specific example, the compound represented by Formula 2 may be selected from the group consisting of compounds represented by Formulas 2b to 2h. [116] [Formula 2b] [117] [118] [119] [Formula 2c] [120] [121] [122] [Formula 2d] [123] [124] [125] [Formula 2e] [126] [127] [128] [Formula 2f] [129] [130] [131] [Formula 2g] [132] [133] [134] [Formula 2h] [135] [136] [137] Meanwhile, the compound represented by Formula 1 and the compound represented by Formula 2 may be included in a weight ratio of 2:0.5 to 2:23, but preferably 2:1 to 2 in order to prevent an increase in resistance after high-temperature charging and discharging. :20, more specifically 2:1 to 2:18 weight ratio, more preferably 2:1 to 2:16 weight ratio may be included in the electrolyte for a lithium secondary battery. When each of the compounds is included within the above range, a stable film is formed on the surface of the positive electrode while suppressing an increase in initial resistance caused by the compound represented by Formula 1, thereby improving the capacity and resistance characteristics of the battery. [138] [139] (4) additional additives [140] On the other hand, the electrolyte for a lithium secondary battery according to an embodiment of the present invention is a stable film on the surface of the negative electrode and the positive electrode without significantly increasing the initial resistance together with the effect expressed by the additive containing the compounds represented by the formulas 1 and 2 It may further include other additional additives capable of forming or inhibiting the decomposition of a solvent in the electrolyte for a lithium secondary battery, and serving as a complement to improve the mobility of lithium ions. [141] These other additional additives are not particularly limited as long as they are capable of forming a stable film on the surfaces of the positive electrode and the negative electrode. Representative examples thereof include phosphate or phosphite compounds, sulfate compounds, sultone compounds, lithium salt compounds, halogenated benzene compounds, sulfite compounds, sulfone compounds, halogen-substituted carbonate compounds, nitrile compounds, and borate compounds. It may include at least one selected from the group consisting of compounds, preferably at least one selected from the group consisting of a phosphate-based compound, a sulfate-based compound, a sultone-based compound, a lithium salt-based compound, and a halogenated benzene compound. have. [142] The phosphate-based or phosphite-based compound is electrochemically decomposed on the surface of the positive electrode and the negative electrode to help form an SEI film, and through this, an effect of improving the long-term cycle life characteristics of the secondary battery can be realized. Representative examples of such phosphate-based compounds include lithium difluoro (bisoxalato) phosphate, lithium difluorophosphate, tetramethyl trimethyl silyl phosphate (TMSPa), trimethyl silyl phosphite (TMSPi), and tris (2,2,2). and at least one compound selected from the group consisting of -trifluoroethyl)phosphate (TFEPa) and tris(trifluoroethyl)phosphite (TFEPi). [143] The sulfate-based compound may be ethylene sulfate (Esa), trimethylene sulfate (TMS), or methyl trimethylene sulfate (MTMS). [144] The sultone-based compound is 1,3-propane sultone (PS), 1,4-butane sultone, ethenesultone, 1,3-propene sultone (PRS), 1,4-butene sultone, and 1-methyl-1; It may be at least one compound selected from the group consisting of 3-propene sultone. [145] 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 ). It may be one or more compounds. [146] Examples of the halogenated benzene compound include fluorinated benzene and 1-4-dimethoxy-2-fluorobenzene. In the case of the halogenated benzene compound, an SEI film is formed on the surface of the anode/cathode during charging and discharging to suppress gas generation at high temperatures, and an insulating film is formed when the battery is overcharged, thereby suppressing the overcharge reaction. [147] The sulfite-based compound is ethylene sulfite, methyl ethylene sulfite, ethyl ethylene sulfite, 4,5-dimethyl ethylene sulfite, 4,5-diethyl ethylene sulfite, propylene sulfite, 4,5-dimethyl propylene sulfite at least one compound selected from the group consisting of phite, 4,5-diethyl propylene sulfite, 4,6-dimethyl propylene sulfite, 4,6-diethyl propylene sulfite, and 1,3-butylene glycol sulfite can be [148] The sulfone-based compound may be at least one compound selected from the group consisting of divinyl sulfone, dimethyl sulfone, diethyl sulfone, methylethyl sulfone, and methylvinyl sulfone. [149] The borate-based compound may be lithium oxalyldifluoroborate. [150] The halogen-substituted carbonate-based compound may be fluoroethylene carbonate (FEC)). [151] In addition, the nitrile-based compound is succinonitrile (SN), adiponitrile (Adn), acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptannitrile, cyclopentane carbonitrile, cyclohexane Carbonitrile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile It may be at least one compound selected from the group consisting of. [152] On the other hand, as other additives, the compounds listed above may be included alone or in mixture of two or more types, and the additive and the other additives including the compound represented by Formula 1 and the compound represented by Formula 2 and the other additives are electrolytes for lithium secondary batteries. It may be included in an amount of 20 parts by weight or less, specifically 10 parts by weight or less, based on 100 parts by weight. When the content of the additive and other additives exceeds 20 parts by weight, side reactions in the electrolyte may excessively occur during charging and discharging of the battery, and additives that are not sufficiently decomposed at high temperature are present or precipitated in an unreacted state. By increasing the initial resistance, the lifespan characteristics of the battery may be deteriorated. [153] [154] [155] Next, a lithium secondary battery according to the present invention will be described. [156] A lithium secondary battery according to an embodiment of the present invention includes a positive electrode, a negative electrode, and an electrolyte for the lithium secondary battery. At this time, since the electrolyte for a lithium secondary battery is the same as the above-described content, a detailed description thereof will be omitted. [157] [158] (1) Anode [159] The positive electrode may be prepared by coating a positive electrode active material slurry including a positive electrode active material, a binder for an electrode, a conductive material for an electrode, and a solvent on a positive electrode current collector. [160] 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 this case, the positive electrode current collector may form fine irregularities on the surface to strengthen the bonding force of the positive electrode active material, and may be used in various forms, such as a film, a sheet, a foil, a net, a porous body, a foam, a nonwoven body. [161] 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. 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-Y1 Mn Y1 O 2 (here, 0