KR20170112122A - Additive for lithium battery electrolytic solution, Organic electrolytic solution and Lithium battery comprising additive - Google Patents

Abstract

상기 식에서,
R₁ 및 R₂는 서로 독립적으로 할로겐; 할로겐으로 치환 또는 비치환된 탄소수 1 내지 5의 알킬기; 할로겐으로 치환 또는 비치환된 탄소수 1 내지 5의 알콕시기; 할로겐으로 치환 또는 비치화된 탄소수 4 내지 10의 시클로알킬기; 할로겐으로 치환 또는 비치환된 탄소수 5 내지 10의 아릴기; 할로겐으로 치환 또는 비치환된 탄소수 2 내지 10의 헤테로아릴기; 할로겐으로 치환 또는 비치환된 탄소수 2 내지 5의 알케닐기; 또는 할로겐으로 치환 또는 비치환된 탄소수 2 내지 5의 알키닐기이며,
R₁ 및 R₂는 서로 결합하여 고리를 형성할 수 있다.An additive for a lithium cell electrolyte, which is a phosphorous base compound represented by the following formula (1), an organic electrolytic solution containing the same, and a lithium battery are provided:
≪ Formula 1 >

In this formula,
R ₁ and R ₂ are independently of each other halogen; An alkyl group having 1 to 5 carbon atoms which is unsubstituted or substituted with halogen; An alkoxy group having 1 to 5 carbon atoms which is substituted or unsubstituted with halogen; A cycloalkyl group having 4 to 10 carbon atoms which is substituted or unsubstituted with halogen; An aryl group having 5 to 10 carbon atoms which is unsubstituted or substituted with halogen; A heteroaryl group having 2 to 10 carbon atoms which is unsubstituted or substituted with halogen; An alkenyl group having 2 to 5 carbon atoms which is substituted or unsubstituted with halogen; Or an alkynyl group having 2 to 5 carbon atoms which is substituted or unsubstituted with halogen,
R ₁ and R ₂ may combine with each other to form a ring.

Description

[0001] The present invention relates to an additive for a lithium battery electrolyte, an organic electrolyte solution containing the additive, and an additive for lithium battery electrolytic solution,

An additive for a lithium battery electrolyte, an organic electrolytic solution containing the same, and a lithium battery.

Lithium batteries are used as power sources for portable electronic devices such as video cameras, mobile phones, and notebook computers. The rechargeable lithium secondary battery has three times higher energy density per unit weight than conventional lead batteries, nickel-cadmium batteries, nickel metal hydride batteries and nickel-zinc batteries.

Since the lithium battery operates at a high driving voltage, an aqueous electrolyte having high reactivity with lithium can not be used. An organic electrolytic solution is generally used for a lithium battery. The organic electrolytic solution is prepared by dissolving a lithium salt in an organic solvent. It is preferable that the organic solvent is stable at a high voltage, has a high ionic conductivity and a high dielectric constant, and has a low viscosity.

When an organic electrolyte solution containing a lithium salt is used for a lithium battery, lifetime characteristics and high-temperature stability of the lithium battery may be deteriorated due to side reactions between the cathode / anode and the electrolyte.

Therefore, there is a demand for an organic electrolyte capable of providing a lithium battery having improved lifetime characteristics and high temperature stability.

One aspect is to provide an additive for a new lithium battery electrolyte.

One aspect is to provide an organic electrolytic solution containing the additive.

Another aspect of the present invention is to provide a lithium battery including the organic electrolytic solution.

According to one aspect,

There is provided an additive for a lithium battery electrolyte which is a phosphorous base compound represented by the following formula (1)

≪ Formula 1 >

In this formula,

R ₁ and R ₂ are independently of each other halogen; An alkyl group having 1 to 5 carbon atoms which is unsubstituted or substituted with halogen; An alkoxy group having 1 to 5 carbon atoms which is substituted or unsubstituted with halogen; A cycloalkyl group having 4 to 10 carbon atoms which is substituted or unsubstituted with halogen; An aryl group having 5 to 10 carbon atoms which is unsubstituted or substituted with halogen; A heteroaryl group having 2 to 10 carbon atoms which is unsubstituted or substituted with halogen; An alkenyl group having 2 to 5 carbon atoms which is substituted or unsubstituted with halogen; Or an alkynyl group having 2 to 5 carbon atoms which is substituted or unsubstituted with halogen,

R ₁ and R ₂ may combine with each other to form a ring.

According to another aspect,

A first lithium salt as an additive according to the above;

A second lithium salt; And

An organic electrolytic solution containing an organic solvent is provided.

According to another aspect,

anode; cathode; And

There is provided a lithium battery including the above organic electrolyte solution.

According to one aspect, by using an organic electrolyte solution containing a lithium salt, which is a phosphorus compound having a novel structure, lifetime characteristics and high temperature stability of the lithium battery can be improved.

FIG. 1 is a Nyquist plot showing the impedance measurement results of the lithium battery manufactured in Examples 7 and 10 and Comparative Examples 5 to 6. FIG.
FIG. 2 is a graph showing the normal temperature lifetime characteristics of the lithium battery manufactured in Example 7 and Comparative Examples 5 and 7. FIG.
3 is a graph showing high temperature lifetime characteristics of the lithium battery produced in Example 7 and Comparative Examples 5 and 7. FIG.
FIG. 4 is a graph showing the normal temperature lifetime characteristics of the lithium batteries produced in Examples 11 to 12 and Comparative Example 8. FIG.
5 is a graph showing the high temperature lifetime characteristics of the lithium batteries produced in Examples 11 to 12 and Comparative Example 8. FIG.
6 is a graph showing the capacity retention rate of the lithium battery produced in Example 11 and Comparative Example 8 after storage at 60 DEG C at high temperature.
7 is a graph showing a direct current resistance (DC-IR) of the lithium battery produced in Example 11 and Comparative Example 8 after storage at a high temperature of 60 캜.
8 is a schematic diagram of a lithium battery according to an exemplary embodiment.
Description of the Related Art
1: Lithium battery 2: cathode
3: anode 4: separator
5: Battery case 6: Cap assembly

Hereinafter, an electrolyte additive for a lithium battery according to exemplary embodiments, an organic electrolyte containing the same, and a lithium battery will be described in more detail.

An additive for a lithium battery electrolyte according to an embodiment includes a phosphorous base compound represented by the following Formula 1:

≪ Formula 1 >

Wherein R ₁ and R ₂ are independently of each other halogen; An alkyl group having 1 to 5 carbon atoms which is unsubstituted or substituted with halogen; An alkoxy group having 1 to 5 carbon atoms which is substituted or unsubstituted with halogen; A cycloalkyl group having 4 to 10 carbon atoms which is substituted or unsubstituted with halogen; An aryl group having 5 to 10 carbon atoms which is unsubstituted or substituted with halogen; A heteroaryl group having 2 to 10 carbon atoms which is unsubstituted or substituted with halogen; An alkenyl group having 2 to 5 carbon atoms which is substituted or unsubstituted with halogen; Or an alkynyl group having 2 to 5 carbon atoms which is substituted or unsubstituted with halogen, provided that at least one of R ₁ and R ₂ is an alkyl group or an alkoxy group, R ₁ and R ₂ may be bonded to each other to form a ring, A ₁ , A ₂ , A ₃ and A ₄ are independently of each other halogen.

The phosphorus compound is added to the electrolyte solution of the lithium battery to improve the battery performance such as lifetime characteristics and high temperature stability of the lithium battery.

The reason why the phosphorus compound is added to the electrolytic solution to improve the performance of the lithium battery will be described in more detail below. However, the scope of the present invention is not limited to the following description.

The lithium salt contained in the electrolyte of the lithium battery reacts with the organic solvent of the electrolyte to promote depletion of the organic solvent, generate a large amount of gas, and form a solid electrolyte interface layer (SEI layer) with high resistance. For example, when the organic electrolyte is exposed to a high temperature, LiPF _{6, which} is a kind of lithium salt in an electrolyte containing a small amount of water, is decomposed into LiF and PF ₆ , and they react with the organic solvent to consume the organic solvent, To elute metal ions. Therefore, the high-temperature stability and lifetime characteristics of the lithium battery are deteriorated.

The phosphorus compound can be coordinated to a thermal decomposition product of a lithium salt such as LiPF ₆ present in the organic electrolytic solution or an anion dissociated from a lithium salt to stabilize them. The side reactions of the organic electrolytic solution and the pyrolysis product of the lithium salt or the anion dissociated from the lithium salt can be suppressed. Therefore, lifetime characteristics and high-temperature stability of the lithium battery can be improved. In addition, the phosphorus compound suppresses side reactions of the organic electrolytic solution, so that the SEI layer and / or the protective layer having low resistance can be formed. Therefore, the internal resistance of the lithium battery can be reduced.

Therefore, the organic electrolytic solution containing the phosphorus compound provides stability to lithium batteries at a low temperature to a high temperature, for example, -30 ° C to 85 ° C, and can provide improved charge / discharge characteristics.

For example, when the phosphorus compound represented by Formula 1 is a phosphinate-based compound represented by Formula 2, a phosphate-based compound represented by Formula 3, or a phosphonate represented by Formula 4, phosphonate-based compounds:

(2) (3) ≪ Formula 4 >

Wherein R ₃ and R ₄ are independently of each other halogen; An alkyl group having 1 to 5 carbon atoms which is unsubstituted or substituted with halogen; A cycloalkyl group having 4 to 10 carbon atoms which is substituted or unsubstituted with halogen; An aryl group having 5 to 10 carbon atoms which is unsubstituted or substituted with halogen; A heteroaryl group having 2 to 10 carbon atoms which is unsubstituted or substituted with halogen; An alkenyl group having 2 to 5 carbon atoms which is substituted or unsubstituted with halogen; Or an alkynyl group having 2 to 5 carbon atoms which is substituted or unsubstituted with halogen, provided that at least one of R ₃ and R ₄ is an alkyl group or an alkoxy group, and R ₃ and R ₄ may combine with each other to form a ring.

For example, when the phosphorus compound represented by Formula 1 is a phosphinate-based compound represented by Formula 5, a phosphate-based compound represented by Formula 6, or a phosphonate represented by Formula 7 phosphonate-based compounds:

≪ Formula 5 > (6) ≪ Formula 7 >

Wherein R < ₅ > and R < ₆ > are independently from each other selected from the group consisting of halogen; Provided that at least one of R ₅ and R ₆ is an alkyl group, and R ₅ and R ₆ may combine with each other to form a ring.

For example, in Formula 1, R ₁ and R ₂ are each independently selected from the group consisting of F, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, , Propoxy group, isopropoxy group, butoxy group, isobutoxy group, tert-butoxy group or pentoxy group.

Specifically, the phosphorus compound represented by Formula 1 may be a compound represented by Formula 8 to 25:

(8) ≪ Formula 9 > ≪ Formula 10 >

≪ Formula 11 > ≪ Formula 12 > ≪ Formula 13 >

≪ Formula 14 > ≪ Formula 15 > ≪ Formula 16 >

≪ Formula 17 > ≪ Formula 18 > (19)

(20) ≪ Formula 21 > (22)

≪ Formula 23 > ≪ EMI ID = ≪ Formula 25 >

The organic electrolytic solution according to another embodiment includes the first lithium salt, which is the phosphorus compound additive described above; A second lithium salt; And organic solvents.

By including the phosphorus compound as an organic electrolyte in the above-described additive, battery performance such as lifetime characteristics and high temperature stability of the lithium battery including the organic electrolyte can be improved.

The content of the first lithium salt as an additive in the organic electrolytic solution may be 0.01 to 5% by weight based on the total weight of the organic electrolytic solution. However, the amount is not necessarily limited to this range. For example, the content of the first lithium salt as an additive in the organic electrolytic solution may be 0.05 to 5% by weight based on the total weight of the organic electrolytic solution. For example, the content of the first lithium salt as an additive in the organic electrolytic solution may be 0.05 to 4% by weight based on the total weight of the organic electrolytic solution. For example, the content of the first lithium salt as an additive in the organic electrolytic solution may be 0.05 to 3% by weight based on the total weight of the organic electrolytic solution. For example, the content of the first lithium salt as an additive in the organic electrolytic solution may be 0.1 to 2% by weight based on the total weight of the organic electrolytic solution. For example, the content of the first lithium salt as an additive in the organic electrolytic solution may be 0.1 to 1% by weight based on the total weight of the organic electrolytic solution. For example, the content of the first lithium salt as an additive in the organic electrolytic solution may be 0.1 to 0.5% by weight based on the total weight of the organic electrolytic solution. Further improved battery characteristics within the above range of contents can be obtained.

The organic electrolytic solution may further include a non-polar unsaturated group-containing cyclic carbonate compound. The non-polar unsaturated group-containing cyclic carbonate compound may contain a vinyl group, a vinylene group, or a combination of these with a non-polar unsaturated group.

For example, the non-polar unsaturated group-containing cyclic carbonate compound may be vinylene carbonate (VC); Vinylene carbonate substituted with at least one substituent selected from halogen, cyano group (CN) and nitro group (NO ₂ ); Vinyl ethylene carbonate (VEC); And vinylethylene carbonate substituted with at least one substituent selected from halogen, cyano group (CN) and nitro group (NO ₂ ). The non-polar unsaturated group-containing cyclic carbonate compound may be used alone, or two or more thereof may be used at the same time.

For example, the non-polar unsaturated group-containing cyclic carbonate compound may be vinylene carbonate (VC) and / or vinylethylene carbonate (VEC). Vinylene carbonate (VC) has a pentagonal structure with carbon having SP ² hybrid orbitals. Therefore, the vinylene carbonate (VC) may have high reactivity to change into a more stable structure due to the unstable structure due to high ring strain. Therefore, it can be easily reduced and / or decomposed by a ring-opening reaction at the time of initial charging to contribute to formation of a stable SEI layer.

The content of the non-polar group-containing cyclic carbonate compound in the organic electrolytic solution may be 0.01 to 5% by weight based on the total weight of the organic electrolytic solution, but is not necessarily limited to this range, and an appropriate amount may be used if necessary. For example, the content of the non-polar unsaturated cyclic carbonate compound in the organic electrolytic solution may be 0.1 to 4% by weight based on the total weight of the organic electrolytic solution. For example, the content of the non-polar unsaturated group-containing cyclic carbonate compound in the organic electrolytic solution may be 0.1 to 3.5% by weight based on the total weight of the organic electrolytic solution. For example, the content of the non-polar unsaturated cyclic carbonate compound in the organic electrolytic solution may be 0.1 to 3% by weight based on the total weight of the organic electrolytic solution. For example, the content of the non-polar unsaturated cyclic carbonate compound in the organic electrolytic solution may be 0.2 to 3% by weight based on the total weight of the organic electrolytic solution. For example, the content of the non-polar unsaturated group-containing cyclic carbonate compound in the organic electrolytic solution may be 0.3 to 3% by weight based on the total weight of the organic electrolytic solution. For example, the content of the non-polar unsaturated cyclic carbonate compound in the organic electrolytic solution may be 0.3 to 2% by weight based on the total weight of the organic electrolytic solution. Further improved battery characteristics within the above range of contents can be obtained.

In the organic electrolyte solution, the second lithium salt is LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , LiAlO ₂ , ₄ , LiN (C _x F _{2x + 1} SO ₂ ) (C _y F _{2y + 1} SO ₂ ) (x and y are each an integer of 1 to 20), LiCl, LiI or mixtures thereof, But is not limited to, and can be used as a lithium salt in the art.

The concentration of the second lithium salt in the organic electrolytic solution may be 0.01 to 2.0 M. For example, in the organic electrolyte solution, the concentration of the second lithium salt may be 0.05 to 2.0 M. For example, the concentration of the second lithium salt in the organic electrolytic solution may be 0.1 to 2.0 M. For example, in the organic electrolytic solution, the concentration of the second lithium salt may be 0.5 to 2.0 M, but the concentration is not necessarily limited to this range, and an appropriate concentration may be used if necessary. Further improved battery characteristics within the above range of concentration can be obtained.

In the organic electrolytic solution, the organic solvent may include a low boiling point solvent. The low boiling point solvent means a solvent having a boiling point of 200 캜 or less at 25 캜 and 1 atm.

For example, the organic solvent may include one or more selected from the group consisting of dialkyl carbonates, cyclic carbonates, linear or cyclic esters, linear or cyclic amides, aliphatic nitriles, linear or cyclic ethers, and derivatives thereof can do.

More specifically, the organic solvent is selected from the group consisting of ethyl methyl carbonate (EMC), methyl propyl carbonate, ethyl propyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, propylene carbonate ), Fluoroethylene carbonate (FEC), butylene carbonate, ethyl propionate, ethyl butyrate, acetonitrile, succinonitrile (SN), dimethylsulfoxide, dimethylformamide, dimethylacetamide, gamma-valerolactone, Gamma -butyrolactone, and tetrahydrofuran, but not always limited thereto, and any low-boiling solvent that can be used in the art can be used.

The organic electrolytic solution may be in a liquid or gel state. The organic electrolytic solution can be prepared by adding the phosphorus compound of Formula 1 and / or 2 (that is, the first lithium salt) and the second lithium salt to the organic solvent described above.

In the present specification, a and b of "carbon number a to b" mean the carbon number of a specific functional group. That is, the functional group may include a carbon atom from a to b. For example, "alkyl group of 1 to 4 carbon atoms" is an alkyl group having from 1 to 4 carbon atoms, _{i.e., CH 3 -, CH 3 CH} 2 -, CH 3 CH 2 CH 2 -, (CH 3) 2 CH-, CH ₃ CH ₂ CH ₂ CH ₂ -, CH ₃ CH ₂ CH (CH ₃ ) - and (CH ₃ ) ₃ C-.

Nomenclature for a particular radical may include mono-radical or di-radical depending on the context. For example, if a substituent requires two points of attachment to the remaining molecule, the substituent should be understood as a diradical. For example, two alkyl substituents identified by requiring a single connection point, _{?? CH 2 ??, ?? CH 2} CH 2 ??, ?? CH 2 CH (CH 3) CH 2 ??, such as di Radicals. Other radical nomenclature such as "akylene" clearly indicates that the radical is a di-radical.

As used herein, the term "alkyl group" or "alkylene group" refers to a branched or unbranched aliphatic hydrocarbon group. In one embodiment, the alkyl group may be substituted or unsubstituted. The alkyl group includes alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, But are not necessarily limited thereto, and each of them may be optionally substituted or unsubstituted. In one embodiment, the alkyl group may have from 1 to 5 carbon atoms. For example, the alkyl group having 1 to 5 carbon atoms may be methyl, ethyl, propyl, isopropyl, butyl, iso-butyl, sec-butyl, pentyl, 3-pentyl, hexyl and the like.

As used herein, the term "cycloalkyl group" means a fully saturated carbocycle ring or ring system. Means, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl.

As used herein, the term "alkenyl group" refers to a hydrocarbon group containing from 2 to 10 carbon atoms including at least one carbon-carbon double bond and includes an ethenyl group, a 1-propenyl group, Butenyl, 2-butenyl, cyclopropenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, and the like. In one embodiment, the alkenyl group may be substituted or unsubstituted. In one embodiment, the alkenyl group may have from 2 to 10 carbon atoms.

As used herein, the term "alkynyl group" refers to a hydrocarbon group containing from 2 to 10 carbon atoms including at least one carbon-carbon triple bond such as an ethynyl group, 1-propynyl group, 1-butynyl group, But are not limited to these. In one embodiment, the alkynyl group may be substituted or unsubstituted. In one embodiment, the alkynyl group may have from 2 to 10 carbon atoms.

As used herein, the term "aromatic" refers to a ring or ring system having a conjugated pi electron system and includes a carbon ring aromatic (e.g., phenyl) and a heterocyclic aromatic (e.g., pyridine) . The term includes monocyclic rings or fused polycyclic rings (i.e., rings that share adjacent pairs of atoms) if the whole ring system is aromatic.

As used herein, the term "aryl group" means an aromatic ring or ring system (ie, two or more fused rings sharing two adjacent carbon atoms) wherein the ring backbone contains only carbon. If the aryl group is a ring system, then each ring in the system is aromatic. For example, the aryl group includes, but is not limited to, a phenyl group, a biphenyl group, a naphthyl group, a phenanthrenyl group, a naphthacenyl group, and the like. The aryl group may be substituted or unsubstituted.

As used herein, the term "heteroaryl group" means an aromatic ring system having one ring or multiple fused rings, wherein at least one ring atom is not carbon, i.e., a heteroatom. In the fused ring system, one or more heteroatoms may be present in only one ring. For example, heteroatoms include, but are not necessarily limited to, oxygen, sulfur and nitrogen. For example, heteroaryl groups include furanyl, thienyl, imidazolyl, quinazolinyl, quinolinyl, isoquinolinyl, quinolinyl, quinolinyl, But are not limited to, quinoxalinyl, pyridinyl, pyrrolyl, oxazolyl, indolyl, and the like.

As used herein, the term "aralkyl group" or "alkylaryl group" means an aryl group connected as an substituent group via an alkylene group, such as an aralkyl group having 6 to 15 carbon atoms, and includes benzyl group, 2-phenylethyl group, 3- Phenylpropyl group, naphthylalkyl group, and the like. In one embodiment, the alkylene group is a lower alkylene group (i.e., an alkylene group of 1 to 5 carbon atoms).

As used herein, a "cycloalkenyl group" is a carbocycle ring or ring system having one or more double bonds, which is an aromatic ring-free ring system. For example, a cyclohexenyl group.

As used herein, a "heterocyclyl group" is a non-aromatic ring or ring system comprising at least one heteroatom in the ring skeleton.

As used herein, "halogen" is a stable element belonging to Group 17 of the Periodic Table of the Elements, for example, fluorine, chlorine, bromine or iodine, in particular fluorine and / or chlorine.

In the present specification, a substituent is derived by replacing one or more hydrogen atoms with other atoms or functional groups in a non-substituted mother group. Unless otherwise stated, when a functional group is considered "substituted ", it is meant that the functional group is selected from the group consisting of an alkyl group of 1 to 10 carbon atoms, an alkenyl group of 2 to 10 carbon atoms, a cycloalkyl group of 3 to 10 carbon atoms, An alkenyl group, an alkyl group having 1 to 10 carbon atoms, and an aryl group having 5 to 10 carbon atoms. When a functional group is described as "optionally substituted ", it is meant that the functional group may be substituted with the substituent described above.

A lithium battery according to another embodiment includes a positive electrode; A cathode, and an organic electrolytic solution according to the above. The form of the lithium battery is not particularly limited, and includes a lithium secondary battery such as a lithium ion battery, a lithium ion polymer battery, a lithium sulfur battery, and a lithium air battery, as well as a lithium primary battery.

For example, the lithium battery can be manufactured by the following method.

First, the anode is prepared.

For example, a cathode active material composition in which a cathode active material, a conductive material, a binder, and a solvent are mixed is prepared. The positive electrode active material composition is directly coated on the metal current collector to produce a positive electrode plate. Alternatively, the cathode active material composition may be cast on a separate support, and then the film peeled from the support may be laminated on the metal current collector to produce a cathode plate. The anode is not limited to those described above, but may be in a form other than the above.

The cathode active material is a lithium-containing metal oxide, and any of those conventionally used in the art can be used without limitation. For example, at least one of complex oxides of metal and lithium selected from cobalt, manganese, nickel, and combinations thereof may be used. Specific examples thereof include Li _a A _1-b B _b D ₂ In the formula, 0.90? A? 1.8, and 0? B? 0.5); Li _a E _1-b B _b O _{2 -c} D _c wherein, in the formula, 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05; LiE (in the above formula, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05) 2-b B b O 4-c D c; Li _a Ni _{1 -bc} Co _b B _c D _? Wherein, in the formula, 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _{1- b c} Co _b B _c O _{2 -?} F _? Wherein? 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _{1- b c} Co _b B _c O _2-α F ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α <2; Li _a Ni _1-bc Mn _b B _c D _? Wherein, in the formula, 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _1-bc Mn _b B _c O _2-α F _α wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α <2; Li _a Ni _1-bc Mn _b B _c O _2-α F ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α <2; Li _a Ni _b E _c G _d O ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, and 0.001 ≤ d ≤ 0.1; Li _a Ni _b Co _c Mn _d GeO ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, and 0.001 ≤ e ≤ 0.1; Li _a NiG _b O ₂ (in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1); Li _a CoG _b O ₂ wherein, in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1; Li _a MnG _b O ₂ (in the above formula, 0.90? A? 1.8, 0.001? B? 0.1); Li _a Mn ₂ G _b O ₄ wherein, in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1; QO _2; QS ₂ ; LiQS ₂ ; V ₂ O ₅ ; LiV ₂ O ₅ ; LiIO ₂ ; LiNiVO _4; Li _(3-f) J ₂ (PO ₄ ) ₃ (0? F? 2); Li _(3-f) Fe ₂ (PO ₄ ) ₃ (0? F? 2); In the formula of LiFePO ₄ may be used a compound represented by any one:

In the above formula, A is Ni, Co, Mn, or a combination thereof; B is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or combinations thereof; Q is Ti, Mo, Mn, or a combination thereof; I is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

For example, LiCoO ₂ , LiMn _x O _2x (x = 1, 2), LiNi _1-x Mn _x O _2x (0 <x <1), LiNi _1-xy Co _x Mn _y O ₂ 0.5, and 0≤y≤0.5), LiFePO ₄ or the like.

Of course, a compound having a coating layer on the surface of the compound may be used, or a compound having a coating layer may be mixed with the compound. The coating layer may comprise an oxide, a hydroxide of the coating element, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, or a coating element compound of the hydroxycarbonate of the coating element. The compound constituting these coating layers may be amorphous or crystalline. The coating layer may contain Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr or a mixture thereof. The coating layer forming step may be any coating method as long as it can coat the above compound by a method that does not adversely affect physical properties of the cathode active material (for example, spray coating, dipping, etc.) by using these elements, It will be understood by those skilled in the art that a detailed description will be omitted.

As the conductive material, carbon black, graphite fine particles, or the like may be used, but not limited thereto, and any material that can be used as a conductive material in the related art can be used.

Examples of the binder include vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethylmethacrylate, polytetrafluoroethylene and mixtures thereof, and styrene butadiene rubber-based polymers But are not limited thereto and can be used as long as they can be used as binders in the art.

As the solvent, N-methylpyrrolidone, acetone, water or the like may be used, but not limited thereto, and any solvent which can be used in the technical field can be used.

The content of the positive electrode active material, the conductive material, the binder and the solvent is a level commonly used in a lithium battery. Depending on the application and configuration of the lithium battery, one or more of the conductive material, the binder and the solvent may be omitted.

Next, the cathode is prepared.

For example, a negative electrode active material composition is prepared by mixing a negative electrode active material, a conductive material, a binder and a solvent. The negative electrode active material composition is directly coated on the metal current collector and dried to produce a negative electrode plate. Alternatively, the negative electrode active material composition may be cast on a separate support, and then the film peeled off from the support may be laminated on the metal current collector to produce a negative electrode plate.

The negative electrode active material may be any material that can be used as a negative electrode active material of a lithium battery in the related art. For example, at least one selected from the group consisting of a lithium metal, a metal capable of alloying with lithium, a transition metal oxide, a non-transition metal oxide, and a carbon-based material.

For example, the metal that can be alloyed with lithium is at least one element selected from the group consisting of Si, Sn, Al, Ge, Pb, Bi, Sb Si-Y alloys (Y is at least one element selected from the group consisting of alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, (Wherein Y is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, a rare earth element, or a combination element thereof, and not a Sn element) ) And the like. The element Y may be at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Se, Te, Po, or a combination thereof.

For example, the transition metal oxide may be lithium titanium oxide, vanadium oxide, lithium vanadium oxide, or the like.

For example, the non-transition metal oxide may be SnO ₂ , SiO _x (0 <x <2), or the like.

The carbon-based material may be crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon may be graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake, spherical or fibrous shape, and the amorphous carbon may be soft carbon or hard carbon carbon, mesophase pitch carbide, calcined coke, and the like.

The conductive material and the binder in the negative electrode active material composition may be the same as those in the positive electrode active material composition.

The content of the negative electrode active material, the conductive material, the binder and the solvent is a level commonly used in a lithium battery. Depending on the application and configuration of the lithium battery, one or more of the conductive material, the binder and the solvent may be omitted.

Next, a separator to be inserted between the positive electrode and the negative electrode is prepared.

The separator is usable as long as it is commonly used in a lithium battery. A material having low resistance against the ion movement of the electrolyte and excellent in the ability to impregnate the electrolyte may be used. For example, selected from glass fiber, polyester, Teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), or a combination thereof, and may be nonwoven fabric or woven fabric. For example, a rewindable separator such as polyethylene, polypropylene, or the like is used for the lithium ion battery, and a separator having excellent organic electrolyte impregnation capability can be used for the lithium ion polymer battery. For example, the separator may be produced according to the following method.

A polymer resin, a filler and a solvent are mixed to prepare a separator composition. The separator composition may be coated directly on the electrode and dried to form a separator. Alternatively, after the separator composition is cast and dried on a support, a separator film peeled from the support may be laminated on the electrode to form a separator.

The polymer resin used in the production of the separator is not particularly limited, and any material used for the binder of the electrode plate may be used. For example, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate or mixtures thereof may be used.

Next, the aforementioned organic electrolytic solution is prepared.

As shown in FIG. 8, the lithium battery 1 includes an anode 3, a cathode 2, and a separator 4. The anode 3, the cathode 2 and the separator 4 described above are wound or folded and housed in the battery case 5. Then, an organic electrolytic solution is injected into the battery case 5 and is sealed with a cap assembly 6 to complete the lithium battery 1. The battery case may have a cylindrical shape, a rectangular shape, a thin film shape, or the like. For example, the lithium battery may be a large-sized thin-film battery. The lithium battery may be a lithium ion battery.

A separator may be disposed between the anode and the cathode to form a battery structure. The cell structure is laminated in a bi-cell structure, then impregnated with an organic electrolyte solution, and the obtained result is received in a pouch and sealed to complete a lithium ion polymer battery.

In addition, a plurality of battery assemblies may be stacked to form a battery pack, and such battery pack may be used for all devices requiring high capacity and high output. For example, a notebook, a smart phone, an electric vehicle, and the like.

Further, the lithium battery is excellent in life characteristics and high-rate characteristics, and thus can be used in an electric vehicle (EV). For example, a hybrid vehicle such as a plug-in hybrid electric vehicle (PHEV). It can also be used in applications where a large amount of power storage is required. For example, an electric bicycle, a power tool, and the like.

The present invention will be described in more detail by way of the following examples and comparative examples. However, the examples are for illustrating the present invention, and the scope of the present invention is not limited thereto.

(Synthesis of Additive)

PREPARATION EXAMPLE 1 Synthesis of Compound (9)

Compounds of formula 9 below may be prepared according to Scheme 1 below.

<Reaction Scheme 1>

In a 1000 ml round flask, 700 ml of anhydrous acetone, 20 g (149 mmol) of yellowish brown lithium iodide (LiI) and 17.5 ml (149 mmol) of trimethyl phosphate were added and stirred in a glove box containing nitrogen (N ₂ ) The reaction mixture was reacted at room temperature for 5 days and 18 hours, followed by vacuum filtration to obtain a white reaction mixture.

The white reaction mixture was transferred to a 100 ml round-bottomed flask, placed in 50 ml of anhydrous acetone, stirred for 4 hours and 15 minutes, vacuum-filtered in a glove box, and dried to remove the residue to obtain white lithium phosphate (Llithium dimethyl phosphate) (89%)

¹ H NMR (300 MHz, D ₂ O): (3.54 (d, 6H) ³¹ P NMR (300 MHz, D ₂ O): (2.98).

&Lt; Formula 9 >

Preparation Example 2: Synthesis of Compound (10)

The compound of formula (10) may be prepared according to the following reaction scheme 2.

<Reaction Scheme 2>

25.03 (186.79 mmol) of yellowish brown lithium iodide (LiI) and 21 mL (24.08 g, 173.79 mmol) of colorless transparent dimethyl methyl phosphate were added to 800 ml of acetone and methyl iodide was removed from the glove box After 18 hours of adjusting the adapter to exit, a slightly bright yellow cloud form is observed. The reaction was then continued for 9 days and the white mixture obtained was then vacuum filtered to give a yellow product.

The resultant was washed again with 200 mL of acetone for 2 hours and then vacuum filtered again. The residue was removed twice to obtain lithium methyl methyl phosphonate (white).

¹ H NMR (300 MHz, D ₂ O): (3.47 (d, 3H), 1.20 (d, 3H), ³¹ P NMR (300 MHz, D ₂ O): 28.26.

&Lt; Formula 10 >

(Preparation of organic electrolytic solution)

Example 1: LiDMP 0.2 wt%

A mixed solution of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) in a volume ratio of 2: 4: 4 by volume was mixed with 1.15 M LiPF ₆ as a second lithium salt, 0.2% by weight of phosphorus compound was added to prepare an organic electrolytic solution.

&Lt; Formula 9 >

Example 2: LiDMP 0.5 wt%

An organic electrolytic solution was prepared in the same manner as in Example 1, except that the content of the phosphorous compound represented by Formula 9 was changed to 0.5 wt%.

Example 3: LiDMP 1.0 wt%

An organic electrolytic solution was prepared in the same manner as in Example 1, except that the content of the phosphorous compound represented by Formula 9 was changed to 1.0 wt%.

Example 4: LiMMP 0.2 wt%

To the mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) in a volume ratio of 2: 4: 4, 1.15 M LiPF ₆ as the second lithium salt and 0.2 weight % Was added to prepare an organic electrolytic solution.

&Lt; Formula 10 >

Example 5: LiDMP 0.2 wt% + VC 0.5 wt%

A mixture of 1.15 M LiPF ₆ as a second lithium salt and 0.2 weight% of a phosphorus compound represented by the above formula (9) were added to a 2: 4: 4 volume ratio mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) And 0.5% by weight of vinylene carbonate (VC) represented by the following formula (27) were added to prepare an organic electrolytic solution.

&Lt; Formula 9 > &Lt; Formula 27 >

Example 6 LiMMP 0.2 wt% + VC 0.5 wt%

To the mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) in a volume ratio of 2: 4: 4, 1.15 M LiPF ₆ as the second lithium salt, 0.2 weight% And 0.5% by weight of vinylene carbonate (VC) represented by the following formula (27) were added to prepare an organic electrolytic solution.

&Lt; Formula 10 > &Lt; Formula 27 >

Comparative Example 1: Control

An organic electrolytic solution was prepared by adding 1.15M LiPF ₆ to a mixed solvent of 2: 4: 4 by volume of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) and a second lithium salt.

Comparative Example 2: LiPO ₂ F ₂  0.2 wt%

A mixed solvent of ethylene carbonate (EC), ethylmethyl carbonate (EMC) and dimethyl carbonate (DMC) in a volume ratio of 2: 4: 4 was mixed with 1.15 M LiPF ₆ as a second lithium salt and lithium difluoro 0.2% by weight of lithium difluorophosphate (LiPO ₂ F ₂ ) was added to prepare an organic electrolytic solution.

(26)

Comparative Example 3: LiPO ₂ F ₂  1.0 wt%

An organic electrolytic solution was prepared in the same manner as in Comparative Example 2, except that the content of lithium difluorophosphate represented by Formula 327 was changed to 1.0% by weight.

Comparative Example 4: LiPO ₂ F ₂  1.0 wt% + VC 0.5 wt%

A mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) in a volume ratio of 2: 4: 4 was mixed with 1.15 M LiPF ₆ as a second lithium salt, lithium difluorophosphate 1.0% by weight of lithium difluorophosphate (LiPO ₂ F ₂ ) and 0.5% by weight of vinylene carbonate (VC) represented by the following chemical formula 27 were added to prepare an organic electrolytic solution.

(26) &Lt; Formula 27 >

(Production of lithium battery)

Example 7

(Cathode manufacture)

, 98% by weight of artificial graphite (BSG-L, Tianjin BTR New Energy Technology Co., Ltd.), 1.0% by weight of styrene-butadiene rubber (SBR) binder (ZEON) and 1.0% by weight of carboxymethylcellulose (CMC, NIPPON A & And the mixture was stirred for 60 minutes using a mechanical stirrer to prepare an anode active material slurry. The slurry was coated on a copper collector having a thickness of 10 mu m to a thickness of about 60 mu m using a doctor blade, dried in a hot air drier at 100 DEG C for 0.5 hour, dried again under vacuum at 120 DEG C for 4 hours, (roll press) to produce an anode plate.

(Anode manufacture)

_{LiNi 0.33 Co 0.33 Mn 0.33 O 2} 97.45 % by weight, as the conductive material of artificial graphite (SFG6, Timcal) powder, 0.5% by weight, carbon black (Ketjenblack, ECP) 0.7% by weight, nitrile rubber modified acrylic (BM-720H, Zeon Corporation ), 0.2 wt% of polyvinylidene fluoride (PVdF, S6020, Solvay), 0.9 wt% of polyvinylidene fluoride (PVdF, S6020, Solvay) and 0.2 wt% of polyvinylidene fluoride And the mixture was stirred for 30 minutes using a mechanical stirrer to prepare a cathode active material slurry. The slurry was coated on an aluminum current collector having a thickness of about 60 mu m with a doctor blade to a thickness of about 60 mu m and dried in a hot air drier at 100 DEG C for 0.5 hour and then dried again under vacuum at 120 DEG C for 4 hours, (roll press) to produce a positive electrode plate.

A 14 占 퐉 thick polyethylene separator coated with a ceramic on the anode side as a separator and a lithium battery using the organic electrolyte prepared in Example 1 as an electrolyte were prepared.

Examples 8 to 12

A lithium battery was prepared in the same manner as in Example 7 except that the organic electrolytes prepared in Examples 2 to 6 were used in place of the organic electrolytes prepared in Example 1, respectively.

Comparative Examples 5 to 8

A lithium battery was prepared in the same manner as in Example 7 except that the organic electrolytes prepared in Comparative Examples 1 to 4 were used in place of the organic electrolytes prepared in Example 1, respectively.

Evaluation Example 1: Evaluation of room temperature impedance

The lithium batteries prepared in Examples 7 to 12 and Comparative Examples 5 to 8 were charged to a voltage of 50% of the state of charge (SOC) at a current of 0.5 C in the first cycle, cut off at 0.02 C, and then passed through an impedance analyzer Material Mates 7260 impedance analyzer) was used to measure the impedance by a two-probe method. The frequency range for the impedance measurement was 0.1 Hz to 10 MHz. A Nyquist plot for a portion of the impedance measurement results is shown in FIG.

As shown in FIG. 1, the lithium batteries of Examples 7 and 10 had a lower resistance than the lithium battery of Comparative Example 6. In particular, the lithium batteries of Examples 7 and 10 exhibited lower resistance than the lithium battery of Comparative Example 5 which did not contain additives.

Evaluation Example 2: Evaluation of high rate characteristics

The lithium batteries prepared in Examples 7 to 9 and Comparative Examples 5 to 7 were charged at a constant current of 0.1 C rate in a voltage range of 2.8 to 4.3 V relative to lithium metal at room temperature and discharged at a current density The dose was measured. The current densities at discharge were 0.2C, 0.5C, 1C and 2C rates, respectively. The discharge capacity at 1C is assumed to be 100%, and the relative discharge capacity at 2C is calculated by the following Equation 1 and is shown in Table 1 below.

&Quot; (1) &quot;

2C Relative discharge capacity [%] = [2C discharge capacity / 1C discharge capacity] x 100

1C discharge capacity
[%] 2C Relative discharge capacity
[%] Example 7 100 93.08 Example 8 100 93.47 Example 9 100 92.86 Comparative Example 5 100 84.86 Comparative Example 6 100 87.08 Comparative Example 7 100 91.00

As shown in Table 1, the lithium batteries of Examples 7 to 9 had a relatively smaller discharge capacity at a high rate than the lithium batteries of Comparative Examples 5 to 7. Therefore, the high rate characteristics were improved.

Evaluation Example 3: Evaluation of charging / discharging characteristics at normal temperature (25 캜)

The lithium battery prepared in Example 7 and Comparative Examples 5 and 7 was charged at a constant current of 0.1 C rate at 25 DEG C until the voltage reached 4.3 V (vs. Li), and then 4.3 V was maintained in the constant voltage mode And cut off at a current of 0.05 C rate. Then, the discharge was performed at a constant current of 0.1 C rate until the voltage reached 2.8 V (vs. Li) during the discharge (Mars phase, 1 ^st cycle).

The lithium battery having passed through the 1 ^st cycle of the above-described conversion step was charged at a constant current of 0.2 C at a current of 25 C until the voltage reached 4.3 V (vs. Li), and then maintained at 4.3 C Lt; RTI ID = 0.0 &gt; of &lt; / RTI &gt; Subsequently, discharge was performed at a constant current of 0.2 C rate until the voltage reached 2.8 V (vs. Li) (Mars phase, 2nd cycle).

The lithium battery having undergone the above conversion step was subjected to constant current charging at a current of 1.0 C rate at 25 DEG C until the voltage reached 4.3 V (vs. Li). Subsequently, the cycle of discharging at a constant current of 1.0 C rate until the voltage reached 2.8 V (vs. Li) at discharge was repeated up to 120 ^th cycle.

A stopping time of 10 minutes was provided after one charge / discharge cycle in all of the above charge / discharge cycles.

Part of the above charge / discharge test results are shown in Table 2 and FIG. The capacity retention rate in the 120 ^th cycle is defined by the following equation (2).

&Quot; (2) &quot;

Capacity retention rate = [Discharge capacity in 120 ^th cycle / Discharge capacity in 1 ^st cycle] × 100

Capacity retention rate in 120 ^th cycle [%] Example 7 96.3 Comparative Example 5 93.8 Comparative Example 7 95.1

As shown in Table 2 and FIG. 2, the lithium battery of Example 7 including the organic electrolyte of the present invention had better life characteristics at room temperature than the lithium batteries of Comparative Examples 5 and 7.

Evaluation Example 4: Evaluation of charging / discharging characteristics at high temperature (45 캜)

Charge-discharge characteristics of the lithium batteries prepared in Example 7 and Comparative Examples 5 and 7 were evaluated in the same manner as in Evaluation Example 1, except that the charge and discharge temperature was changed to 45 캜. Some of the evaluation results are shown in Table 3 and FIG.

Capacity retention rate in 120 ^th cycle [%] Example 7 93.5 Comparative Example 5 92.5 Comparative Example 7 93.6

As shown in Table 3 and FIG. 3, the lithium battery of Example 7 including the organic electrolytic solution of the present invention had better life characteristics at high temperature than the lithium batteries of Comparative Examples 5 and 7.

Evaluation Example 5: Evaluation of charging / discharging characteristics at room temperature (25 DEG C) (VC added)

The lithium batteries prepared in Examples 11 to 12 and Comparative Example 8 were subjected to constant current charging at a current of 0.1 C rate at 25 DEG C until the voltage reached 4.3 V (vs. Li), and then 4.3 V in the constant voltage mode And cut off at a current of 0.05 C rate. Then, the discharge was performed at a constant current of 0.1 C rate until the voltage reached 2.8 V (vs. Li) during the discharge (Mars phase, 1 ^st cycle).

The lithium battery having passed through the 1 ^st cycle of the above-described chemical conversion step was charged at a constant current of 0.2 C at a temperature of 25 ° C. until the voltage reached 4.3 V (vs. Li), and then maintained at 4.3 V rate cut-off. &lt; / RTI &gt; Subsequently, discharge was performed at a constant current of 0.2 C rate until the voltage reached 2.8 V (vs. Li) (Mars phase, 2nd cycle).

The lithium battery having undergone the above conversion step was subjected to constant current charging at a current of 1.0 C rate at 25 DEG C until the voltage reached 4.3 V (vs. Li). The cycle of discharging at a constant current of 1.0 C rate until the voltage reached 2.8 V (vs. Li) at discharge was repeated up to 300 ^th cycle.

A stopping time of 10 minutes was provided after one charge / discharge cycle in all of the above charge / discharge cycles.

Part of the charge-discharge test results are shown in Table 4 and FIG. The capacity retention rate in the 300 ^th cycle is defined by the following equation (3).

&Quot; (3) &quot;

Capacity retention rate = [Discharge capacity in 300 ^th cycle / Discharge capacity in 1 ^st cycle] × 100

Capacity retention rate in 300 ^th cycle [%] Example 11 82.4 Example 12 79.8 Comparative Example 8 77.8

As shown in Table 4 and FIG. 4, the lithium batteries of Examples 11 to 12 including the organic electrolytic solution of the present invention had better life characteristics at room temperature than the lithium batteries of Comparative Example 8.

Evaluation Example 6: Evaluation of charging / discharging characteristics at high temperature (45 캜) (VC added)

Charge-discharge characteristics of the lithium batteries of Examples 11 to 12 and Comparative Example 8 were evaluated in the same manner as in Evaluation Example 5, except that the charge and discharge temperature was changed to 45 캜. Part of the evaluation results are shown in Table 5 and Fig.

Capacity retention rate in 120 ^th cycle [%] Example 11 82.3 Example 12 79.0 Comparative Example 8 75.1

As shown in Table 5 and FIG. 5, the lithium battery of Examples 11 to 12 including the organic electrolytic solution of the present invention had improved lifetime characteristics at high temperature as compared with the lithium battery of Comparative Example 8.

Evaluation Example 7: Evaluation of High Temperature Stability at 60 캜

The lithium battery produced in Example 11 and Comparative Example 8 was subjected to a heat treatment at room temperature (25 占 폚)

In the 1st cycle, the battery was charged to 4.3V at a rate of 0.5C, then charged at a constant voltage until the current reached 0.05C while maintaining the voltage at 4.3V, and discharged at a rate of 0.5C to a constant current of 2.8V.

The 2 ^nd cycle was charged to 4.3 V at a speed of 0.5 C, then charged at a constant voltage until the current became 0.05 C while maintaining the voltage at 4.3 V, and discharged at a rate of 0.2 C to a constant current of 2.8 V.

The 3 ^rd cycle was charged to 4.3 V at a speed of 0.5 C and then charged at a constant voltage until the current reached 0.05 C while maintaining the voltage at 4.3 V and discharged at a constant current of 2.80 V at a rate of 0.2C. The discharge capacity in the 3 ^rd cycle was regarded as a standard capacity.

After charging to 4.30 V at a speed of 0.5 C in the fourth cycle and then constantly charging the battery at a current of 0.05 C while maintaining the voltage at 4.30 V, the charged battery was charged into a 60 ° C. oven at 10, 30, , The battery was taken out, and a discharge of 4th cycle was carried out at a rate of 0.1 C to 2.80 V.

The charge and discharge evaluation results are shown in Table 6 and FIG. The capacity retention after storage at high temperature is defined by the following equation (4).

&Quot; (4) &quot;

(%) = [Discharge capacity after leaving at a high temperature in the 4th cycle / standard capacity] × 100 (the standard capacity is the discharge capacity in 3 ^rd cycle)

Example 11 Comparative Example 8 Capacity retention rate after 10 days storage [%] 97.2 93.5 Capacity retention rate after 30 days storage [%] 94.0 91.0 Capacity retention rate after 60 days storage [%] 90.3 87.1

As shown in Table 6 and FIG. 6, the lithium battery of Example 11 including the organic electrolytic solution of the present invention showed a remarkable increase in stability at high temperature as compared with the lithium battery of Comparative Example 8 containing no organic electrolytic solution of the present invention.

Evaluation Example 8: Evaluation of DC Resistance (DC-IR) after High Temperature Storage at 60 캜

The lithium batteries prepared in Example 11 and Comparative Example 8 were stored in an oven at 60 ° C. for 10 days, 30 days, and 60 days, and the battery was taken out and the DC resistance (DC-IR) was measured by the following method.

In the first cycle, the battery was charged at a current of 0.5 C to a state-of-charge (SOC) voltage of 100%, cut off at 0.02 C,

0.5 C for 30 seconds, then 30 seconds of rest, 30 seconds of constant current charge at 0.5 C,

1.0 C for 30 seconds, then stopped for 30 seconds, charged at 0.5 C for 1 minute with a constant current, stopped for 10 minutes,

2.0 C for 30 seconds, then stopped for 30 seconds, charged at 0.5 C for 2 minutes with a constant current, stopped for 10 minutes,

3.0C for 30 seconds, and then stopped for 30 seconds. Then, the battery was charged at 0.5 C for 3 minutes with a constant current and stopped for 10 minutes.

From the average voltage drop value for 10 seconds for each C-rate, the DC resistance value is obtained by? V =? IR.

The measured initial DC resistance and the DC resistance increase rate calculated from the DC resistance after high temperature storage are shown in Table 7 and FIG. The DC resistance increase rate is expressed by the following equation (5).

Equation (5)

DC resistance increase rate [%] = [DC resistance after high temperature storage / initial DC resistance] × 100

Example 11 Comparative Example 8 DC resistance increase rate after 10 days storage [%] 105.3 104.8 DC resistance increase rate after 30 days storage [%] 113.5 113.1 DC resistance increase rate after 60 days storage [%] 117.5 120.8

As shown in Table 7 and FIG. 7, the lithium battery of Example 11 including the organic electrolytic solution of the present invention had a higher increase rate of DC resistance after storage at high temperature than the lithium battery of Comparative Example 8 which did not include the organic electrolytic solution of the present invention Respectively. Thus, the output characteristics can be improved.

Claims (13)

An additive for a lithium battery electrolyte which is a phosphorous base compound represented by the following formula (1)
&Lt; Formula 1 >

In this formula,
R ₁ and R ₂ are independently of each other halogen; An alkyl group having 1 to 5 carbon atoms which is unsubstituted or substituted with halogen; An alkoxy group having 1 to 5 carbon atoms which is substituted or unsubstituted with halogen; A cycloalkyl group having 4 to 10 carbon atoms which is substituted or unsubstituted with halogen; An aryl group having 5 to 10 carbon atoms which is unsubstituted or substituted with halogen; A heteroaryl group having 2 to 10 carbon atoms which is unsubstituted or substituted with halogen; An alkenyl group having 2 to 5 carbon atoms which is substituted or unsubstituted with halogen; Or an alkynyl group having 2 to 5 carbon atoms which is substituted or unsubstituted with halogen,
Provided that at least one of R ₁ and R ₂ is an alkyl group or an alkoxy group,
R ₁ and R ₂ may combine with each other to form a ring. The phosphor according to claim 1, wherein the phosphorus compound represented by Formula 1 is a phosphinate-based compound represented by Formula 2, a phosphate-based compound represented by Formula 3, or a phosphor represented by Formula 4 Additives that are phosphonate compounds:
&Lt; Formula 2 >< EMI ID =

In this formula,
R ₃ and R ₄ independently of one another are halogen; An alkyl group having 1 to 5 carbon atoms which is unsubstituted or substituted with halogen; A cycloalkyl group having 4 to 10 carbon atoms which is substituted or unsubstituted with halogen; An aryl group having 5 to 10 carbon atoms which is unsubstituted or substituted with halogen; A heteroaryl group having 2 to 10 carbon atoms which is unsubstituted or substituted with halogen; An alkenyl group having 2 to 5 carbon atoms which is substituted or unsubstituted with halogen; Or an alkynyl group having 2 to 5 carbon atoms which is substituted or unsubstituted with halogen,
Provided that at least one of R ₃ and R ₄ is an alkyl group or an alkoxy group,
R ₃ and R ₄ may combine with each other to form a ring. The phosphorous compound according to claim 1, wherein the phosphorus compound represented by Formula 1 is a phosphinate-based compound represented by Formula 5, a phosphate-based compound represented by Formula 6, or a phosphor represented by Formula 7: Additives that are phosphonate compounds:
&Lt; Formula 5 >< EMI ID =

In this formula,
R ₅ and R ₆ independently of one another are halogen; An alkyl group having 1 to 5 carbon atoms which is substituted or unsubstituted with halogen,
Provided that at least one of R ₅ and R ₆ is an alkyl group,
R ₅ and R ₆ may combine with each other to form a ring. The method of claim 1, wherein R ₁ and R ₂ are independently selected from the group consisting of F, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert- butyl, pentyl, Propoxy group, isopropoxy group, butoxy group, isobutoxy group, tert-butoxy group or pentoxy group. 2. The phosphor according to claim 1, wherein the phosphorus compound represented by the formula (1)
&Lt; Formula 8 >< EMI ID =

&Lt; Formula 11 &gt;&lt; EMI ID =

&Lt; Formula 14 >< EMI ID =

&Lt; Formula 17 &gt;&lt; EMI ID = 18.0 &gt;

&Lt; Formula 20 &gt;&lt; EMI ID =

&Lt; Formula 23 >< EMI ID =

A first lithium salt as an additive according to any one of claims 1 to 5;
A second lithium salt; And
An organic electrolytic solution comprising an organic solvent. The organic electrolytic solution according to claim 6, wherein the content of the first lithium salt is 0.01 to 5% by weight based on the total weight of the organic electrolytic solution. The organic electrolytic solution according to claim 6, further comprising a cyclic carbonate-based compound containing a non-polar unsaturated group. The method of claim 8, wherein the non-polar unsaturated group-containing cyclic carbonate compound is vinylene carbonate (VC); Vinylene carbonate substituted with at least one substituent selected from halogen, cyano group (CN) and nitro group (NO ₂ ); Vinyl ethylene carbonate (VEC); And vinylethylene carbonate substituted with at least one substituent selected from halogen, cyano group (CN) and nitro group (NO ₂ ); &Lt; / RTI &gt; The organic electrolytic solution according to claim 8, wherein the content of the non-polar unsaturated group-containing cyclic carbonate compound is 0.01 to 5% by weight based on the total weight of the organic electrolytic solution. The lithium secondary battery according to claim 6, wherein the second lithium salt is LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , LiAlO ₂ , LiAlCl ₄ , LiN (C _x F _{2x + 1} SO ₂ ) (C _y F _{2y + 1} SO ₂ ) (x and y are each an integer of 1 to 20), LiCl, LiI, . The method of claim 6, wherein the organic solvent is selected from the group consisting of ethyl methyl carbonate (EMC), methyl propyl carbonate, ethyl propyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, propylene carbonate (EC), fluoroethylene carbonate (FEC), butylene carbonate, ethyl propionate, ethyl butyrate, acetonitrile, succinonitrile (SN), dimethyl sulfoxide, dimethyl formamide, dimethylacetamide, An organic electrolytic solution comprising at least one selected from the group consisting of lactone, gamma-butyrolactone, and tetrahydrofuran. anode; cathode; And
A lithium battery comprising the organic electrolytic solution according to claim 6.

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