WO2016122277A1

WO2016122277A1 - Positive active material for lithium secondary battery, method for producing same, and lithium secondary battery comprising same

Info

Publication number: WO2016122277A1
Application number: PCT/KR2016/001073
Authority: WO
Inventors: 최수안; 정호준; 전상훈; 양지운; 신준호; 정진성; 정봉준
Original assignee: 주식회사 엘앤에프
Priority date: 2015-01-30
Filing date: 2016-02-01
Publication date: 2016-08-04

Abstract

Provided is a positive active material for a lithium secondary battery, the material being a compound capable of reversible intercalation and deintercalation of lithium and represented by chemical formula 1: [chemical formula 1] Li_aM₁-_bM'_bO_2, wherein metal M is at least one element selected from the group consisting of Ni, Co, and Mn; M' is at least one element selected from the group consisting of Zr, Ti, Mg, Ca, V, Zn, W, Mo, Sn, Ga, B, and Al; 0.90<a<1.10; and 0.09<b<0.15, the compound of chemical formula 1 comprising a coating layer positioned on at least a part of the surface thereof, wherein the coating layer comprises Li₃PO₄ and also comprises a composite coating layer further comprising lithium metal oxides, metal oxides, or a combination thereof.

Description

【Specification】

[Name of invention]

Cathode active material for lithium secondary battery, manufacturing method thereof and lithium secondary battery comprising same

Technical Field

It relates to a positive electrode active material for a lithium secondary battery, a manufacturing method thereof and a positive electrode active material for a lithium secondary battery.

Background Art

Recently, with the trend toward miniaturization and light weight of portable electronic devices, the need for high performance and high capacity of batteries used as power sources for these devices is increasing. A battery generates electric power by using an electrochemical reaction material for the positive electrode and the negative electrode. A typical example of such a battery is a lithium secondary battery that generates electrical energy by a change in chemical potent al when lithium ions are intercalated / deintercalated at a positive electrode and a negative electrode.

The lithium secondary battery is prepared by using a material capable of reversible intercalation / deintercalation of lithium ions as a positive electrode and a negative electrode active material, and layering an organic electrolyte or a polymer electrolyte between the positive electrode and the negative electrode. A lithium composite metal compound is used as a cathode active material of a lithium secondary battery, and composite metal oxides such as LiCo02, LiMn ₂ O _4> LiNi0 ₂ , and LiMn0 ₂ have been studied. Among the cathode active materials, Mn-based cathode active materials such as LiMn ₂ 0 ₄ and LiMn0 ₂ are easy to synthesize, are relatively inexpensive, have the best thermal stability compared to other active materials when overcharged, and have low environmental pollution and are attractive materials. Although it has a disadvantage, the capacity is small.

LiCo0 ₂ has a good electrical conductivity and a high battery voltage of about 3.7V, and also has excellent cycle life characteristics, stability, and discharge capacity. Thus, LiCo0 ₂ is a representative cathode active material commercially available and commercially available. However, since LiCo0 ₂ is expensive, it takes up more than 30% of the battery price, which leads to a problem of low price competitiveness.

In addition, LiNi0 ₂ exhibits the highest discharge capacity of battery characteristics among the cathode active materials mentioned above, but has a disadvantage in that it is difficult to synthesize. Also high of nickel The oxidized state causes deterioration of battery and electrode life, and causes severe self discharge and inferior reversibility. In addition, it is difficult to commercialize the stability is not perfect.

As described above, a cathode active material for a lithium secondary battery including various coating layers for improving battery characteristics has been provided.

[Content of invention]

[Problem to solve]

The present invention provides a cathode active material for a lithium secondary battery having excellent high capacity, high efficiency, and lifespan, and provides a lithium secondary battery including a cathode including the cathode active material.

[Measures of problem]

In one embodiment of the present invention, in a compound capable of reversible intercalation and deintercalation of lithium,

The compound is represented by the following formula (1),

[Formula 1]

Li _a Mi— _b M ᅳ _b 0 ₂

In Chemical Formula 1,

The metal M is at least one element selected from the group consisting of Ni, Co and Mn and M, is a group consisting of Zr ', Ti, Mg, Ca, V, Zn, W, Mo, Sn, Ga, B, and Al. At least one element selected from 0.90 <a <1.10, 0.09 <b <0.15,

It includes a coating layer located on at least a portion of the surface of the compound of Formula 1,

The coating layer includes Li ₃ P0 ₄ , and the coating layer provides a cathode active material for a lithium secondary battery comprising a composite coating layer further comprising lithium metal oxide, metal oxide, or a combination thereof.

In Chemical Formula 1,

The metal M 、 may be at least one element selected from Mg, Ti, Zr, Al, and B. In Chemical Formula 1, The metal can be.

Compounds capable of reversible intercalation and deintercalation of lithium

Li r i ch (Li / M rat i o> 1.0) composition.

Li ₃ PO ₄ included in the composite coating layer, or lithium of lithium metal oxide is derived from Li contained in the compound capable of reversible intercalation and deintercalation of the lithium, or from a separate Li supply material Can be.

The metal in the lithium metal oxide, or metal oxide contained in the composite coating layer may be Na, K, Ca, Ni, Co, Ti, Al, Si, Sn, Mn, Cr, Fe, V, Zr, or a combination thereof. have.

The content of the composite coating layer relative to the total weight of the cathode active material is 0.2 to

Can be 2.0% by weight

In another embodiment of the present invention, a dry mixing of a lithium feed material, a transition metal precursor, and a “feed material;

Firing the mixture; And

Obtaining a compound represented by Formula 1;

Preparing a compound capable of reversible intercalation and deintercalation of lithium represented by Formula 1;

Phosphorus source; And preparing a metal source;

The phosphorus source in a compound capable of reversible intercalation and deintercalation of lithium; And / or mixing a metal source to uniformly attach the phosphorus source to a surface of the compound capable of reversible intercalation and deintercalation of lithium; And

The phosphorus source; Or heat-treating a compound capable of reversible intercalation and deintercalation of lithium to which a metal source is attached, including Li ₃ P0 ₄ , wherein the coating layer further comprises lithium metal oxide, metal oxide, or a combination thereof. It provides a method for producing a cathode active material for a lithium secondary battery comprising the step; obtaining; a compound capable of reversible intercalation and deintercalation of lithium comprising a composite coating layer. ^'

[Formula 1]

Li _a Mi- _b M 0 ₂ In Chemical Formula 1,

Metal M is at least one element selected from the group consisting of Ni, Co and Mn and M, is selected from the group consisting of Zr, Ti, Mg, Ca, V, Zn, W, Mo, Sn, Ga, B, and Al At least one element, and 0.90 <a <1.10, 0.09 <b <0.15.

In the step of firing the mixture; the firing temperature may be 750 to 1,050 ^° C.

The phosphorus source; And / or heat treating a compound capable of reversible intercalation and deintercalation of lithium to which a metal source is attached, wherein Li ₃ P0 ₄ is included, wherein the coating layer comprises lithium metal oxide, metal oxide, or a combination thereof. In the step of obtaining a compound capable of reversible intercalation and deintercalation of lithium comprising a composite coating layer further comprising; in the heat treatment temperature, may be 650 to 950 ^° C. In another embodiment of the present invention, a positive electrode including a positive active material for a lithium secondary battery according to an embodiment of the present invention described above; A negative electrode including a negative electrode active material; And it provides an lithium secondary battery comprising an electrolyte.

【Effects of the Invention】

It is possible to provide a cathode active material having excellent battery characteristics and a lithium secondary battery including the same.

[Brief Description of Drawings]

1 is a schematic view of a lithium secondary battery. ^.

[Specific contents to carry out invention]

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, whereby the present invention is not limited and the present invention is defined only by the scope of the claims to be described later. In one embodiment of the present invention, in a compound capable of reversible intercalation and deintercalation of lithium, The compound is represented by the following formula (1),

[Formula 1] In Formula 1,

The metal M is at least one element selected from the group consisting of Ni, Co and Mn and M, is at least one selected from the group consisting of Zr, Ti, Mg, Ca, V, Zn, W, Mo, Sn, and Al. Elemental element, 0.90 <a <1.10, 0.09 <b <0.15

The coating layer includes Li ₃ PO ₄ and the coating layer provides a cathode active material for a lithium secondary battery comprising a composite coating layer further comprising a lithium metal oxide, a metal oxide, or a combination thereof.

In Chemical Formula 1,

The metal may be at least one element selected from Mg, Ti, Zr, Al, and B. In Chemical Formula 1,

The metal M 、 may be Mg. ...

In the case of excessive doping in a typical cathode active material, capacity degradation and battery characteristics may deteriorate. However, at a high voltage, due to the excessive doping, the structure is stabilized to provide a cathode active material suitable for high voltage.

In addition, when the metal M, Mg, Co4 + elution is suppressed at high voltage, thereby suppressing deterioration of battery characteristics.

The compound capable of reversible intercalation and deintercalation of lithium may be Li rich (Li / M ratio> 1.0) composition.

Li 3 P04 included in the composite coating layer, or lithium of lithium metal oxide may be derived from Li contained in the compound capable of reversible intercalation and deintercalation of the lithium, or may be derived from a separate Li supply material. .

The content of the composite coating layer relative to the total weight of the positive electrode active material is 0.2 to Can be 2.0% by weight

And said Li ₃ P0 ₄ . Lithium metal oxide,. A positive electrode active material including a composite coating layer further comprising a metal oxide or a combination thereof may improve battery characteristics of a lithium secondary battery. More specifically, it is possible to provide a cathode active material having a higher initial capacity, improved efficiency characteristics and excellent rate characteristics than conventional cathode active materials.

The metal compound including Li of the composite coating layer may serve to increase the diffusion degree of Li ions in the cathode active material to facilitate the movement of Li ions, thereby contributing to improvement of battery characteristics.

The above reversible intercalation and deintercalation compound of lithium may be particularly preferable for implementing battery characteristics by the coating layer if the specific doping element is excessively doped. In the LiM0 ₂ (M is Ni, Co, or Mn) composition system, rock-salt structures can be formed on the surface of the anode material under the usual manufacturing conditions. In the chemical reaction process in which U3P04 is formed as in the present invention. The rearrangement reaction (Rocksal t >> layered) occurs to control the structural defects and impurities formed on the surface. The general LiM0 ₂ (M is Ni, Co, or Mn) when applying the composition Li ₃ P0 ₄ is subject to the process is the Li shortage occurs battery characteristics, some degradation in the formed and also Li ₃ in the composition that is not doped When the P0 ₄ coating is carried out, structural defects may be caused by the reduction reaction generated between P and the surface of the cathode material. In conclusion, Li ₃ P0 ₄ is applied when the coating treatment is applied to a compound having a composition of Li r ich (Li / M rat io> 1.0) and capable of reversible intercalation and deintercalation of a lithium that is excessively doped with a specific element. It is possible to further provide a surface that can maximize the effect of the coating layer by suppressing the surface defects due to the lack of Li and the reduction reaction occurring during the formation. In another embodiment of the invention, dry mixing a lithium feed material, a transition metal precursor, and an NT feed material;

Firing the mixture; And

Obtaining a compound represented by Formula 1;

Reversible intercalation of lithium, represented by formula (1) Preparing a compound capable of deintercalation;

Phosphorus source; And / or preparing a metal source;

The phosphorus source in a compound capable of reversible intercalation and deintercalation of lithium; And / or a phosphorus source on the surface of a compound capable of combining a metal source to enable reversible intercalation and deintercalation of the lithium; And / or attaching the metal source uniformly; And

The phosphorus source; And / or heat-treating a compound capable of reversible intercalation and deintercalation of lithium to which a metal source is attached, comprising Li ₃ P0 ₄ , wherein the coating layer further comprises lithium metal oxide, metal oxide, or a combination thereof. It provides a method for producing a positive electrode active material for a lithium secondary battery comprising the step; obtaining; a compound capable of reversible intercalation and deintercalation of lithium comprising a composite coating layer comprising.

[Formula 1]

Li _a Mi-bM ^~ _b 0 ₂ ... _. In Chemical Formula 1,

Metal M is at least one element selected from the group consisting of Ni, Co and Mn and M, is selected from the group consisting of Zr, Ti, Mg, Ca, V, Zn, W, Mo, Sn, Ga, B, and Al At least one element, and 0.90 <a <L10 and 0.09 <b <0.15.

Calcining the mixture;

The firing temperature may be between 750 and 1,050 ^° C.

The phosphorus source; Or heat-treating a compound capable of reversible intercalation and deintercalation of lithium with a metal source attached thereto, comprising U3P04, wherein the coating layer comprises _: Obtaining a compound capable of reversible intercalation and deintercalation of lithium, including a composite coating layer further comprising lithium metal oxide, metal oxide, or a combination thereof;

The heat treatment temperature may be 650 to 95CTC. Description of the rest of the configuration is the same as the embodiment of the present invention described above, so the description thereof will be omitted. In another embodiment of the present invention, a lithium secondary battery comprising a positive electrode, a negative electrode and an electrolyte, the positive electrode includes a current collector and a positive electrode active material layer formed on the current collector, the positive electrode active material layer, It provides a lithium secondary battery comprising the positive electrode active material described above.

Descriptions related to the cathode active material are omitted because they are the same as the above-described embodiments of the present invention.

The positive electrode active material layer may include a binder and a conductive material.

The binder adheres positively to the positive electrode active material particles, and also serves to adhere the positive electrode active material to the current collector well, and representative examples thereof include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose and diacetyl cellulose. , Polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyridone, polyureth, polytetraple ^ oethylene, polyvinylidene fluoride, Polyethylene, polypropylene, styrene-butadiene rubber, acrylic styrene-butadiene rubber epoxy resin, nylon, etc. may be used, but is not limited thereto.

The conductive material is used to impart conductivity to the electrode, and any battery can be used as long as it is an electronic conductive material without causing chemical change in the battery. For example, natural alum, artificial alum, carbon black, acetylene black, ketjen Carbon-based materials such as black and carbon fiber; Metal materials such as metal powder or metal fibers such as copper, nickel, aluminum and silver; Conductive polymers such as polyphenylene and derivatives; Or an electroconductive material containing these mixture can be used.

The negative electrode includes a current collector and a negative electrode active material layer formed on the current collector, and the negative electrode active material layer includes a negative electrode active material.

The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, a lithium metal, an alloy of lithium metal, a material capable of doping and undoping lithium, or a transition metal oxide. .

As a material capable of reversibly intercalating / deintercalating the lithium ions, a carbon-based negative electrode active material generally used in a lithium ion secondary battery may be used, and representative examples thereof include crystalline carbon, Amorphous carbon or these may be used together. Examples of the crystalline carbon are amorphous, plate, Graphite, such as flakes, spherical or fibrous natural or artificial agglomerates. Examples of the amorphous carbon include soft carbon (low temperature calcined carbon) or hard carbon, mesophase. Pitch carbide, calcined coke, and the like.

As the alloy of the lithium metal, lithium and Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr,

Alloys of metals selected from the group consisting of Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al and Sn can be used.

Examples of a material capable of doping and undoping lithium include Si, SiO _x (0 <x <2), and Si-Y alloys (wherein Y is an alkali metal, an alkaline earth metal, a Group 13 element, and a Group 14 element transition metal. Element selected from the group consisting of ash earth elements and combinations thereof, not Si), Sn, Sn0 ₂ , Sn-Y (Y is an alkali metal, alkaline earth metal, group 13 element, group 14 element, transition rapid, an element selected from rare earth elements and combinations thereof, Sn and the like are not), and may also use at least one common and Si0 ₂ were combined of them. As the element Y, Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, 0s, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti ,, Ge, P, As, Sb, Bi. S, Se, Te, Po, and combinations thereof.

Examples of the transition metal oxide include vanadium oxide, lithium vanadium oxide, and the like.

The negative electrode active material layer also includes a binder, and may optionally further include a conductive material.

The binder adheres the negative electrode active material particles to each other well, and also adheres the negative electrode active material to the current collector, and typical examples thereof include polyvinyl alcohol, carboxymethyl salose, hydroxypropyl cellulose, poly H, and the like. Nyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene Styrene ᅳ butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon and the like may be used, but is not limited thereto.

The conductive material is used to impart conductivity to the electrode, In the battery, any electronic conductive material can be used without causing chemical change, and examples thereof include carbon-based materials such as natural alum, artificial alum, carbon black, acetylene black, ketjen black, and carbon fiber; Metal materials such as metal powder or metal fibers such as copper, nickel and aluminum silver; Conductive polymers such as polyphenylene derivatives; Or an electroconductive material containing these mixture can be used.

The current collector may be selected from the group consisting of copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof. .

A 1 may be used as the current collector, but is not limited thereto. The negative electrode and the positive electrode are prepared by mixing an active material, a conductive material and a binder in a solvent to prepare an active material composition, and applying the composition to a current collector. Since such an electrode manufacturing method is well known in the art, detailed description thereof will be omitted. N-methylpyridone may be used as the solvent, but is not limited thereto.

The electrolyte contains a non-aqueous organic solvent and a lithium salt.

The non-aqueous organic solvent serves as a medium for transfer of silver involved in the electrochemical reaction of the battery.

As the non-aqueous organic solvent, a carbonate-based, ester-based, ether-based, ketone-based, alcohol-based, or aprotic solvent may be used. The carbonate-based solvent may be dimethyl carbonate (DMC) or diethyl carbonate ( DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc. The ester solvent may be methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, _γ -butyrolactone, decanoide. , Valerolactone, mevalonolactone (meva l ono l actone), caprolactone (capro lactone), and the like can be used. As the ether solvent, dibutyl ether, tetraglyme, diglyme, dimetheethane, 2—methyltetrahydrofuran, tetrahydrofuran, and the like may be used, and the ketone solvent may be cyclohexanone or the like. This can be used. In addition, ethyl alcohol, isopropyl alcohol, etc. may be used as the alcohol solvent, and as the aprotic solvent, R-CN (R is carbon number). Amides such as nitrile dimethylformamide such as a linear, branched or ring structure hydrocarbon group of 2 to 20, which may include a double bond aromatic ring or an ether bond), 1,3-dioxolane and the like ^■ Dioxolanes and sulfolanes can be used.

The non-aqueous organic solvent may be used alone or in combination of one or more, and the mixing ratio in the case of using one or more in combination may be appropriately adjusted according to the desired battery performance, which is widely understood by those skilled in the art. Can be.

In addition, in the case of the carbonate solvent, it is preferable to use cyclic carbonate and chain carbonate in combination. In this case, the cyclic carbonate and the chain carbonate may be mixed and used in a volume ratio of 1: 1 to 1: 9, so that the performance of the electrolyte may be excellent.

The non-aqueous organic solvent according to the embodiment of the present invention may further include an aromatic hydrocarbon organic solvent in the carbonate solvent. In this case, the carbonate-based solvent and the aromatic hydrocarbon-based organic solvent may be mixed in a volume ratio of 1: 1 to 30: 1. As the aromatic hydrocarbon organic solvent, an aromatic hydrocarbon compound of Formula 2 may be used.

[Formula 2]

(In Formula 2, to are each independently hydrogen, halogen, C1 to C10 alkyl group, haloalkyl group or a combination thereof.)

The aromatic hydrocarbon organic solvent is benzene, fluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene, 1,2,3-trifluorobenzene , 1,2,4-trifluorobenzene, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2 ， 4-trichlorobenzene, iodobenzene, 1,2-diodiodobenzene, 1,3-dioiobenzene, 1 ᅳ 4-dioiobenzene, 1,2,3-triiodobenzene, 1 ᅳ 2 , 4-triiodobenzene, toluene, fluorotoluene, 1,2-difluoroluene, 1,3-di Fluoroluene, 1,4'difluoroluene ᅳ 1,2,3-trifluoroluene, 1,2,4-trifluoroluene, chloroluene, 1,2-dachloroluene , 1,3-dichloroluene, 1,4-dichloroluene, 1,2,3-trichloroluene, 1,2,4-trichlorotoluene, iodoluene, 1,2 Odo Toluene, 1,3 ᅳ diaioluluene, 1,4-diaioluluene, 1,2,3-triiodoluene, 1,2,4-triiodoluene, xylene, and It is selected from the group consisting of these combinations.

The non-aqueous electrolyte may further include vinylene carbonate or an ethylene carbonate compound of Formula 3 to improve battery life.

[Formula 3]

(In Formula 3, R ₇ and ¾ are each independently hydrogen, halogen group-cyano group (CN), nitro group (Ν0 ₂ ) or C1 to C5 fluoroalkyl group, at least one of R ₇ and ¾ is halogen Group, cyano group (CN), nitro group (N0 ₂ ) or C1 to C5 fluoroalkyl group.)

Representative examples of the ethylene carbonate compound include difluoro ethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate or fluoroethylene carbonate. Etc. can be mentioned. If such life improving additives are used further, their amount can be adjusted accordingly.

The lithium salt is a substance that dissolves in an organic solvent and acts as a source of lithium ions in the battery to enable operation of a basic lithium secondary battery and to promote the movement of lithium ions between the positive electrode and the negative electrode. Representative examples of such lithium salts are LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF _{6 (} LiC ₄ F ₉ S0 _3l LiC10 ₄ , LiA10 ₂ , .LiAlCl ₄ , LiN (C _x F _{2x + 1} S0 ₂ ) (C _y F _{2y) +1} S0 ₂ ) (where x and y are natural numbers), LiCl, Li I and LiB (C ₂ 0 ₄ ) ₂ (lithium bis (oxalato) borate (LiBOB) One or more selected ones are included as supporting electrolytic salts. The concentration of salt is preferably used in the range of 0.01 to 2.0M. When the concentration of the lithium salt is included in the above range, since the electrolyte has an appropriate conductivity and viscosity, it may exhibit excellent electrolyte performance, and lithium ions may move effectively.

Depending on the type of lithium secondary battery, a separator may exist between the positive electrode and the negative electrode. As the separator, polyethylene, polypropylene, polyvinylidene fluoride or two or more multilayer films thereof may be used _. Of course, a mixed multilayer film such as polyethylene / polypropylene two-layer separator, polyethylene / polypropylene / polyethylene three-layer separator, polypropylene / polyethylene / polypropylene three-layer separator, and the like can be used.

Lithium secondary batteries may be classified into lithium ion batteries, lithium ion polymer batteries, and lithium polymer batteries according to the type of separator and electrolyte used, and may be classified into cylindrical, square, coin, and pouch types according to their type. It can be divided into bulk type and thin film type according to the size. The structure, structure, and manufacturing method of these batteries are well known in the art, and thus detailed descriptions thereof are omitted.

1 schematically shows a typical structure of a lithium secondary battery of the present invention. As shown in FIG. 1, the lithium secondary battery 1 includes a positive electrode 3, a negative electrode 2, and an electrolyte solution impregnated in a separator 4 existing between the positive electrode 3 and the negative electrode 2. The container 5 and the sealing member 6 which encloses the said battery container 5 are included. Hereinafter, examples and comparative examples of the present invention are described. However, the following examples are only examples of the present invention and the present invention is not limited to the following examples. Example

Example 1

After dry mixing the Co ₃ 0 ₄ , Li ₂ C0 ₃ and MgC0 ₃ mixtures, the mixture is heat treated with lOCXTC for 10 hours to obtain Li

A positive electrode active material was prepared as possible.

100 g of the prepared cathode active material and Zr (0H) ₄ powder. 0. 172 g of dry powder of Si0 ₂ powder 0.054g and (NH ₄ ) ₂ HP0 ₄ powder 0,387g to prepare a mixture in which the powder is attached to the surface of the positive electrode active material body and then the mixture to 800 ^° C. Heat treatment was performed for 6 hours to prepare a positive electrode active material. Example 2

After dry mixing the Co ₃ O ₄ , Li ₂ CO ₃ and Zr0 ₂ mixtures; The mixture was heat-treated with KXXTC for 10 hours to prepare a cathode active material such that Li nCoQ.gZnuOz.

100g of the prepared cathode active material and Zr (0H) ₄ powder 0.15g and Si0 ₂ powder 0.054g

0.387 g of (NH ₄ ) ₂ HP0 ₄ powder was dry mixed to prepare a mixture having the powder attached to the surface of the positive electrode active material body, and the mixture was heat-treated at 800 ^° C. for 6 hours to prepare a positive electrode active material. Example 3

Ni ₀ . ₆ Co ₀ . After dry mixing ₂ Mn _0.2 (0H) ₂ , Li ₂ CO ₃ and MgC0 ₃ mixtures, the mixture was heat treated at 800 ^° C. for 12 hours to obtain Li

A positive electrode active material was prepared as possible.

100 g of the prepared cathode active material, 0.172 g of Zr (0H) ₄ powder, 172 g of Si0 ₂ powder, and 0.054 g of (NH ₄ ) ₂ HP0 ₄ powder were mixed in a dry mixture, and the powder adhered to the surface of the cathode active material body. After the preparation, the mixture was heated ^at 650 ^° C. for 6 hours to prepare a cathode active material. Comparative example. One .

After dry mixing the C03O4 _, Li ₂ CO ₃ and MgC0 ₃ mixture, the mixture was heat-treated with KXXTC for 10 hours to prepare a cathode active material such that Lh.02coo.8Mgo.202.

100 g of the prepared cathode active material, 0.172 g of Zr (0H) ₄ powder, 172 g of Si0 ₂ powder, and 0.054 g of (NH ₄ ) ₂ HP0 ₄ powder were mixed in a dry mixture, and the powder adhered to the surface of the cathode active material body. After the preparation, the mixture was heat-treated at 800 ^° C. for 6 hours to prepare a cathode active material. Comparative Example 2

100 g of LiCo0 ₂ and Zr (0H) ₄ powder, 172 g, 0.054 g of Si0 ₂ powder and 0.387 g of (NH ₄ ) ₂ HP0 ₄ powder were dry mixed to prepare a mixture having the powder attached to the surface of the positive electrode active material body. After the mixture was heat-treated at 800 ^' C for 6 hours to prepare a cathode active material. Comparative Example 3

LiCo0 ₂ was used. Comparative Example .4

The LiNi ₀ .6oCoo.2oMno.2o0 ₂ was used. Production of coin cell

95% by weight of the positive electrode active material prepared in Examples and Comparative Examples, 2.5% by weight of carbon black as a conductive agent, 2.5% by weight of PVDF as a binder, N-methyl-2 pyridone (NMP) as a solvent (solvent) A positive electrode slurry was prepared by adding to 5.0 wt%. The positive electrode slurry was applied to a thin film of aluminum (A1), which is a positive electrode current collector having a thickness of 20 to 40, and vacuum dried, followed by roll press to prepare a positive electrode.

Li-metal was used as the negative electrode.

As a counter electrode and a Li-metal prepared as described above, a half cell of a coin sal type was manufactured using 1.15M LiPF ₆ EC: DMC (l: lvol¾) as an electrolyte.

Layer discharge was carried out in the range 4.5-3.0V. Experimental Example 1 Battery Characteristic Evaluation

Table 1 below is 4.5V initial Formation, rate characteristic, lcyle, 20cycle, 30cycle capacity and life characteristic data of the above Examples and Comparative Examples.

TABLE 1

Life Characteristics Life Characteristics

Discharge capacity 1CY 20CY 30CY

(mAh / g) a (medium at (20CY / (30CY /

Discharge Capacity Discharge Capacity (1.0 / 0.2C,%)

1CY,%) 1CY,%)

Example 1 192.47 97.79 186.10 181.13 177.23 97.33 95.23 96.66 Example 2 191.72 97.43 184.91 180.09 176.34 97.39 95.37 96.71 Example 3 202.47 91.07 196.22 183.74 180.11 93.64 91.79 91.14 Comparative Example 1184.92 95 9 292 195 295 195 295 195 295 179.14 174.12 96.25 93.55 95.61 Comparative Example 3 189.74 95.11 185.22 160.81 147.54 86.82 79.66 92.81 Comparative Example 4 20 1 1 87.91 1 95.68 1 77.54 1 66. 1 7 90.73 84.92 88.89

In Table 1, Examples 1 to 3 are confirmed battery characteristics superior to Comparative Examples 1 to 4.

In Examples 1 to 2, the positive electrode active material including the excessively doped composite coating layer includes the composite coating layer, but Comparative Example 2, which is not doped, is confirmed to have a difference in battery characteristics. Excess doping is found to be useful for high voltages.

Excessive doping was found to be less effective in battery characteristics compared to Comparative Example 1, which is more heavily doped.

In addition, the positive electrode active material having a different composition is also confirmed to improve characteristics.

The present invention is not limited to the above embodiments, but may be manufactured in various forms, and a person of ordinary skill in the art to which the present invention pertains does not change the technical spirit or essential features of the present invention. It will be appreciated that the present invention may be practiced as. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Claims

【Patent Claims】【Claim 1】 In the compound capable of reversible intercalation and deintercalation of lithium, the compound is represented by the following formula 1,

[Formula 1]

Li _a Mi-bM ^' _b 0 ₂

In Formula 1,

Metal M is at least one element selected from the group consisting of Ni, Co, and Mn, and Mᅳ is from the group consisting of Zr, Ti, Mg, Ca, V, Zn, W, Mo, Sn, Ga, B, and Al. At least one element is selected, and 0.90<a<1.10, 0.09<b<0.15,

Compound of Formula 1. It includes a coating layer located on at least a portion of the surface of the compound,

The coating layer includes Li ₃ P0 ₄ , and the coating layer includes a composite coating layer further including lithium metal oxide, metal oxide, or a combination thereof.

[Claim 2]

In clause 1,

In Formula 1,

A cathode active material for a lithium secondary battery, wherein the metal M is at least one element selected from Mg, Ti, Zr, Al, and B.

[Claim 3]

In clause 1,

In Formula 1 above, .

A positive electrode active material for a lithium secondary battery, wherein the metal M ^' is Mg.

[Claim 4]

In clause 1,

Compounds capable of reversible intercalation and deintercalation of lithium are A positive electrode active material for lithium secondary batteries having a Li rich (Li/M ratio >1.0) composition.

【Claim 5】

In clause 1,

Li ₃ P0 ₄ contained in the composite coating layer, or lithium of lithium metal oxide, originates from Li contained in a compound capable of reversible intercalation and deintercalation of the lithium, or originates from a separate Li supply material. A positive electrode active material for lithium secondary batteries.

【Claim 6】

In paragraph 1,

In the lithium metal oxide or metal oxide contained in the composite coating layer, the metal is Na, K, Ca, Ni, Co, Ti, Al, Si, Sn, Mn, Cr, Fe, V, Zr, or a combination thereof. Cathode active material for phosphorus lithium secondary batteries.

【Claim 7】

In paragraph 1,

A positive electrode active material for a lithium secondary battery, wherein the content of the composite coating layer relative to the total weight of the positive electrode active material is 0.2 to 2.0% by weight.

【Claim 8】

Dry mixing the lithium supply material, transition metal precursor, and M ^' supply material; Calcining the mixture; and

Obtaining a compound represented by the following formula (1);

. do . Preparing a compound capable of reversible intercalation and deintercalation of lithium represented by Formula 1;

Phosphorus source; and/or preparing a metal source;

The phosphorus source is added to the compound capable of reversible intercalation and deintercalation of lithium; and/or a phosphorus source on the surface of the compound capable of reversible intercalation and deintercalation of lithium by combining a metal source; and/or uniformly attaching the metal source; and

the phosphorus source; and/or Li ₃ P0 ₄ by heat treating a compound capable of reversible intercalation and deintercalation of lithium to which a metal source is attached, and the coating layer further includes lithium metal oxide, metal oxide, or a combination thereof. Obtaining a compound capable of reversible intercalation and deintercalation of lithium including a composite coating layer;

Method for producing a positive electrode active material for a lithium secondary battery comprising:

[Formula 1]

(In Formula 1 above,

Metal M is at least one element selected from the group consisting of Ni, Co, and Mn, and is at least one element selected from the group consisting of Zr, Ti, Mg, Ca, V, Zn, ff, Mo, Sn, Ga, B, and Al. It is one element, 0.90<a<1.10, 0.09<b<0.15.)

【Claim 9】

In paragraph 8 _. Because,

In the step of calcining the mixture,

A method for producing a positive electrode active material for a lithium secondary battery, wherein the sintering temperature is 750 to 1,050 ^° C. _.

【Claim 10】

In paragraph 18,

the lithium source; phosphorus source; and/or heat-treating a compound capable of reversible intercalation and deintercalation of lithium to which a metal source is attached, including Li3P04, and the coating layer further includes lithium metal oxide, metal oxide, and/or a combination thereof. In the step of obtaining a compound capable of reversible intercalation and deintercalation of lithium comprising a composite coating layer comprising:

A method of producing a positive electrode active material for a lithium secondary battery, wherein the heat treatment temperature is 650 to 950 ^° C. 【Claim 11】

A positive electrode containing the positive electrode active material for a lithium secondary battery according to any one of claims U to 7; . _.

A negative electrode containing a negative electrode active material; and

electrolyte;

Lithium secondary battery containing.