CN106129328B - Positive active material - Google Patents

Positive active material Download PDF

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Publication number
CN106129328B
CN106129328B CN201610533779.2A CN201610533779A CN106129328B CN 106129328 B CN106129328 B CN 106129328B CN 201610533779 A CN201610533779 A CN 201610533779A CN 106129328 B CN106129328 B CN 106129328B
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lithium
ratio
active material
compound
transition metal
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CN106129328A (en
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森田耕诗
细谷洋介
藤木聪
本桥一成
李国华
远藤一显
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Murata Northeast China
Murata Manufacturing Co Ltd
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Murata Manufacturing Co Ltd
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Priority claimed from JP2010105024A external-priority patent/JP5589536B2/en
Priority claimed from JP2010105025A external-priority patent/JP5644176B2/en
Application filed by Murata Manufacturing Co Ltd filed Critical Murata Manufacturing Co Ltd
Priority claimed from CN201010279232.7A external-priority patent/CN102024950B/en
Publication of CN106129328A publication Critical patent/CN106129328A/en
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G51/00—Compounds of cobalt
    • C01G51/006—Compounds containing, besides cobalt, two or more other elements, with the exception of oxygen or hydrogen
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G51/00—Compounds of cobalt
    • C01G51/40—Cobaltates
    • C01G51/42—Cobaltates containing alkali metals, e.g. LiCoO2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H01M4/1315—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx containing halogen atoms, e.g. LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/50—Solid solutions
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/50—Solid solutions
    • C01P2002/52—Solid solutions containing elements as dopants
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/20—Particle morphology extending in two dimensions, e.g. plate-like
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/54—Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/40—Electric properties
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Chemical Kinetics & Catalysis (AREA)
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  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Inorganic Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

The present invention provides a kind of positive active materials, including lithium-compound transition metal oxide, lithium-the compound transition metal oxide includes lithium, primary transition metal M1 and metallic element M2 different from primary transition metal M1, wherein metallic element M2 has the concentration gradient of the metallic element M2 from from the center of each particle to surface, in the range of the ratio d (%) from surface to certain depth meets 0.020≤d≤0.050, molar fraction r (%) meets formula 0.20≤r≤0.80, wherein, ratio d (%)=[(quality of the primary transition metal M1)+(quality of metallic element M2)]/(quality of particle entirety), molar fraction r=(amount of substance of metallic element M2)/[(amount of substance of primary transition metal M1)+(gold Belong to the amount of substance of element M 2)], wherein primary transition metal M1 is selected from least one of nickel, cobalt, manganese and iron, and metallic element M2 is selected from least one of manganese, magnesium, aluminium, nickel, boron, titanium, cobalt and iron element.

Description

Positive active material
The application be the applying date be September in 2010 9, application No. is 201410014566.X, it is entitled that " anode is living The divisional application of property substance ", and application No. is the application of 201410014566.X be in September, 2010 applying date 9, application number For 201010279232.7, entitled " positive active material and preparation method thereof, anode and nonaqueous electrolyte battery " The divisional application of application for a patent for invention.
Technical field
The present invention relates to a kind of positive active material, anode, nonaqueous electrolyte battery and prepare positive active material Method.More particularly it relates to which one kind, which can be realized when charging and discharging in the high temperature environment by it, to be had High-performance and present the positive active material of nonaqueous electrolyte battery, anode, nonaqueous electrolyte battery of very little capacity deterioration with And the method for preparing positive active material.In particular it relates to a kind of including lithium-compound transition metal oxide anode Active material.
Background technique
In recent years, with portable device, such as video camera and notebook personal computer are popularized, to small-sized Gao Rong The demand of amount secondary cell and battery increasingly increases.Secondary cell used at present includes the nickel-using alkaline electrolyte Cadmium cell and nickel-hydrogen cell.However, the shortcomings that these secondary cells, is cell voltage down to about 1.2V and is difficult to improve energy Metric density.Therefore, voltage is higher than other battery systems and nowadays the higher lithium ion secondary battery of energy density has obtained extensively General utilization.
However, due to charging voltage with higher compared with other battery systems, lithium ion secondary battery is asked Topic is, when in a manner of being maintained for a long time in the charge state in use, the longevity that its capacity can be deteriorated and its is useful Life can be shortened.In addition, the raising of internal resistance can be generated when using lithium ion secondary battery under high ambient conditions, So that it is very difficult to ensure enough capacity.The scheme for needing to solve these problems strongly.
LiCoO2、LiNiO2It is widely used as lithium ion secondary battery with other lithiums-compound transition metal oxide particle Positive active material.Recently, it has been proposed that by forming coat at the surface of the particles or making some materials from particle surface Diffusion is to improve the state of particle surface to obtain the various technologies of the more preferable performance of lithium-compound transition metal oxide particle.
For example, showing metal salt or hydrogen in Japanese Patent No. 3197763 (hereinafter, referred to as patent document 1) Oxide is added to the method in anode.In addition, (hereinafter, referred to as patent is literary by Japanese Patent Publication Hei 5-47383 It offers and 2) shows a kind of phosphorus (P) coating cobalt acid lithium (LiCoO2) surface technology.Japanese Patent No. 3172388 (under Wen Zhong, referred to as patent document 3) and Japanese Patent No. 3691279 (hereinafter, referred to as patent document 4) show a kind of use The method on the surface of metal oxide-coated positive active material or anode.
Japanese Patent Publication Hei 7-235292 (hereinafter, referred to as patent document 5), Japanese Patent Publication No. 2000-149950 (hereinafter, referred to as patent document 6), (hereinafter, the title of Japanese Patent Publication the 2000-156227th Make patent document 7), Japanese Patent Publication No. 2000-164214 (hereinafter, referred to as patent document 8), Japanese Patent Publication No. 2000-195517 (hereinafter, referred to as patent document 9), Japanese Patent Publication the 2001-196063rd (hereinafter, Referred to as patent document 10), Japanese Patent Publication No. 2002-231227 (hereinafter, referred to as patent document 11) etc. shows Wherein with lithium-compound transition metal oxide be evenly coated with particle surface method and wherein composite oxides from particle Diffusion into the surface method.In addition, Japanese Patent Publication the 2001-256979th (hereinafter, referred to as patent document 12) is shown The block for having gone out wherein metal oxide is deposited on positive active material on metal oxide layer.Japanese Patent Publication 2002- No. 164053 (hereinafter, referred to as patent document 13) are shown in which that on the surface of the core comprising lithium compound, formation includes The positive active material of at least one surface-treated layer of at least two coating elements.
Japanese Patent Publication the 3157413rd (hereinafter, referred to as patent document 14) discloses one kind wherein in particle Surface on setting include metal fluoride coating positive active material, and Japanese Patent Publication the 3141858th ( Hereinafter referred to as patent document 15) show a kind of coating including crystal metal fluoride.In addition, Japanese Patent Publication No. 2003-221235 XPS (x-ray photoelectron spectroscopy) energy described to fluorine on the surface of particle provides.When this The inventor of invention prepares positive work by the method for mixed metal fluoride and thermally treated mixture according to the disclosure When property substance, observe the actual effect about high temperature dwell sustainability, but the effect be limited to the effect on the surface of particle and It is insufficient based on actual use performance.(hereinafter, the referred to as patent document moreover, U.S. Patent No. 7,364,793 16) a kind of compound and lithium-transition by wherein making that there is high-affinity for lithium and cation can be supplied is disclosed The method of composite oxide of metal reaction and the material that obtains.
Summary of the invention
However, metal salt or hydroxide are added to common uniform according to such as in the method for patent document 1 In lithium-transition metal oxide of form, the resistance of electrode increases and is difficult to obtain enough capacity.In patent document 2 In method, the reduction of the capacity due to caused by coating is very big, so that positive active material is that cannot make us for practical application Satisfied.If merely with the coating element, coating method and the coated form that are disclosed in document 3 and 4, patent document 3 and 4 Method as the technology for improving battery performance be under the high temperature conditions unsatisfactory.Moreover, it has been found that Increase coated weight and will lead to the diffusion of obstruction lithium ion to obtain abundant effect, so that it is very difficult in practical application area In charge-discharge current value under obtain enough capacity.Therefore, this method is the discovery that unsatisfactory.
It was found that the method disclosed in patent document 4 to 9 by cycle characteristics for improving to very high degree and inhibiting high Resistance in warm use process is unsatisfactory for improving, although can keep high capacity by this method.When logical The method and structure disclosed in patent document 12 is crossed to imitate when preparing positive active material, to be difficult to obtain enough recharge-discharges Rate, and capacity is largely lowered.In the method for patent document 13, if individually using surface treatment, due to The effect that this method generates is limited.In addition, when positive active material it is practical by the method that is disclosed in the document to prepare when, shape At uniform multiple layer, do not find to prevent the raised effect of resistance when especially using at high temperature.
About the method according to patent document 15, the simple metal fluoride low with electronic conductivity and lithium-ion-conducting Coating causes recharge-discharge performance to significantly reduce, and it is insufficient to the effect of the charge-discharge characteristics under hot environment 's.When the present inventor by the method that is disclosed in patent document 16 to prepare positive active material when, occur as applying It covers the inhomogeneities of the material of material addition or falls off, and generate inactive compound such as oxide and lithium fluoride, so that applying Covering function can not be sufficiently presented.Additionally, it is difficult to the recharge-discharge performance of actual use level be obtained, because charging-putting The migration of lithium ion is interrupted at solid liquid interface when electric.Furthermore, it was further observed that the trend that capacity reduces, because from lithium-transition Composite oxide of metal loses lithium.It therefore, is unsatisfactory according to the material of the document.
Very little is presented therefore, it is necessary to high, the charge-discharge cycles excellent to capacity and when being used for hot environment Deterioration positive active material, use the anode and non-aqueous electrolyte secondary battery of such positive active material and preparation The method of such positive active material.
Embodiment according to the present invention provides a kind of positive active material prepared by following steps: will contain lithium Compound, the compound containing the transition metal being included in solid solution and containing be different from transition metal metallic element The compound of M2 mixes, and is burnt into mixture to form composite oxide particle；On the surface of the composite oxide particle Deposition includes the compound selected from least one of sulphur (S), phosphorus (P) and fluorine (F) element；And firing is deposited with thereon and includes The composite oxide particle of compound selected from least one of sulphur (S), phosphorus (P) and fluorine (F) element；Thus each composite oxygen Compound particle has such concentration gradient: the concentration of metallic element M2 increases from the center of composite oxide particle to surface, And make selected from least one of sulphur (S), phosphorus (P) and fluorine (F) element to assemble (aggregate agglomerates) in combined oxidation Form on the surface of composition granule exists.
It is according to the present invention it is another embodiment there is provided it is a kind of include by following steps prepare positive active material Anode: by lithium-containing compound, the compound containing the transition metal being included in solid solution and containing be different from transition gold The compound of the metallic element M2 of category mixes, and is burnt into mixture to form composite oxide particle；In the composite oxides Deposition includes the compound selected from least one of sulphur (S), phosphorus (P) and fluorine (F) element on the surface of particle；And it is burnt into it On be deposited with comprising the composite oxide particle selected from least one of sulphur (S), phosphorus (P) and fluorine (F) compound of element；By This each composite oxide particle has such concentration gradient: the concentration of metallic element M2 is from the center of composite oxide particle Increase to surface, and makes selected from least one of sulphur (S), phosphorus (P) and fluorine (F) element to be gathered in composite oxide particle Surface on form exist.
Other embodiment there is provided a kind of non-aqueous solution electrolysis including anode, cathode and electrolyte according to the present invention Electrolyte cell, wherein anode includes the positive active material prepared by following steps: mixing lithium-containing compound, containing being included in The compound of transition metal in solid solution and compound containing the metallic element M2 for being different from transition metal, and are burnt into Mixture is to form composite oxide particle；Deposition is comprising being selected from sulphur (S), phosphorus (P) on the surface of the composite oxide particle With the compound of at least one of fluorine (F) element；And firing is deposited with thereon comprising selected from sulphur (S), phosphorus (P) and fluorine (F) At least one of the compound of element composite oxide particle；Thus each composite oxide particle has such concentration Gradient: the concentration of metallic element M2 from the center of composite oxide particle to surface increase, and make selected from sulphur (S), phosphorus (P) and At least one of fluorine (F) element exists in the form being gathered on the surface of composite oxide particle.
The positive active material of anode and nonaqueous electrolyte battery of the invention includes selected from sulphur (S), phosphorus (P) and fluorine At least one of (F) it is preferred (to thermally decompose) product for the pyrolysis of the compound of the compound or positive active material of element With 70 DEG C or more 600 DEG C of fusing points below, and further preferably there are 30 μm of average diameters below.
Embodiment there is provided a kind of methods for preparing positive active material according to another, comprising the following steps: mixing contains Lithium compound, the compound containing the transition metal being included in solid solution and containing be different from transition metal metal member The compound of plain M2, and mixture is burnt into form composite oxide particle；It sinks on the surface of the composite oxide particle Product includes the compound selected from least one of sulphur (S), phosphorus (P) and fluorine (F) element；And firing is deposited with thereon comprising choosing The composite oxide particle of at least one of bin cure (S), phosphorus (P) and fluorine (F) compound of element；Thus each combined oxidation Composition granule has such concentration gradient: the concentration of metallic element M2 increases from the center of composite oxide particle to surface, and And make the shape on surface of the element to be gathered in composite oxide particle at least one of sulphur (S), phosphorus (P) and fluorine (F) Formula exists.
Be deposited on the surface of composite oxide particle comprising selected from least one of sulphur (S), phosphorus (P) and fluorine (F) Melting is after the compound of element is preferably melted or thermally decomposes to be uniformly present on the surface of composite oxide particle.Also It is preferred that on the surface of composite oxide particle, removal be deposited on the surface of composite oxide particle comprising selected from sulphur (S), The cation of at least one of phosphorus (P) and fluorine (F) compound of element, and make the anion of compound be included in it is compound Element reaction in oxide particle.
In addition, it is according to the present invention it is another embodiment there is provided one kind include lithium-compound transition metal oxide particle Positive active material, the lithium-compound transition metal oxide particle include lithium, primary transition metal M1 and be different from main mistake The metallic element M2 of metal M1 is crossed, metallic element M2 has the concentration ladder of the metallic element M2 from from the center of each particle to surface Degree, wherein molar fraction r (%) is full in the range of ratio d (%) meets 0.020≤d≤0.050 from surface to certain depth Sufficient formula 0.20≤r≤0.80, wherein ratio d (%)=[(quality of primary transition metal M1)+(matter of metallic element M2 Amount)]/(quality of particle entirety), and wherein molar fraction r=(amount of substance of metallic element M2)/[(primary transition metal The amount of substance of M1)+(amount of substance of metallic element M2)], wherein the primary transition metal M1 be selected from nickel (Ni), cobalt (Co), At least one of manganese (Mn) and iron (Fe), and wherein, the metallic element M2 is selected from manganese (Mn), magnesium (Mg), aluminium (Al), at least one of nickel (Ni), boron (B), titanium (Ti), cobalt (Co) and iron (Fe) element.
According to the present invention another embodiment there is provided a kind of anode, which includes compound comprising lithium-transition metal The positive active material of oxide particle, the lithium-compound transition metal oxide particle include lithium, primary transition metal M1 and not It is same as the metallic element M2 of primary transition metal M1, metallic element M2 has the metallic element from the center of each particle to surface The concentration gradient of M2, wherein rubbing in the range of the ratio d (%) from surface to certain depth meets 0.020≤d≤0.050 Your score r (%) meets formula 0.20≤r≤0.80, wherein ratio d (%)=[(quality of primary transition metal M1)+(metal The quality of element M 2)]/(quality of particle entirety), and wherein molar fraction r=(amount of substance of metallic element M2)/[(master Want the amount of substance of transition metal M 1)+(amount of substance of metallic element M2)].
It is according to the present invention it is another embodiment there is provided it is a kind of including anode, cathode and electrolyte nonaqueous electrolyte Battery, anode include comprising lithium-compound transition metal oxide particle positive active material, the lithium-transition metal composite oxygen Compound particle includes lithium, primary transition metal M1 and the metallic element M2 different from primary transition metal M1, metallic element M2 tool There is the concentration gradient of the metallic element M2 from from the center of each particle to surface, wherein in the ratio d from surface to certain depth In the range of (%) meets 0.020≤d≤0.050, molar fraction r (%) meets formula 0.20≤r≤0.80, wherein ratio d (%)=[(quality of primary transition metal M1)+(quality of metallic element M2)]/(quality of particle entirety), and wherein rub That score r=(amount of substance of metallic element M2)/[(amount of substance of primary transition metal M1)+(substance of metallic element M2 Amount)].
According to the present invention, pass through the range in ratio d (%) satisfaction 0.020≤d≤0.050 from surface to certain depth Interior control molar fraction r (%) meets formula 0.20≤r≤0.80 to inhibit positive active material-electrolyte boundary anti- It answers.
In the present invention, each composite oxide particle has such concentration gradient: the concentration of metallic element M2 is from again The center for closing oxide particle increases to surface, and selected from least one of sulphur (S), phosphorus (P) and fluorine (F) element to assemble On the surface that the form on the surface of composite oxide particle is present in composite oxide particle.It may therefore be assured that positive The stabilization of active material and stabilization in interface.
According to the present invention it is possible to realize high capacity, charge/discharge cycles excellent and when being used for hot environment The battery of very little deterioration is presented.
Detailed description of the invention
Fig. 1 is to show the perspective view of the configuration example of nonaqueous electrolyte battery of embodiment according to the present invention；
Fig. 2 is the cross-sectional view of the line II-II along Fig. 1 of rolled electrode bodies shown in FIG. 1；
Fig. 3 is to show the cross-sectional view of the configuration example of nonaqueous electrolyte battery of embodiment according to the present invention；
Fig. 4 is the cross-sectional view for being illustrated in exaggerated form a part of rolled electrode bodies shown in Fig. 3；And
Fig. 5 is to show the cross-sectional view of the configuration example of nonaqueous electrolyte battery of embodiment according to the present invention.
Specific embodiment
Now, embodiments of the present invention are described below with reference to accompanying drawings.Embodiments described below is the present invention Specific example, be technically considered preferred various limitations and at the same time providing.However, unless giving in the following description The description for specific limitation of the invention is indicated out, otherwise the scope of the present invention and is not restricted by the embodiments.In addition, It will be described in the following sequence.
1. first embodiment (the first example of nonaqueous electrolyte battery)
2. second embodiment (the second example of nonaqueous electrolyte battery)
3. third embodiment (the third example of nonaqueous electrolyte battery)
4. the 4th embodiment (the 4th example of nonaqueous electrolyte battery)
5. the 5th embodiment (the 5th example of nonaqueous electrolyte battery)
6. other embodiment
[summary of the invention]
Such as cobalt acid lithium (LiCoO2) and lithium nickelate (LiNiO2) lithium-containing transition metal oxide be widely used as lithium ion Positive active material in secondary cell.However, there is the stability under their charged state in them.Especially It is that, since the reactivity of the interface between positive active material and electrolyte increases, transiting metal component can be from anode Dissolution, causes the metal of deterioration or the dissolution of active material to be precipitated in negative side.As a result, the occlusion of lithium (Li) can be hindered (embedding Enter) and release (deintercalation).
In addition, such positive active material as mentioned above is considered accelerating the decomposition reaction of interface electrolyte, lead It causes to form coating at the electrode surface or generates gas, lead to the deterioration of battery behavior.Meanwhile being suitably designed anode- Under conditions of cathode ratio, by the maximum charge electricity for reaching at least 4.20V (preferably at least 4.35V, more preferably at least 4.40V) The mode of pressure charges, the energy density of battery when charging can be improved.However, it is clear that in charging voltage liter It is high and under the high charge voltage conditions of 4.25V or more in the case where recharge-discharge cycles, active material or electrolyte Above-mentioned deterioration accelerate, cause charge-discharge cycle life reduce or High temperature storage after performance deterioration.
Therefore, the present inventor carries out extensively careful research.After study, they have found using tool In the case where the lithium metal composite oxide for having improved particle surface, the presence of the metallic compound on particle surface is to electricity The raising of pond characteristic generates high synergy or new effect.Based on the discovery make the present invention is intended to provide a kind of for pole The positive active material of the lithium ion secondary battery of the big characteristic for improving battery and stability.
1. first embodiment (the first example of nonaqueous electrolyte battery)
Fig. 1 is to show the perspective view of the configuration example of nonaqueous electrolyte battery according to the first embodiment of the present invention. The nonaqueous electrolyte battery is such as non-aqueous electrolyte secondary battery.Global shape is that the flat nonaqueous electrolyte battery has Such construction, wherein the rolled electrode bodies 10 for being equipped with positive wire 11 and negative wire 12 are contained in membranaceous package (outside Mould component) in 1.
The shape of positive wire 11 and negative wire 12 is, for example, rectangular plate-like, and they are for example from package 1 It is internal to be drawn in the same direction towards external.For example, positive wire 11 is made of the metal material of such as aluminium (Al), and example Such as, negative wire 12 is made of the metal material of such as nickel (Ni).
Package 1 by for example with insulating layer, metal layer and outermost layer with this sequence stack and by lamination etc. each other The laminated film of the structure of adherency is constituted.For example, package 1 is configured to the setting of insulating layer side in inside, and each pair of outer edge is logical It crosses melting or is fixed to one another by using adhesive.
Insulating layer by such as polyolefin resin for example polyethylene, polypropylene, modified poly ethylene, modified polypropene and they Copolymer is constituted.Such polyolefin resin guarantees low water penetration and air-tightness is excellent.Metal layer is by aluminium, stainless The foil-like or tabular component of steel, nickel, iron etc. are constituted.Outermost layer can be for example made of or the resin for being similar to insulating layer by Buddhist nun Dragon etc. is constituted.Such material guarantees there is the high intensity for preventing rupturing or pierce through.Package 1 can also have in addition to above-mentioned exhausted Edge layer, metal layer and outermost other layers.
Between package 1 and each of positive wire 11 and negative wire 12, insertion adhesive film 2 is for improving just The adhesion strength of each of pole lead 11 and negative wire 12 and the inside of package 1 and infiltration for preventing outside air Thoroughly.Adhesive film 2 is by having the material of adhesion strength (fixed to contact) performance to each of positive wire 11 and negative wire 12 It is formed.In the case where positive wire 11 and negative wire 12 are made of above-mentioned metal material, adhesive film 2 is preferably for example by polyene The formation such as hydrocarbon resin such as polyethylene, polypropylene, modified poly ethylene, modified polypropene.
Fig. 2 is cross-sectional view of the rolled electrode bodies 10 shown in FIG. 1 along the line II-II of Fig. 1.Rolled electrode bodies 10 have wherein The structure that anode 13 and cathode 14 are stacked by diaphragm 15 therebetween and electrolyte 16, and its outermost circumference passes through guarantor Protecting band 17 is protected.
[anode]
Anode 13 is for example with positive electrode collector 13A and the anode that is separately positioned on the two sides of positive electrode collector 13A Active material layer 13B.Positive electrode active material layer can be provided only on the side of positive electrode collector 13A.As positive electrode collector 13A, it is, for example, possible to use the metal foils of such as aluminium foil.
Positive electrode active material layer 13B includes that as a positive electrode active material one or more kinds of can occlude and discharge The positive electrode of electrode reaction object.Positive electrode active material layer 13B further comprises the conductive auxiliary agent of such as carbon material and such as gathers The binder of vinylidene or polytetrafluoroethylene (PTFE).
[positive active material]
Positive active material is such as composite oxide particle, includes to be different from major shift in the composite oxide particle The metallic element M2 of metal M1 and the concentration gradient with the metallic element M2 from from the center of each particle to surface.The concentration Gradient refers to as the concentration close to particle surface, metallic element M2 increases.The composite oxide particle is wherein selected from sulphur (S), at least one of phosphorus (P) and fluorine (F) element X are present on the surface of composite oxide particle with aggregated forms and contain lithium The particle of compound transition metal oxide.Incidentally, lithium-compound transition metal oxide surface state can by The powder of acquisition is observed under SEM/EDX (scanning electron microscope/energy dispersion-type X-ray spectrometer) to confirm.
Metallic element M2 is not particularly limited.It is preferable, however, that composite oxide particle is prepared by such method The particle of lithium-containing transition metal composite oxides, wherein preexist in metallic element M2 inside composite oxide particle, and And make metallic element M2 with comprising reacting selected from the compound of at least one of sulphur (S), phosphorus (P) and fluorine (F) element X to make The concentration of metallic element M2 at particle surface increases.
Therefore, metallic element M2 is evenly distributed in inside composite oxide particle in advance, then metallic element M2 The concentration on grain surface increases, it is possible thereby to which metallic element M2 is made to be uniformly present in particle surface.As a result, metallic element M2 Modified effect on grain surface can be presented to the maximum extent.
Metallic element M2 is preferably, and is based on solid solution, can replace the major shift gold in composite oxide particle inside Belong at least one element of element M 1.It is highly preferred that metallic element M2 is selected from by manganese (Mn), magnesium (Mg), aluminium (Al), nickel (Ni), at least one of group of boron (B), titanium (Ti), cobalt (Co) and iron (Fe) composition element.Metallic element M2 is main in displacement It is present in particle surface in the state of transition metal element A or in the state of the inside being diffused near particle surface to be in It is now effective to the continuous concentration gradient of each granular center.
Incidentally, the concentration of magnesium can be by cutting lithium-compound transition metal oxide section and by Auger electricity Sub- power spectrum art measures distribution radially to confirm.
In addition, for improving metallic element M2 in the metallic element M2 of the concentration of particle surface and comprising selected from sulphur (S), phosphorus (P) and preferably lower progress coexists in lithium (Li) compound in the reaction of at least one of fluorine (F) compound of element.In Li chemical combination In the case that object is reacted under coexisting, in adjustable lithium-contained composite oxide the amount of Li and inhibit due to surface modification draw The capacity risen reduces.
As lithium-compound transition metal oxide inside particle, one of various known substances can be used.However, excellent Selection of land, lithium-compound transition metal oxide are the primary transition metal elements As for having layered rock salt structure and constituting as it It is the substance selected from least one of nickel (Ni), cobalt (Co), manganese (Mn) and iron (Fe).Such material guarantee high capacity.This Outside, it also can be used and wherein have been incorporated into known substance of a small amount of addition element as substituent based on solid solution.
Incidentally, the composite oxide particle as the substrate for anode be for example with layered rock salt structure and By the lithium composite xoide particle for the average composition that following below formula (chemical formula 1) indicates.
(chemical formula 1)
LiaAbM1-bOc
In the formula, M be preferably selected from manganese (Mn), magnesium (Mg), aluminium (Al), nickel (Ni), boron (B), titanium (Ti), cobalt (Co) and At least one of iron (Fe) element；A, b and c is in the range of 0.2≤a≤1.4,0≤b≤1.0 and 1.8≤c≤2.2 Number；In addition, the component ratio of lithium changes with charge discharge state, the value of a shown herein is indicated under complete discharge condition Value.
In chemical formula (chemical formula 1), the range of the value of a is such as 0.2≤a≤1.4.If the value of a is too small, conduct The layered rock salt structure of the basic crystal structure of lithium composite xoide can destroy, so that being difficult to realize recharge and holding Amount can significantly reduce.On the other hand, if the value of a is too big, lithium can diffuse to the outside of composite oxide particle, hinder subsequent The control of basicity in processing step, and finally cause the problem of promoting gelation in the kneading process of anode sizing agent.
Incidentally, the lithium composite xoide in above formula (chemical formula 1) is arranged so as to can have more than the relevant technologies Amount containing lithium.Specifically, indicate that the value of a of the ratio of lithium in the lithium composite xoide in above formula (chemical formula 1) can be greater than 1.2.Herein, 1.2 value is carried out as the component ratio of the lithium in the lithium composite xoide of the type in the related art Disclose, and due to having with a=1 in the case where identical crystal structure, obtain working effect same as the present application (reference Such as the earlier application of the applicant: Japanese Patent Publication the 2008-251434th).
Even if notationally the value of a of the composition of lithium is greater than 1.2 in the lithium composite xoide of formula (chemical formula 1), The crystal structure of lithium composite xoide is identical in the case where being also not more than 1.2 with the value of a.In addition, even if notationally formula is (chemical Formula 1) in the value of a of composition of lithium when being greater than 1.2, if the value is not more than 1.4, with charge-discharge cycles Difference in the case that the chemical state of the transition metal of composition lithium composite xoide and a value are not more than 1.2 in redox reaction Not not less.
B value range is such as 0≤b≤1.0.If the value of b decreases below the range, the electric discharge of positive active material Capacity can reduce.On the other hand, if the value of b increases above the value, the stabilization of the crystal structure of composite oxide particle Property can reduce, cause positive active material recharge-discharge keep capacity reduce and safety reduce.
C value range is such as 1.8≤c≤2.2.It is higher than the model in the case where the value of c is lower than the range and in the value In the case where enclosing, the stability of the crystal structure of composite oxide particle can be reduced, and lead to the recharge-discharge of positive active material It keeps capacity reduction and safety reduces, and the discharge capacity of positive active material is caused to reduce.
[particle diameter]
Positive active material preferably has 2.0 μm to 50 μm of average grain diameter.If average grain diameter is less than 2.0 μm, then the removing of positive electrode active material layer can occur when suppressing positive electrode active material layer in manufacture anode process.In addition, by In the increased surface area of positive active material, it is therefore necessary to increase the additional amount of conductive auxiliary agent and binder, so that every list The energy density of position weight is tended to be lowered.On the other hand, if average grain diameter is more than 50 μm, particle tends to pierce Diaphragm is worn, short circuit is caused.
As above preferred anode 13 has the thickness no more than 250 μm.
[cathode]
Cathode 14 is for example living with negative electrode collector 14A and the cathode being separately positioned on the two sides of negative electrode collector 14A Property material layer 14B.Negative electrode active material layer 14B can be set on the only side of negative electrode collector 14A.Negative electrode collector 14A It is made of the metal foil of such as such as copper foil.
For example, negative electrode active material layer 14B, which is configured to contain, can occlude and discharge lithium as negative electrode active material At least one negative electrode material, and may include conductive auxiliary agent and/or binder if necessary.
The example that can be occluded and discharge the negative electrode material of lithium includes carbon material such as graphite, difficult graphitized carbon or Yi Shimo Change carbon, can individually or with the two or more mixtures in them come using.In addition, two kinds that average grain diameter is different Above such material can be come with mixture using.
Can occlude and discharge lithium negative electrode material other examples include those include as constitution element can be with Lithium forms the metal of alloy or the material of semimetallic elements.The specific example of such material includes that can form alloy with lithium Simple substance, alloy and the compound of metallic element and can with lithium formed alloy semimetallic elements simple substance, alloy and chemical combination Object, and its at least partly in the phase with one or more of these simple substance, alloy and compound material.
The example of such metal or semimetallic elements includes tin (Sn), lead (Pb), aluminium, indium (In), silicon (Si), zinc (Zn), antimony (Sb), bismuth (Bi), cadmium (Cd), magnesium (Mg), boron (B), gallium (Ga), germanium (Ge), arsenic (As), silver (Ag), zirconium (Zr), yttrium (Y) and hafnium (Hf), wherein it is preferred that the metal or semimetallic elements of 14 races in long period type periodic table, and particularly preferably Be silicon (Si) and tin (Sn).Silicon (Si) and tin (Sn) have the ability of high occlusion and release lithium, therefore guarantee that high-energy is close Degree.
The example of the alloy of silicon (Si) includes that those include selected from by tin (Sn), nickel (Ni), copper (Cu), iron (Fe), cobalt (Co), manganese (Mn), zinc (Zn), indium (In), silver-colored (Ag), titanium (Ti), germanium (Ge), bismuth (Bi), antimony (Sb) and chromium (Cr) form Alloy of at least one of the group as the second constitution element other than silicon (Si).The example of the alloy of tin (Sn) includes that A little includes selected from by silicon (Si), nickel (Ni), copper (Cu), iron (Fe), cobalt (Co), manganese (Mn), zinc (Zn), indium (In), silver (Ag), titanium (Ti), at least one of group of germanium (Ge), bismuth (Bi), antimony (Sb) and chromium (Cr) composition is as the other than tin (Sn) The alloy of two constitution elements.
It includes compounds of oxygen (O) or carbon (C) that the example of the compound of silicon (Si) or tin (Sn), which includes those, and the change Closing object may include one of above-mentioned second constitution element other than silicon (Si) or tin (Sn) or a variety of.
[diaphragm]
Diaphragm 15 can by using electrically it is stable, relative to positive active material, negative electrode active material and solvent Chemically stable and nonconducting any material is formed.The example for the material that can be used herein includes macromolecule nonwoven The paper-like plate of cloth, perforated membrane and glass or ceramic fibre can be used in the form of multilayer laminated body.It is particularly preferably more Hole polyolefin film, can be to have the shape of the compound by the heat proof material of the formation such as polyimides, glass or ceramic fibre Formula uses.
[electrolyte]
Electrolyte 16 includes electrolyte and the keeping body that can be used for keeping electrolyte, which includes macromolecule chemical combination Object, and be so-called gelation state.Electrolyte includes electrolytic salt and the solvent that can be used for dissolving electrolytic salt.Electrolyte The example of salt includes such as LiPF6、LiClO4、LiBF4、LiN(SO2CF3)2、LiN(SO2C2F5)2And LiAsF6Lithium salts, can Individually or with the two or more mixtures in them to use.
The example of solvent includes the lactone of gamma-butyrolacton, gamma-valerolactone, δ-valerolactone, 6-caprolactone etc., such as Ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, dimethyl carbonate, methyl ethyl carbonate, carbonic acid diethyl The carbonate solvent of ester etc., such as 1,2- dimethoxy-ethane, 1- ethyoxyl -2- Ethyl Methyl Ether, 1,2- diethoxyethane, The ether solvents of tetrahydrofuran, 2- methyltetrahydrofuran etc., the nonaqueous solvents of the nitrile solvents such as acetonitrile, such as sulfolane solvent, The nonaqueous solvents of phosphoric acid class, phosphate ester solvent and pyrrolidones.These solvents can be individually or with two or more in them Mixture come using.
In addition, solvent preferably comprises the compound having a structure in which, in the structure, cyclic ester or ol ester Hydrogen moiety is all fluorinated and (is replaced by fluorine atom).What it is preferably as fluorinated compound is two fluoroethylene of carbonic acid (the fluoro- 1,3- dioxolan-2-one of 4,5- bis-).Even if using the chemical combination for including silicon (Si), tin (Sn), germanium (Ge) etc. as a result, In the case where cathode 14 of the object as negative electrode active material, charge-discharge cycles characteristic can also be improved.In particular, carbonic acid two Fluoroethylene has excellent improvement to cycle characteristics.
High-molecular compound can be it is any by lyosoption by the high-molecular compound of gelatine.Macromolecule chemical combination The example of object includes fluoro high-molecular compound such as Kynoar, vinylidene fluoride-hexafluoropropylene copolymer etc., ether producing high-molecular Object such as polyethylene oxide, cross-linked polymer containing polyethylene oxide etc. are closed, and includes polyacrylonitrile, polypropylene oxide or poly- first High-molecular compound of the base methyl acrylate as repetitive unit.These high-molecular compounds can be individually or in them Two or more mixtures come using.
In particular, fluoro high-molecular compound is desired from the viewpoint of oxidation-reduction stability, wherein comprising inclined Vinyl fluoride and hexafluoropropene are preferred as the copolymer of component.Moreover, copolymer may include the list of unsaturated dibasic acid The ring of the ethylene halide of ester such as monomethyl maleate etc., trifluoro-ethylene etc., such as vinylene carbonate unsaturated compound Shape carbonic ester or acryloyl group vinyl monomer containing epoxy group are as component, so that it can obtain higher spy Property.
In addition, inorganic solid electrolyte and polymer solid electrolyte can be used as solid electrolyte, as long as this is solid Body electrolyte has lithium-ion-conducting.The example of inorganic solid electrolyte includes lithium nitride and lithium iodide.Macromolecular solid Body electrolyte includes electrolytic salt and the high-molecular compound that can be used for dissolving the electrolytic salt.The example of high-molecular compound Including ether macromolecule for example poly- (ethylene oxide), its cross-linking products etc., poly- (methacrylate) macromolecule, acrylate polymeric Deng they can be used alone or as the two or more copolymer in them or with two or more mixed in them Object is closed to use.
[method of manufacture anode]
Firstly, including the composite oxide particle of metallic element M1 in the synthesis present invention.For synthesizing composite oxide The mode of grain is not particularly limited.Moreover, as making composite oxide particle and comprising selected from sulphur (S), phosphorus (P) and fluorine At least one of (F) compound of element reacts the raised method of concentration so that the metallic element M2 in particle surface, can Using known various methods.
In addition, the method on the surface for coating composite oxide particle includes such method, wherein by using ball Grinding machine, crusher, pulverizer etc. make lithium-compound transition metal oxide containing metallic element M2 and comprising selected from sulphur (S), phosphorus (P) it is crushed with the compound of at least one of fluorine (F) element, mixes and coat (deposition).In carrying out the operation, it is added one Quantitative liquid component (can be such as water) is effective.In addition it is also possible to (heavy using the coating handled by mechanochemistry Product) or such as sputtered by vapor phase method, the coating (deposition) of CVD (chemical vapor deposition) metallic compound.
Moreover, by water or in the solvent of such as ethyl alcohol mixed raw material, pass through the knot via sum in the liquid phase It is brilliant or by other similar approach can the upper formation of lithium-compound transition metal oxide include selected from sulphur (S), phosphorus (P) and The surface of at least one of fluorine (F) element.Making selected from least one of sulphur (S), phosphorus (P) and fluorine (F) element thus After being present on lithium-compound transition metal oxide comprising metallic element M2, preferably it is heat-treated so that metallic element M2 is increased in the concentration of particle surface.For example, can be heat-treated at 350 DEG C to 900 DEG C.Lithium-transition metal of acquisition Composite oxides can be the composite oxides for having passed through the known technical treatment for being used to control powder property.
Then, the conductive auxiliary agent of positive active material, binder and such as carbon material is mixed to prepare anode Composition.The positive electrode composition is dispersed in the solvent of such as n-methyl-2-pyrrolidone, to prepare positive electrode composition slurry Material.Binder can be Kynoar, polytetrafluoroethylene (PTFE) etc..
Then, which is applied to positive electrode collector 13A, and dry.Later, using roll squeezer etc. Compression forming is carried out to form positive electrode active material layer 13B, thus to obtain anode 13.Incidentally, if it is desired, preparing just The conductive auxiliary agent of such as carbon material is mixed when the composition of pole.
[method of manufacture cathode]
Then, cathode 14 is manufactured in the following manner.Firstly, by negative electrode active material and binder be mixed with each other with Cathode composition is prepared, and the cathode composition is dispersed in the solvent of such as n-methyl-2-pyrrolidone, it is negative to prepare Pole combination pulp.Then, which is applied to negative electrode collector 14A, and evaporates solvent.It Afterwards, compression forming is carried out to form negative electrode active material layer 14B, thus to obtain cathode 14 using roll squeezer etc..
[method of manufacture nonaqueous electrolyte battery]
For example, nonaqueous electrolyte battery can be manufactured in the following manner.Firstly, will include electrolyte, macromolecule chemical combination The precursor solution of object and mixed solvent is applied on positive each of 13 and cathode 14, and evaporates mixed solvent, with Form electrode 16.Later, positive wire 11 is connected by welding to the end of positive electrode collector 13A, and by negative wire 12 are connected by welding to the end of negative electrode collector 14A.
Then, by the anode 13 for being formed with electrolyte 16 and cathode 14 by diaphragm 15 therebetween be stacked with Stacked body is formed, which is wound along the longitudinal direction, and protection band 17 is adhered to the outermost circumference of coiling body, with shape At rolled electrode bodies 10.Finally, for example, rolled electrode bodies 10 are clipped between package 1, and keep the peripheral part of package 1 logical It crosses heat fusing etc. to be adhering to each other, rolled electrode bodies 10 is sealed in package 1.In this case, adhesive film 2 is inserted into To between each of each of positive wire 11 and negative wire 12 and package 1.In this way, complete such as Fig. 1 and Nonaqueous electrolyte battery shown in Fig. 2.
Further, it is also possible to manufacture nonaqueous electrolyte battery in the following manner.Firstly, manufacturing positive 13 Hes in the above described manner Cathode 14, and positive wire 11 and negative wire 12 are adhered to anode 11 and cathode 12 respectively.Then, by anode 13 and negative Pole 14 is stacked by diaphragm 15 therebetween to form stacked body, winds the stacked body, and protection band 17 is adhered to The outermost circumference of coiling body, to form the coiling body as the precursor of rolled electrode bodies 10.Then, which is clipped in packaging Between part 1, the outer peripheral edge portion other than a side of package 1 is hot-melted to obtain bag shape, it thus will volume It is contained in package 1 around body.Then, it prepares containing electrolyte, the monomer as the raw material for high-molecular compound, polymerization The electrolyte composition of initiator and other materials (if necessary) such as polymerization inhibitor, which is introduced Into package 1.
After introducing electrolyte composition, by being hot-melted come the opening portion of sealed package 1 under vacuum atmosphere.It connects , heat will be applied so that gel electrolyte 16 is consequently formed to form high-molecular compound in a kind of monomer or various of monomer polymerization, And assemble nonaqueous electrolyte battery as depicted in figs. 1 and 2.
The improvement details of cycle characteristics etc. is still unclear, but it is believed that the improvement is realized by following mechanism.It is filling In the lithium ion secondary battery of electricity condition, anode is in Strong oxdiative state, and the electrolyte contacted with anode is in and is easy hair The environment of raw oxygenolysis, especially under high temperature environment.When electrolyte is decomposed, on the surface of positive active material Torpescence film is formed, the migration of electronics and/or lithium ion is thus prevented.
Moreover, the component decomposed generates the high molecule of activity in the electrolyte present in the hole of electrode, to accelerate electricity Thus deterioration or attack (corrosion) positive active material for solving liquid dissolve the constitution element of positive active material or reduce capacity. Such in order to inhibit the phenomenon that, only the interface between stable positive active material particle and electrolyte is insufficient, above-mentioned steady The outside and the bioactive molecule near it for being set for and stablizing positive active material particle must carry out cooperatively.
In lithium-containing transition metal oxide in embodiments of the present invention, make to be different from the master inside oxide particle The metallic element M2 of transition metal is wanted to be present on particle surface, so that the interface between active material particle and electrolyte is steady It is fixed.In addition, make comprising lithium-compound transition metal oxide selected from least one of sulphur (S), phosphorus (P) and fluorine (F) element with Aggregated forms are present near particle, so that bioactive molecule stabilizes.It is believed that the collaboration due to these stabilizations is imitated Fruit, battery performance are improved considerably.
Furthermore, it is believed that then making metallic element M2 due to making metallic element M2 be uniformly present in the inside of particle in advance Concentration at particle surface increases, to ensure that metallic element M2 is uniformly present in particle surface, so metallic element M2 Stablizing effect can be presented to the maximum extent, to successfully improve battery performance.
[effect]
Nonaqueous electrolyte battery in first embodiment according to the present invention can inhibit the deterioration of cycle characteristics, suppression It makes the internal resistance due to caused by charge-discharge cycles under high temperature environment to increase, and it is possible thereby to realizes raising simultaneously Capacity and improved battery behavior.
2. second embodiment (the second example of nonaqueous electrolyte battery)
Second embodiment of the present invention will be described.Nonaqueous electrolyte battery according to the second embodiment of the present invention makes With the positive active material with more evenly coating.
Since other materials and construction are identical as in first embodiment, the explanation about them is omitted.
[positive active material]
Positive active material is for example wherein comprising being different from primary transition metal M1 and having from the center of each particle Towards the composite oxide particle of the metallic element M2 of the concentration gradient of the metallic element M2 on surface.Concentration gradient refers to connecing The concentration of nearly particle surface metallic element M2 increases.Composite oxide particle is the particle of lithium-containing transition metal composite oxides, Wherein it is present in the table of composite oxide particle with aggregated forms selected from least one of sulphur (S), phosphorus (P) and fluorine (F) element X Face.
In this second embodiment, comprising selected from least one of sulphur (S), phosphorus (P) and fluorine (F) compound of element or The decomposition product of the compound has 70 DEG C or more 600 DEG C of fusing points below.It is such as located in using ball mill by certain way The decomposition product of the compound or the compound on the surface of composite oxides is melted by heating, to be evenly coated with The surface of composite oxides.Hereafter, make the decomposition product and composite oxides of the compound or the compound that heat and melt anti- It answers.So that coating is more more effective than first embodiment and more evenly.
When higher than 600 DEG C at a temperature of heat the decomposition product of the compound or the compound when, composite oxygen will be caused The structure reacted and can change composite oxides in compound.But in the present embodiment, make the compound or the change The decomposition product for closing object melts and coats composite oxides to answer before the structure change of composite oxides with stable state Close oxide reaction.
If the fusing point of the decomposition product of the compound or the compound is higher than 600 DEG C, in compound or product melt And start coating reaction before the surface for coating composite oxide particle, and compound or the product and composite oxides it Between reaction start, only the position that compound or the product are contacted with composite oxides provide part coating reaction, this Lead to the unfavorable non-homogeneous coating on composite oxides.
Greater than 600 DEG C at a temperature of heating also result in the structure changes of composite oxides.
If the fusing point of the compound or the decomposition product is less than 70 DEG C, the compound or the product are passing through ball mill Deng deposition process in adversely will melt or decompose.
The decomposition product of the compound or the compound preferably has 30 μm of average diameters below.Such diameter is somebody's turn to do Compound or the decomposition product will realize the uniform coating of composite oxides.When the compound or the decomposition product diameter are too big When, using ball mill etc., they cannot be mixed with composite oxides well, lead to the nonuniform deposition on composite oxides. The diameter of the compound or the decomposition product does not have lower limit.Smaller diameter will provide coating more evenly.But diameter is practical On be ground into about 1 μm by the compound or the decomposition product and limited.
The example of compound is diammonium hydrogen phosphate ((NH4)2HPO4), ammonium dihydrogen phosphate (NH4H2PO4), ammonium sulfate ((NH4)2HPO4), phosphoric acid (H3PO4) etc..The cation of these compounds is removed for example, by evaporating when heated, therefore can be obtained There is no the positive active material of impurity, it can reduction to avoid capacity and other deleterious effects.
As the metallic element M2 for being different from primary transition metal M1, can use and identical metal in embodiment 1 Element M 2.
[method of manufacture positive active material]
For example, the positive active material of second embodiment can be prepared according to following procedure.
Firstly, coating the surface of composite oxide particle with coating material.About for coating composite oxide particle Surface illustrative methods, can using with method identical in first embodiment, wherein by using ball mill, pulverizing The crushing such as machine, pulverizer include lithium-compound transition metal oxide of metallic element M1 and comprising selected from sulphur (S), phosphorus (P) and fluorine At least one of (F) compound of element X, mixes and coats (deposition).
In carrying out the operation, it is effective that a certain amount of liquid component (such as can be water), which is added,.In addition it is also possible to Using the coating (deposition) handled by mechanochemistry or by the way that vapor phase method such as sputters, CVD (chemical vapor deposition) uses metal The coating (deposition) of compound.
Thus to be present in selected from least one of sulphur (S), phosphorus (P) and fluorine (F) element X comprising metallic element M1 Lithium-compound transition metal oxide on after, be preferably heat-treated so that concentration of the metallic element M2 at particle surface It increases.For example, can be heat-treated at 700 to 900 DEG C.Lithium-the compound transition metal oxide obtained can be made to be subjected to For controlling the processing of the known technology of powder property or some other purposes.
During heat treatment, the compound on the surface of composite oxides is melt into liquid condition and makes The surface of composite oxides is uniformly coated by compound.After further heat treatment, compound decomposes and cationic quilt Removal, and anion with include that metallic element M2 in composite oxides reacts.Compound melts with coating material The temperature of heat treatment can be increased after reaction.
[effect]
According to second embodiment, combined oxidation can be coated with coating material before the structure change of composite oxides Object.Therefore, the function that can improve positive active material leads to the better performance of non-aqueous electrolyte secondary battery.
3. third embodiment (the third example of nonaqueous electrolyte battery)
Third embodiment of the present invention will be described.Nonaqueous electrolyte battery according to the third embodiment of the present invention makes The gel electrolyte 16 in nonaqueous electrolyte battery according to the first embodiment of the present invention is replaced with electrolyte.In this feelings Under condition, electrolyte is used by impregnating diaphragm 15 with it.As electrolyte, can be used with it is identical in first embodiment Electrolyte.
For example, the nonaqueous electrolyte battery thus constructed can be manufactured in the following manner.Firstly, manufacturing anode 13 and bearing Pole 14.Anode 13 and cathode 14 can be manufactured in a manner of identical with above-mentioned first embodiment, therefore omit system herein The detailed description made.
Then, after positive wire 11 and negative wire 12 to be respectively connected to anode 13 and cathode 14, by positive 13 Hes Cathode 14 is stacked by diaphragm 15 therebetween together to form stacked body, winds layered product, and protection band 17 is adhered to volume Around the outermost circumference of body.
As a result, rolled electrode bodies identical with the construction of above-mentioned rolled electrode bodies 10 are obtained, the difference is that, it omits Electrolyte 16.After coiling body is clipped between package 1, electrolyte is introduced into the inside of package 1, and seals packet Piece installing 1.In this way, nonaqueous electrolyte battery according to the third embodiment of the present invention is obtained.
[effect]
Third embodiment according to the present invention, can obtain effect same as the first embodiment.It specifically, can be with Inhibit the deterioration of cycle characteristics, inhibits the raising of the internal resistance due to caused by charge-discharge cycles under high temperature environment, and It is possible thereby to realize the capacity and improved battery behavior of raising simultaneously.
4. the 4th embodiment (the 4th example of nonaqueous electrolyte battery)
Then, the structure of nonaqueous electrolyte battery according to the fourth embodiment of the present invention will be described referring to Fig. 3 and Fig. 4 It makes.Fig. 3 shows the construction of nonaqueous electrolyte battery according to the fourth embodiment of the present invention.
The nonaqueous electrolyte battery is so-called cylindrical battery, wherein wind band-like positive 31 and band-like cathode 32 and Diaphragm 33 between them forms rolled electrode bodies 30, which is arranged on substantially hollow cylindrical battery shell 21 inside.
Diaphragm 33 is impregnated with the electrolyte as liquid electrolyte.Battery case 21 by such as nickel plating (Ni) iron (Fe) shape At.Battery case 21 is closed at one end, and is unlimited in its other end.In the inside of battery case 21, by a pair of of insulation board 22 and 23 outer peripheral surfaces for being respectively perpendicular to rolled electrode bodies 30 are arranged on the two opposite sides of rolled electrode bodies 30.
In the open end of battery case 21, battery cover 24 and 25 He of relief valve mechanism that 24 inside of battery cover is set PTC (positive temperature coefficient) thermistor element 26 using 27 caulked of washer by being installed.Sealed cell shell 21 is interior as a result, Portion.
Battery cover 24 is made of material for example identical with battery case 21.Relief valve mechanism 25 passes through thermistor element 26 And it is electrically connected with battery cover 24.The relief valve mechanism 25 is configured to make in battery when due to internal short-circuit or external heating When portion's pressure is more than predetermined value, discoid plate 25A is overturn to cut off being electrically connected between battery cover 24 and rolled electrode bodies 30.
When the temperature increases, thermistor element 26 limits electric current by increasing its resistance, to prevent by high current Caused abnormal heating.Washer 27 is formed by such as insulating materials, and its surface is coated with pitch.
For example, rolled electrode bodies 30 are wound centered on centrepin 34.It, will be by shapes such as aluminium (Al) in rolled electrode bodies 30 At positive wire 35 be connected to anode 31, and cathode 32 will be connected to by the negative wire 36 of the formation such as nickel (Ni).Make anode Lead 35 is electrically connected to battery cover 24 and being soldered to relief valve mechanism 25, and makes negative wire 36 by being soldered to battery case 21 and be electrically connected to battery case 21.
Fig. 4 is to show the cross-sectional view of a part shown in Fig. 3 for winding electric collective 30 in the way to enlarge.Winding electricity collection Body 30 has a structure in which, wherein anode 31 and cathode 32 are stacked to be formed and be stacked by diaphragm 33 therebetween Body, and wind the stacked body.
Anode 31 includes that such as positive electrode collector 31A and the anode being separately positioned on the two sides of positive electrode collector 31A are living Property material layer 31B.Cathode 32 includes such as negative electrode collector 32A and is separately positioned on negative on the two sides of negative electrode collector 31A Pole active material layer 32B.Positive electrode collector 31A, positive electrode active material layer 31B, negative electrode collector 32A, negative electrode active material layer The composition of 32B, diaphragm 33 and electrolyte are respectively equivalent to positive electrode collector 13A, positive electrode active material in above-mentioned first battery Those of matter layer 13B, negative electrode collector 14A, negative electrode active material layer 14B, diaphragm 15 and electrolyte are constituted.
[method of manufacture nonaqueous electrolyte battery]
Now, the method for manufacturing nonaqueous electrolyte battery according to the fourth embodiment of the present invention will be described below. Such as get off to manufacture anode 31.Firstly, positive active material and binder are mixed with each other to prepare positive electrode composition, by the anode Composition is dispersed in the solvent of such as n-methyl-2-pyrrolidone, to prepare positive electrode composition slurry.Then, by the anode Combination pulp is applied to positive electrode collector 31A, and dry.Later, compression forming is carried out to be formed just using roll squeezer etc. Pole active material layer 31B, thus to obtain anode 31.
Manufacture cathode 32 in the following manner.Firstly, being mixed with each other negative electrode active material and binder with preparation The cathode composition is dispersed in the solvent of such as n-methyl-2-pyrrolidone by cathode composition, to prepare cathode composition Slurry.Then, which is applied to negative electrode collector 32A, and evaporates solvent.Later, using roll-in Machine etc. carries out compression forming to form negative electrode active material layer 32B, thus to obtain cathode 32.
Then, positive wire 35 is connected to positive electrode collector 31A by welding etc., and negative wire 36 is passed through into welding Etc. being connected to negative electrode collector 32A.Later, the stacked body of winding anode 31 and cathode 32 and the diaphragm 33 between them, will The top end part of positive wire 35 is soldered to relief valve mechanism 25, and the top end part of negative wire 36 is soldered to battery case 21.
Then, the stacked body of anode 31 and cathode 32 is clipped between a pair of of insulation board 22 and 23, and is contained in battery In shell 21.After anode 31 and cathode 32 are contained in battery case 21, electrolyte is introduced into the inside of battery case 21, so that Diaphragm 33 impregnates electrolyte.
Later, battery cover 24, relief valve mechanism 25 and thermistor element 26 are fixed to and with 27 caulked of washer The open end of battery case 21.In this way, nonaqueous electrolyte battery shown in Fig. 3 has been manufactured.
[effect]
In nonaqueous electrolyte battery according to the fourth embodiment of the present invention, gas can be inhibited to generate, and prevent Cell fracture caused by only being increased due to internal pressure.
5. the 5th embodiment (the 5th example of nonaqueous electrolyte battery)
Nonaqueous electrolyte battery according to the fifth embodiment of the present invention uses the positive-active with more evenly coating Substance, instead of the positive active material in the nonaqueous electrolyte battery of the 4th embodiment.
Due to other materials and constitute, omission explanation about they identical with the 4th embodiment.
[positive active material]
In the range of the ratio d (%) from surface to certain depth meets 0.020≤d≤0.050, the 5th embodiment The molar fraction r (%) of positive active material meet formula 0.20≤r≤0.80.Ratio d and molar fraction r are according to following Formula determines.
Ratio d (%)=[(quality of primary transition metal M1)+(quality of metallic element M2)]/(matter of particle entirety Amount) (I)
Molar fraction r=(amount of substance of metallic element M2)/[(amount of substance of primary transition metal M1)+(metallic element M2 Amount of substance)] (II)
Other than above-mentioned point, the positive active material of the 5th embodiment is identical as the 4th embodiment.
The quality of primary transition metal M1 and the quality of metallic element M2 can be known as follows: lithium-transition metal is compound The surface of oxide is dissolved in buffer solvent, analyzes the primary transition metal M1 and metallic element M2 being dissolved in buffer solvent Mass content.
Specifically, ratio d (%) and molar fraction ratio r can be such as determinations of getting off.Firstly, buffer solvent is added to In lithium-compound transition metal oxide particle and mix them.Then, per Sample buffer solvent, and mistake at regular intervals Filter solvent.Measured by inductively coupled plasma method include primary transition metal M1 in each buffer solvent quality and The quality of metallic element M2.
The amount [mol] of metal M1 and metallic element M2 is calculated according to the quality, and is obtained according to formula (I) and (II) Ratio d and molar fraction r.Herein, particle is assumed to spherical shape, and it is assumed that the diameter for the particle being dissolved in buffer solvent exists It is calculated under the conditions of becoming smaller in the state of keeping spherical.
The above-mentioned analysis on the surface of positive active material is three-dimensional, and is capable of providing the quantitative analysis of concentration gradient, It is difficult to realize by the conventional method of analysis of the surface state of positive active material.
Under conditions of in the range of molar fraction ratio r (%) falls in 0.20≤r≤0.80, wherein from surface to one The ratio d (%) of depthkeeping degree meets 0.020≤d≤0.050, and capacity retention ratio and High temperature storage capacity are higher.
However even if molar fraction ratio r (%) is fallen in the range of 0.20≤r≤0.80, wherein from surface to certain The ratio d (%) of depth is simultaneously unsatisfactory for 0.020≤d≤0.050, exists and not necessarily has capacity retention ratio and high temperature dwell sustainability The trend of improvement.
It is preferred that in the range of the ratio d (%) from surface to certain depth meets 0.020≤d≤0.050, molar ratio r (%) is reduced from surface to inside, especially can be significant because can be to avoid the reduction of capacity retention ratio and high temperature dwell sustainability Avoid the reduction of capacity retention ratio.
In addition to the molar fraction ratio r when the ratio d (%) from surface to certain depth meets 0.020≤d≤0.050 (%) is fallen in outside in the range of 0.20≤r≤0.80, further preferably meets 0.010 in the ratio d (%) from surface to certain depth In the range of≤d < 0.020, molar ratio r meet 0.55≤r≤1.0 because can to avoid discharge capacity reduction and can To improve cycle performance and High temperature storage performance.
[method of manufacture battery]
The method for manufacturing the non-aqueous electrolyte secondary battery of the 5th embodiment is as follows.
Firstly, make lithium-compound transition metal oxide particle comprising lithium, primary transition metal M1 and metallic element M2 with It is mixed comprising the compound selected from least one of sulphur (S), phosphorus (P) and fluorine (F) element X.Preferably further mixing includes lithium Compound.Then, it is realized by mechanochemistry processing comprising selected from least one of sulphur (S), phosphorus (P) and fluorine (F) member The compound of plain X and preferably comprise deposition of the compound of lithium on lithium-compound transition metal oxide surface.To mixing 2 hours or less the processing of object mechanochemistry 5 minutes or more.When mechanochemistry processing shorter than 5 minutes, coating is insufficient, and just Pole active material particle is ground into the more little particle with too minor diameter.
Then, lithium-compound transition metal oxide particle is fired, to obtain positive active material.Temperature for firing Preferably 500 DEG C to 1500 DEG C.If temperature is lower than 500 DEG C, lithium-compound transition metal oxide particle cannot be applied sufficiently It covers.However, particle aggregation causes the coating on collector to be deteriorated at second particle if temperature is higher than 1500 DEG C.
After firing, lithium-compound transition metal oxide particle has the metal from the center of each particle towards surface The concentration gradient of element M 2.Particle includes to be deposited on the surface of composite oxide particle to be selected from sulphur (S), phosphorus with aggregated forms (P) and at least one of fluorine (F) element X.
In general, molar ratio r can be by using comprising selected from least one of sulphur (S), phosphorus (P) and fluorine (F) element X The additive amount of compound adjust.When compound addition is very little, react too small so that enough coatings cannot be obtained, and Molar ratio r is reduced.When additive amount is larger, molar ratio r becomes larger, but 1 is not more than in r principle.It reacts from table Face is carried out to inside, therefore when additive amount is larger, is obtained by the biggish part ratio d (%) from surface to certain depth high Molar ratio.
When coating material (i.e. compound or decomposition product) and substrate (i.e. lithium-compound transition metal oxide) are without fine When mixing, molar fraction ratio r is reduced.For example, the diameter of compound is 100 μm or more, it is greater than 5 μm of positive active material extremely 30 μm of average diameter, and non-homogeneous dispersion.Therefore, there is no preferred coating state, and molar fraction ratio r has When become lower.About mixed technology, any technology can be used, as long as substrate and coating material mix well, The preliminary technology of mixture etc. in planetary-type mixer, shake bag.
After obtaining positive active material, it can take with identical program in the 4th embodiment to obtain the 5th implementation The nonaqueous electrolyte battery of mode.
The upper limit of the charging voltage of the battery of 4th embodiment can be 4.2V, it is preferred that being designed to be higher than 4.2V. In particular, design battery makes the upper limit of charging voltage be preferably 4.25V to 4.80V, it is more excellent from the viewpoint of discharge capacity 4.35V or more is selected, is from a security point of view 4.65V or less.The lower limit of the discharge voltage of battery be preferably 2.00V extremely 3.30V.Designing high cell voltage leads to high-energy density.
6. other embodiment (deformation)
The present invention is not limited to above embodiment of the invention, and various modifications and application within the scope of the invention It is possible.For example, the shape of nonaqueous electrolyte battery is not limited to the above-mentioned type (cylindrical type), and it for example can be coin Type.
In addition, it is, for example, possible to use the polymer solid electrolyte for including ionic conductive high molecular material or including ion The inorganic solid electrolyte of conducting inorganic material is as electrolyte.The example of ionic conductive high molecular material includes polyethers, gathers Esters, polyphosphazene and polysiloxanes.The example of inorganic solid electrolyte includes ionic conductivity ceramics, ion conductive crystal and ion Electro-conductive glass.
The positive active material of the 5th embodiment can be used in first to third embodiment battery.
[embodiment]
Now, it will be specifically described the present invention by the embodiment shown, these embodiments are not construed as to this hair Bright limitation.
In embodiment 1-1 to 1-13 and comparative example 1-1 into 1-9, change the addition volume of coating material, and determine tool There is the battery performance for the positive electrode that the distribution of coating material is different on the surface of composite oxides.
<embodiment 1-1>
[positive manufacture]
With the molar ratio mixed carbonic acid lithium (Li of Li:Co:Al:Mg=1.00:0.98:0.01:0.012CO3), oxidation Cobalt (Co3O4), aluminium hydroxide (Al (OH)3) and magnesium carbonate (MgCO3) after, it is burnt into air at 900 DEG C mixture 5 hours, To obtain lithium-cobalt composite oxide (LiCo0.98Al0.01Mg0.01O2).The average grain diameter of lithium-cobalt composite oxide is by swashing Light scattering method measures, and is 13 μm.
Then, lithium carbonate (Li is weighed2CO3) and diammonium hydrogen phosphate ((NH4)2HPO4) and and lithium-cobalt composite oxide (LiCo0.98Al0.01Mg0.01O2) mixing, to obtain the atom ratio of Co:Li:P=98:1:1.Then, pass through mechanochemistry System processing includes mixing material 1 hour of lithium-cobalt composite oxide.As a result, the precursor before being fired, wherein lithium-cobalt Material exists centered on the particle of composite oxides, and lithium carbonate and diammonium hydrogen phosphate deposition are at the surface of the particles.
It is heated up with the rate of 3 DEG C/min to the precursor before firing, and is maintained at 900 DEG C 3 hours, then slowly It is cooling, belong to lithium-compound transition metal oxide of the invention to obtain.Lithium-the compound transition metal oxide has uniform The magnesium (Mg) being distributed on the surface of lithium-cobalt composite oxide particle.In addition, the concentration of magnesium (Mg) compares on the surface of particle The inside of particle wants high, and lithium phosphate (Li3PO4) spread at the surface of the particles.
Incidentally, lithium-compound transition metal oxide surface state at SEM/EDX by observing the powder of acquisition To confirm.After observing lithium-compound transition metal oxide surface, it was confirmed that magnesium (Mg) being uniformly distributed at the surface of the particles With the distribution of phosphorus at the surface of the particles.In addition, the concentration of magnesium, which passes through, cuts lithium-compound transition metal oxide section, and lead to The Elemental redistribution of auger electron spectrometry radial direction is crossed to confirm.In measurement lithium-compound transition metal oxide section After Elemental redistribution, the concentration of magnesium is proved to be from the surface of particle internally consecutive variations.
In addition, having when carrying out the measurement of powder X-ray diffraction pattern to powder by using CuK α in addition to being equivalent to The LiCoO of layered rock salt structure2Diffraction maximum except, have also demonstrated and be equivalent to Li3PO4Diffraction maximum.
As a positive electrode active material by using the lithium-compound transition metal oxide as above obtained, non-water power has been manufactured Electrolitc secondary cell is solved, and has rated the high-temperature cycle and internal resistance variation of battery as described below.
By mix the above-mentioned positive active material of 98wt%, 0.8wt% amorphous carbon powder (Ketjen black) and The Kynoar (PVdF) of 1.2wt% prepares positive electrode composition.The positive electrode composition is dispersed in N- methyl -2- pyrrolidines To prepare positive electrode composition slurry in ketone (NMP), then it is equably applied to the positive electrode collector being made of band-like aluminium foil Two sides.Then, the positive electrode composition slurry in current of warm air on the surface of dry positive electrode collector, and using roll squeezer into Row compression forming, to form positive electrode composition layer.
[manufacture of cathode]
Cathode composition is prepared by the PVdF of the powdered graphite and 5wt% that mix 95wt%.By the cathode composition It is dispersed in n-methyl-2-pyrrolidone to prepare cathode composition slurry, then it is equably applied to by band-like copper foil The two sides of the negative electrode collector of composition, are then pressed under heating, to form cathode composition layer.
[preparation of electrolyte]
In the mixed solvent obtained and volume mixture ethylene carbonate (EC) and methyl ethyl carbonate (MEC) with 1:1 In, dissolve lithium hexafluoro phosphate (LiPF6) to obtain 1mol/dm3Concentration, to prepare nonaqueous electrolytic solution.
[assembly of battery]
By band-like anode manufactured as above and cathode and the diaphragm being made of porous polyolefin between them to be stacked on State winding together is multiple, to manufacture spiral wound electrode body.The rolled electrode bodies are contained in by the iron of nickel plating At battery case in, and by insulation board setting in the upper surface of rolled electrode bodies and following.Then, it will be connect with negative electrode collector The negative terminal of nickel be soldered to the bottom of battery case.In addition, the positive terminal for the aluminum connecting with positive electrode collector is welded It is connected to the protruding portion ensured with the safety valve of battery cover electrical conduction.
Finally, nonaqueous electrolytic solution is introduced into the battery case for being wherein combined with rolled electrode bodies.Later, can pass through Carry out caulked battery case using insulated enclosure washer, with fixed valve, PTC thermistor element and battery cover.In this way, it manufactures Cylindrical battery with 18mm outer diameter and 65mm height.
[evaluation of battery]
(a) initial capacity
Perseverance is carried out with the charging current of 1.5A to cylindrical battery manufactured as above in the environment of 45 DEG C of ambient temperature Electric current charges until the charging voltage of 4.35V.Then, constant current charge is converted to constant voltage and is charged, and when total charging Between terminate to charge when reaching 2.5 hours.It is discharged immediately with the discharge current of 2.0A battery later, and works as cell voltage Terminate to discharge when being reduced to 3.0V.The discharge capacity of measurement in this case is found to be 9.1Wh as initial capacity.
(b) capacity retention ratio
To carry out repeating to fill to battery with recharge-discharge condition identical in the above situation for measuring initial capacity Electricity-discharge cycles.After 300 circulations, discharge capacity is measured, and determine the capacity retention ratio based on initial capacity.Capacity Conservation rate is 82%.
<embodiment 1-2>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, when charging Cell voltage be 4.20V.When evaluating battery, discovery initial capacity is 8.0Wh, and capacity retention ratio is 82%.In passing It refers to, the concentration distribution and work of the element in positive active material in embodiment 1-2 and latter embodiments and comparative example The surface state of the particle of property substance is shown in following table 1.
<embodiment 1-3>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, when charging Cell voltage be 4.4V.When evaluating battery, discovery initial capacity is 9.4Wh, and capacity retention ratio is 80%.
<embodiment 1-4>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, when charging Cell voltage be 4.5V.When evaluating battery, discovery initial capacity is 10.0Wh, and capacity retention ratio is 61%.
<embodiment 1-5>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, it is to be deposited In lithium-cobalt composite oxide (LiCo0.98Al0.01Mg0.01O2) on coating material be ammonium dihydrogen phosphate (NH4H2PO4).It is evaluating When battery, discovery initial capacity is 9.1Wh, and capacity retention ratio is 80%.
<embodiment 1-6>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, it is to be deposited In lithium-cobalt composite oxide (LiCo0.98Al0.01Mg0.01O2) on coating material be lithium hexafluoro phosphate (LiPF6) and be burnt into temperature Degree is 700 DEG C.When evaluating battery, discovery initial capacity is 9.1Wh, and capacity retention ratio is 81%.
<embodiment 1-7>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, it is to be deposited In lithium-cobalt composite oxide (LiCo0.98Al0.01Mg0.01O2) on coating material be LiBF4 (LiBF4) and be burnt into temperature Degree is 700 DEG C.When evaluating battery, discovery initial capacity is 9.1Wh, and capacity retention ratio is 76%.
<embodiment 1-8>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, it is to be deposited In lithium-cobalt composite oxide (LiCo0.98Al0.01Mg0.01O2) on coating material be sulphur (S) and firing temperature be 700 DEG C. When evaluating battery, discovery initial capacity is 9.1Wh, and capacity retention ratio is 64%.
<embodiment 1-9>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, with Co: The atomic ratio of Li:P=98:0.5:0.5 mixes lithium-cobalt composite oxide (LiCo0.98Al0.01Mg0.01O2), lithium carbonate (Li2CO3) and diammonium hydrogen phosphate ((NH4)2HPO4).When evaluating battery, discovery initial capacity is 9.1Wh, and capacity is kept Rate is 80%.
<embodiment 1-10>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, with Co: The atomic ratio of Li:P=98:2.5:2.5 mixes lithium-cobalt composite oxide (LiCo0.98Al0.01Mg0.01O2), lithium carbonate (Li2CO3) and diammonium hydrogen phosphate ((NH4)2HPO4).When evaluating battery, discovery initial capacity is 8.9Wh, and capacity is kept Rate is 75%.
<embodiment 1-11>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, with Co: The atomic ratio of Li:P=98:5:5 mixes lithium-cobalt composite oxide (LiCo0.98Al0.01Mg0.01O2), lithium carbonate (Li2CO3) and Diammonium hydrogen phosphate ((NH4)2HPO4).When evaluating battery, discovery initial capacity is 8.2Wh, and capacity retention ratio is 69%.
<embodiment 1-12>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, lithium-cobalt The group of composite oxides becomes LiCo0.97Al0.01Mg0.02O2.When evaluating battery, discovery initial capacity is 9.0Wh, and is held Measuring conservation rate is 84%.
<embodiment 1-13>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, lithium-cobalt The group of composite oxides becomes LiCo0.95Al0.01Mg0.04O2.When evaluating battery, discovery initial capacity is 8.8Wh, and is held Measuring conservation rate is 82%.
<comparative example 1-1>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, it omits Lithium-cobalt composite oxide (LiCo0.98Al0.01Mg0.01O2) coating processing.When evaluating battery, discovery initial capacity is 9.2Wh, and capacity retention ratio is 31%.
<comparative example 1-2>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, it omits Lithium-cobalt composite oxide (LiCo0.98Al0.01Mg0.01O2) coating processing and cell voltage when charging be 4.2V.It is commenting When valence battery, discovery initial capacity is 8.1Wh, and capacity retention ratio is 71%.
<comparative example 1-3>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, it omits Lithium-cobalt composite oxide (LiCo0.98Al0.01Mg0.01O2) coating processing and cell voltage when charging be 4.4V.It is commenting When valence battery, discovery initial capacity is 9.5Wh, and capacity retention ratio is 25%.
<comparative example 1-4>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, lithium-cobalt The group of composite oxides becomes LiCoO2, to be deposited on lithium-cobalt composite oxide (LiCoO2) on coating material be lithium carbonate (Li2CO3), magnesium carbonate (MgCO3) and diammonium hydrogen phosphate ((NH4)2HPO4) mixture, and weigh and to mix lithium-cobalt compound Oxide (LiCoO2), lithium carbonate (Li2CO3), magnesium carbonate (MgCO3) and ammonium dihydrogen phosphate (NH4H2PO4), to obtain Co:Li: The atom ratio of Mg:P=100:1:1:1.When evaluating battery, discovery initial capacity is 9.1Wh, and capacity retention ratio is 32%.
<comparative example 1-5>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, lithium-cobalt The group of composite oxides becomes LiCoO2, to be deposited on lithium-cobalt composite oxide (LiCoO2) on coating material be aluminum fluoride (AlF3), and weigh and mix lithium-cobalt composite oxide (LiCoO2) and aluminum fluoride (AlF3), to obtain Co:Al=100:1 Atom ratio.When evaluating battery, discovery initial capacity is 9.1Wh, and capacity retention ratio is 30%.
<comparative example 1-6>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, lithium-cobalt The group of composite oxides becomes LiCoO2, to be deposited on lithium-cobalt composite oxide (LiCoO2) on coating material be aluminum phosphate (AlPO4), and weigh and mix lithium-cobalt composite oxide (LiCoO2) and aluminum phosphate (AlPO4), to obtain Co:Al=100: 1 atom ratio.When evaluating battery, discovery initial capacity is 9.1Wh, and capacity retention ratio is 25%.
<comparative example 1-7>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, lithium-cobalt The group of composite oxides becomes LiCoO2.When evaluating battery, discovery initial capacity is 9.1Wh, and capacity retention ratio is 20%.
<comparative example 1-8>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, lithium-cobalt The group of composite oxides becomes LiCoO2, to be deposited on lithium-cobalt composite oxide (LiCoO2) on coating material be lithium phosphate (Li3PO4), and weigh and mix lithium-cobalt composite oxide (LiCoO2) and lithium phosphate (Li3PO4), to obtain Co:P=100: 1 atom ratio.When evaluating battery, discovery initial capacity is 9.1Wh, and capacity retention ratio is 15%.
<comparative example 1-9>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with embodiment 1-1, the difference is that, with phosphorus Sour hydrogen diammonium ((NH4)2HPO4) coating processing after firing temperature in sintering process be 300 DEG C.When evaluating battery, hair Existing initial capacity is 8.6Wh, and capacity retention ratio is 35%.
Evaluation result is shown in following table 1.
From evaluation result as can be seen that making magnesium (Mg) with from composite oxide particle using positive active material wherein Inside be uniformly distributed to surface, and the mode of particle surface coats so that with the sulphur (S) of spread state, phosphorus (P) etc. Capacity retention ratio and good initial capacity may be implemented in embodiment.
On the other hand, wherein be not present coating material comparative example 1-1 into 1-3, due to battery charging capacity more Height, therefore capacity retention ratio is reduced more significantly.In addition, magnesium (Mg) in wherein oxide particle is unevenly distributed Comparative example 1-4 is into 1-6, even if can not keep high capacity conservation rate there are concentration gradient.Moreover, above-mentioned gold is not present In the case where belonging to element M 2, even if sulphur (S), phosphorus (P) etc. are dispersed on the surface of oxide particle, capacity retention ratio is also very low.
In embodiment 2-1 into 2-9, changes coating material and obtain with the coating on the surface of composite oxides The battery performance of the different positive electrode of material.
<embodiment 2-1>
Manufacture with embodiment 1-1 in identical non-aqueous electrolyte secondary battery, and with identical side in embodiment 1-1 Formula is evaluated using the charging voltage of 4.35V, the difference is that, instead of lithium carbonate and diammonium hydrogen phosphate, will have and pass through 10 μm of average diameter of laser scattering method measurement and the diammonium hydrogen phosphate ((NH of 190 DEG C of fusing point4)2HPO4) it is deposited on lithium-cobalt Composite oxides (LiCo0.98Al0.01Mg0.01O2) on.Initial capacity is 9.1Wh and capacity retention ratio is 85%.< embodiment 2-2>
Manufacture and identical non-aqueous electrolyte secondary battery in embodiment 2-1, the difference is that, will have and pass through laser 10 μm of average diameter of scattering method measurement and the ammonium sulfate ((NH of 513 DEG C of fusing point4)2HSO4) it is deposited on lithium-cobalt combined oxidation Object (LiCo0.98Al0.01Mg0.01O2) on.Initial capacity is 9.1Wh and capacity retention ratio is 87%.
<embodiment 2-3>
Manufacture and identical non-aqueous electrolyte secondary battery in embodiment 2-1, the difference is that, will have and pass through laser 30 μm of average diameter of scattering method measurement and the diammonium hydrogen phosphate ((NH of 190 DEG C of fusing point4)2HPO4) to be deposited on lithium-cobalt compound Oxide (LiCo0.98Al0.01Mg0.01O2) on.Initial capacity is 9.1Wh and capacity retention ratio is 80%.
<embodiment 2-4>
Manufacture and identical non-aqueous electrolyte secondary battery in embodiment 2-1, the difference is that, coating lithium-cobalt is compound Oxide (LiNi0.79Co0.19Al0.01Mg0.01O2).Initial capacity is 10.9Wh and capacity retention ratio is 81%.
<embodiment 2-5>
Manufacture and identical non-aqueous electrolyte secondary battery in embodiment 2-1, the difference is that, coating lithium-cobalt is compound Oxide (LiNi0.49Co0.19Mn0.29Al0.01Mg0.01O2).Initial capacity is 9.5Wh and capacity retention ratio is 80%.
<embodiment 2-6>
Manufacture and identical non-aqueous electrolyte secondary battery in embodiment 2-1, the difference is that, will have and pass through laser 10 μm of average diameter of scattering method measurement and the phosphoric acid (H of 43 DEG C of fusing point3PO4) it is deposited on lithium-cobalt composite oxide (LiCo0.98Al0.01Mg0.01O2) on.Initial capacity is 9.1Wh and capacity retention ratio is 53%.
<embodiment 2-7>
Manufacture and identical non-aqueous electrolyte secondary battery in embodiment 2-1, the difference is that, will have and pass through laser 10 μm of average diameter of scattering method measurement and the ferric sulfate (Fe of 480 DEG C of fusing point2(SO4)3) it is deposited on lithium-cobalt combined oxidation Object (LiCo0.98Al0.01Mg0.01O2) on.Initial capacity is 8.9Wh and capacity retention ratio is 80%.
<embodiment 2-8>
Manufacture and identical non-aqueous electrolyte secondary battery in embodiment 2-1, the difference is that, will have and pass through laser 100 μm of average diameter of scattering method measurement and the diammonium hydrogen phosphate ((NH of 190 DEG C of fusing point4)2HPO4) to be deposited on lithium-cobalt multiple Close oxide (LiCo0.98Al0.01Mg0.01O2) on.Initial capacity is 9.1Wh and capacity retention ratio is 58%.
<embodiment 2-9>
Manufacture and identical non-aqueous electrolyte secondary battery in embodiment 2-1, the difference is that, will have and pass through laser 100 μm of average diameter of scattering method measurement and the diammonium hydrogen phosphate ((NH of 837 DEG C of fusing point4)2HPO4) to be deposited on lithium-cobalt multiple Close oxide (LiCo0.98Al0.01Mg0.01O2) on.Initial capacity is 9.0Wh and capacity retention ratio is 60%.
Evaluation result is shown in following table 2.In table 2, further it is shown that the result of the comparative example 1-1 for reference.
From evaluation result as can be seen that wherein include phosphorus P or fluorine F compound or pyrolysis compound have 80 DEG C to Capacity retention ratio may be implemented into 2-5 in the embodiment 2-1 of 600 DEG C of fusing point.It assume that when being burnt at 900 DEG C, wrap The compound or pyrolysis compound of phosphorous P or fluorine F becomes liquid and is evenly coated with the surface of composite oxides.In these realities It applies in example, because ammonium is evaporated and is not retained in active material, initial capacity keeps very high.
In embodiment 2-4 and 2-5, make when using lithium-nickel-cobalt composite oxides or lithium-nickel-cobalt manganese composite oxide For positive active material center material when, can be had so that the concentration of metallic element M2 is from composite oxide particle Center is to the increased concentration gradient in surface and the positive active material of good capacity retention ratio.
About embodiment 2-6, capacity retention ratio is improved, but is not very big due to improving caused by coating.Cause For in mechanochemistry treatment process phosphoric acid dissolve and coat no embodiment 2-1 those of into 2-5 effectively.This is because Caused by temperature of the fusing point of phosphoric acid lower than mechanochemistry processing.
About embodiment 2-7, in the range of falling in 70 DEG C to 600 DEG C due to the fusing point of compound, coating preferably, but divides The substance of solution is retained on positive electrode surface, and because the impurity is helpless to charge or discharge reaction, initial discharge capacity Slightly reduce.
In embodiment 2-8, because the diameter of coating material is too big, coating material is not mixed with composite oxides well It closes.Therefore, capacity retention ratio improves, but is not very big due to improving caused by coating.Because the fusing point of coating material is 837 DEG C, higher than 600 DEG C and close to firing temperature, this causes to melt in coating material and preferably coats the composite oxides Before, coating material is reacted with the region of composite oxides, and is destroyed well applied.
In embodiment 3-1 to 3-14 and comparative example 3-1 into 3-14, change ratio d and molar fraction ratio r and really Determine battery behavior.
In these embodiments, ratio d and molar fraction ratio r are obtained as follows.
[ratio d and molar fraction ratio r]
Lithium-transition metal that the buffer solvent for being prepared into pH 5.1 with citric acid and sodium citrate is added to 0.2g is compound In oxide.Stir mixture and per minute with 0.2 μm of filter filtered sample.Include major shift in each sample The quality or volumetric concentration of metal M1 (i.e. Co) and the quality or volumetric concentration of metallic element M2 (i.e. Mg, Mn, Ni) pass through ICP- AES: inductively coupled plasma atomic emission spectrometry [HORIBA JY238 ULTRACE] is measured to be dissolved in The quality of M1 and M2 in the buffer solvent of 10mL.Using this as a result, calculating the amount [mol] of M1 and M2.According to formula (I) and (II) ratio d and molar fraction ratio r are determined.
Ratio d (%)=[(quality of primary transition metal M1)+(quality of metallic element M2)]/(matter of particle entirety Amount) (I)
Molar fraction r=(amount of substance of metallic element M2)/[(amount of substance of primary transition metal M1)+(metallic element M2 Amount of substance)] (II)
For capacity retention ratio and high temperature dwell sustainability, the coating including M2 be it is most effective, wherein ratio d is full Foot 0.20≤r≤0.80, that is, from 10nm to the 100nm depth on surface.In the examples below, molar fraction ratio r with than Rate d changes and has detected the battery performance of each battery in the range of 0.20≤r≤0.80.
In the examples below, the distribution of metallic element M2 and element X are determined as follows.
[distribution of metallic element M2 and element X]
Mg is checked by SEM/EDX, to confirm whether Mg is evenly distributed on the surface of particle or whether P is dispersed in On surface.Particle is cut, and measures the company for observing Mg concentration along the Elemental redistribution of diameter by Auger electron spectroscopy Continuous variation.
<embodiment 3-1>
Positive active material is prepared as follows.
By the precursor for being used to be burnt into a manner of identical with embodiment 1-1 with the rate of 3 DEG C/min to heating up, and And 3 hours are maintained at 900 DEG C, then Slow cooling, to obtain lithium-compound transition metal oxide.Lithium-the transition metal is multiple Closing oxide has the magnesium (Mg) being evenly distributed on the surface of lithium-cobalt composite oxide particle.In addition, the concentration of magnesium (Mg) exists The surface of particle is higher than the inside in particle, and lithium phosphate (Li3PO4) spread at the surface of the particles.
In addition, confirming the surface concentration gradient of magnesium Mg in detail.Under ratio d=0.02%, 0.05% mole point Percentage r is respectively 0.32,0.30.Molar fraction ratio r under ratio d=0.01%, 0.10% is respectively 0.46, 0.25。
Lithium-compound transition metal oxide surface state is confirmed by observing the powder of acquisition at SEM/EDX.? Observe lithium-compound transition metal oxide surface when, it was confirmed that magnesium (Mg) at the surface of the particles be uniformly distributed with phosphorus Distribution on grain surface.Powder X-ray diffraction pattern measurement is carried out to powder by using CuK α, in addition to being equivalent to stratiform The LiCoO of rock salt structure2Diffraction maximum except, have also demonstrated and be equivalent to Li3PO4Diffraction maximum.In addition, the concentration of magnesium is by cutting Lithium-compound transition metal oxide section is opened, and is confirmed by the Elemental redistribution of auger electron spectrometry radial direction.It is surveying After measuring the Elemental redistribution in lithium-compound transition metal oxide section, the concentration of magnesium is proved to be inside from the surface of particle Portion's consecutive variations.
As a positive electrode active material by using the lithium-compound transition metal oxide as above obtained, according to embodiment Identical method has manufactured non-aqueous electrolyte secondary battery in 1-1.
The evaluation of initial capacity, capacity retention ratio and High temperature storage performance is carried out to battery.It is following to determine high temperature dwell sustainability Energy.
In the environment of 45 DEG C of ambient temperature to battery manufactured as above with the charging current of 1.5A charge until 4.35V charging voltage.It is discharged immediately with the discharge current of 2.0A battery later, and when cell voltage is reduced to Terminate to discharge when 3.0V.Then High temperature storage was carried out to battery in 300 hours by being retained in the environment of 60 DEG C of ambient temperature. Later, the discharge capacity after High temperature storage is measured by discharging with 0.2C.Electric discharge after being saved using initial capacity and heat preservation Capacity obtains high temperature capacity retention ratio according to the following formula, that is, high temperature dwell sustainability.High temperature capacity retention ratio [%]=(heat preservation saves Discharge capacity/initial capacity afterwards) × 100.
<embodiment 3-2>
Prepare non-aqueous electrolyte secondary battery in a manner of identical with embodiment 3-1, and with phase in embodiment 3-1 Same mode carries out the evaluation of initial capacity, capacity retention ratio and High temperature storage retention property, the difference is that, charging voltage For 4.2V.
<embodiment 3-3>
Prepare non-aqueous electrolyte secondary battery in a manner of identical with embodiment 3-1, and with phase in embodiment 3-1 Same mode carries out the evaluation of initial capacity, capacity retention ratio and High temperature storage retention property, the difference is that, charging voltage For 4.5V.
<embodiment 3-4>
Positive active material is prepared in a manner of identical with embodiment 3-1, the difference is that, the temperature of the second firing Degree is set as 950 DEG C, and the time of the second firing is 30 minutes.Molar fraction ratio under ratio d=0.02%, 0.05% Rate r is respectively 0.22,0.21.Molar fraction ratio r under ratio d=0.01%, 0.10% is respectively 0.38,0.16.With Non-aqueous electrolyte secondary battery is prepared with mode identical in embodiment 3-1, and in a manner of identical with embodiment 3-1 into The evaluation of row initial capacity, capacity retention ratio and High temperature storage retention property, the difference is that, charging voltage 4.5V.
<embodiment 3-5>
Positive active material is prepared in a manner of identical with embodiment 3-1, the difference is that, as answering for substrate Conjunction oxide is LiCo0.95Al0.01Mg0.04O2.Molar fraction ratio r under ratio d=0.02%, 0.05% is respectively 0.73,0.52.Molar fraction ratio r under ratio d=0.01%, 0.10% is respectively 0.86,0.44.With with embodiment 3- Identical mode is in 1 to prepare non-aqueous electrolyte secondary battery, and is initially held in a manner of identical with embodiment 3-1 The evaluation of amount, capacity retention ratio and High temperature storage retention property.
<embodiment 3-6>
Positive active material is prepared in a manner of identical with embodiment 3-1, the difference is that, as answering for substrate Conjunction oxide is LiCo0.97Al0.01Mg0.02O2.Molar fraction ratio r under ratio d=0.02%, 0.05% is respectively 0.31,0.31.Molar fraction ratio r under ratio d=0.01%, 0.10% is respectively 0.56,0.25.With with embodiment 3- Identical mode is in 1 to prepare non-aqueous electrolyte secondary battery, and is initially held in a manner of identical with embodiment 3-1 The evaluation of amount, capacity retention ratio and High temperature storage retention property.
<embodiment 3-7>
Positive active material is prepared in a manner of identical with embodiment 3-1, the difference is that, as answering for substrate Conjunction oxide is LiCoO3And with lithium carbonate Li2CO3, magnesium carbonate MgCO3, ammonium dihydrogen phosphate NH4H2PO4Shown in table 3 and table 4 Ratio mixing.Molar fraction ratio r under ratio d=0.02%, 0.05% is respectively 0.46,0.40.In ratio d= 0.01%, the molar fraction ratio r under 0.10% is respectively 0.55,0.44.It is prepared in a manner of identical with embodiment 3-1 Non-aqueous electrolyte secondary battery, and initial capacity, capacity retention ratio and high temperature dwell are carried out in a manner of identical with embodiment 3-1 Deposit the evaluation of retention property.
<embodiment 3-8>
Positive active material is prepared in a manner of identical with embodiment 3-1, the difference is that, use LiCoO2Make For the lithium-cobalt composite oxide for substrate, and coated with the coating material of nickel hydroxide and manganese phosphate.In coating, system Standby and mixing material makes the molar fraction ratio r (Ni+Mn/Ni+Mn+Co) under ratio d=0.02%, 0.05% respectively 0.35,0.34, and the molar fraction ratio r under ratio d=0.01%, 0.10% is respectively 0.56,0.25.With with implementation Identical mode is in example 3-1 to prepare non-aqueous electrolyte secondary battery, and is carried out initially in a manner of identical with embodiment 3-1 The evaluation of capacity, capacity retention ratio and High temperature storage characteristic.
<comparative example 3-1>
Using not having cated composite oxides LiCo0.98Al0.01Mg0.01O2As a positive electrode active material.In ratio d= 0.02%, the molar fraction ratio r under 0.05% is respectively 0.01,0.01.Mole under ratio d=0.01%, 0.10% Fractional ratio r is respectively 0.01,0.01.Non-aqueous electrolyte secondary battery is prepared in a manner of identical with embodiment 3-1, and The evaluation of initial capacity, capacity retention ratio and High temperature storage characteristic is carried out in a manner of identical with embodiment 3-1.
<comparative example 3-2>
Positive active material is prepared in a manner of identical with embodiment 3-1, the difference is that, LiCoO2For making For the lithium-cobalt composite oxide of substrate, and with lithium carbonate Li2CO3, magnesium carbonate MgCO3With ammonium dihydrogen phosphate NH4H2PO4With Co: The molar ratio of Li:Mg:P=100:1:0.5:1 mixes.Molar fraction ratio r point under ratio d=0.02%, 0.05% It Wei 0.18,0.10.Molar fraction ratio r under ratio d=0.01%, 0.10% is respectively 0.25,0.08.With with implementation Identical mode is in example 3-1 to prepare non-aqueous electrolyte secondary battery, and is carried out initially in a manner of identical with embodiment 3-1 The evaluation of capacity, capacity retention ratio and High temperature storage characteristic.
<comparative example 3-3>
Positive active material is prepared in a manner of identical with embodiment 3-1, the difference is that, lithium-cobalt composite oxygen Compound LiCo0.98Al0.01Mg0.01O2, lithium carbonate Li2CO3, magnesium carbonate MgCO3With ammonium dihydrogen phosphate NH4H2PO4With Co:Li:Mg:P The molar ratio of=100:1:1:4 mixes.Molar fraction ratio r under ratio d=0.02%, 0.05% is respectively 0.82, 0.83.Molar fraction ratio r under ratio d=0.01%, 0.10% is respectively 0.80,0.85.With with phase in embodiment 3-1 Same mode carries out initial capacity, capacity in a manner of identical with embodiment 3-1 to prepare non-aqueous electrolyte secondary battery The evaluation of conservation rate and High temperature storage characteristic.
<comparative example 3-4>
Positive active material is prepared in a manner of identical with embodiment 3-1, the difference is that, the temperature of the second firing Degree is set as 950 DEG C, and the time of the second firing is 30 minutes.Molar fraction ratio under ratio d=0.02%, 0.05% Rate r is respectively 0.22,0.21.Molar fraction ratio r under ratio d=0.01%, 0.10% is respectively 0.38,0.16.With Non-aqueous electrolyte secondary battery is prepared with mode identical in embodiment 3-1, and in a manner of identical with embodiment 3-1 into The evaluation of row initial capacity, capacity retention ratio and High temperature storage characteristic.
<comparative example 3-5>
Positive active material is prepared in a manner of identical with embodiment 3-1, the difference is that, LiCo0.95Al0.01Mg0.04O2For the lithium-cobalt composite oxide as substrate.Rubbing under ratio d=0.02%, 0.05% Your fractional ratio r is respectively 0.73,0.52.Molar fraction ratio r under ratio d=0.01%, 0.10% is respectively 0.86, 0.44.Non-aqueous electrolyte secondary battery is prepared, and in a manner of identical with embodiment 3-1 with identical with embodiment 3-1 Mode carry out the evaluation of initial capacity, capacity retention ratio and High temperature storage characteristic.
<comparative example 3-6>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with comparative example 3-5.With identical with embodiment 3-1 Mode carry out the evaluation of initial capacity, capacity retention ratio and High temperature storage characteristic to battery, the difference is that, when charging Cell voltage is 4.2V.
<comparative example 3-7>
Non-aqueous electrolyte secondary battery is manufactured in a manner of identical with comparative example 3-5.With identical with embodiment 3-1 Mode carry out the evaluation of initial capacity, capacity retention ratio and High temperature storage characteristic to battery, the difference is that, when charging Cell voltage is 4.5V.
<comparative example 3-8>
Positive active material is prepared in a manner of identical with embodiment 3-1, the difference is that, omit the second firing Step.Molar fraction ratio r under ratio d=0.02%, 0.05% is respectively 0.80,0.81.Ratio d=0.01%, Molar fraction ratio r under 0.10% is respectively 0.82,0.79.Non- water power is manufactured in a manner of identical with embodiment 3-1 Electrolitc secondary cell is solved, and carries out initial capacity, capacity retention ratio and High temperature storage characteristic in a manner of identical with embodiment 3-1 Evaluation.
<comparative example 3-9>
Positive active material is prepared in a manner of identical with embodiment 3-1, the difference is that, carry out mechanochemistry Processing 15 minutes.Molar fraction ratio r under ratio d=0.02%, 0.05% is respectively 0.21,0.16.In ratio d= 0.01%, the molar fraction ratio r under 0.10% is respectively 0.31,0.14.It is manufactured in a manner of identical with embodiment 3-1 Non-aqueous electrolyte secondary battery, and initial capacity, capacity retention ratio and high temperature dwell are carried out in a manner of identical with embodiment 3-1 Deposit the evaluation of characteristic.
<comparative example 3-10>
Positive active material is prepared in a manner of identical with embodiment 3-1, the difference is that, LiCoO2With effect It is coated in the lithium-cobalt composite oxide of substrate, and with the coating material of nickel hydroxide and manganese phosphate.In coating, preparation is simultaneously Mixing material makes molar ratio=1:1:1 of the Ni:Co:Mn in entire positive active material particle, and in ratio d= 0.02%, the molar fraction ratio r (Ni+Mn/Ni+Mn+Co) under 0.05% is respectively 0.25,0.17, and in ratio d= 0.01%, the molar fraction ratio r under 0.10% is respectively 0.30,0.15.It is manufactured in a manner of identical with embodiment 3-1 Non-aqueous electrolyte secondary battery, and initial capacity, capacity retention ratio and high temperature dwell are carried out in a manner of identical with embodiment 3-1 Deposit the evaluation of characteristic.
The positive active material of the non-aqueous electrolyte secondary battery of embodiment 3-1 to 3-8 and comparative example 3-1 to 3-10 Structure and evaluation result are shown in following table 3 and table 4.
From evaluation result as can be seen that may be implemented into 3-8 by the decline of control initial capacity in embodiment 3-1 good Good capacity retention ratio and High temperature storage characteristic.On the other hand, there is no these effects into 3-10 in comparative example 3-1.
The ratio d of the positive active material of embodiment 3-1 to 3-8 meets the molar fraction under 0.02%≤d≤0.05% Ratio r is fallen in range 0.20≤r≤0.80.Also, they, which are showed, meets the model of 0.02%≤d≤0.05% in ratio d In enclosing, the trend that molar ratio r reduces from surface to depth direction.
When certain depth range (meets 0.02%≤d≤0.05% from a surface to the ratio d (%) of 10nm to 100nm) When, the molar fraction ratio r of the positive active material of comparative example 3-1 to 3-2,3-4,3-9 to 3-10 is constant or along depth Direction reduces.But molar fraction ratio r is not fallen in the range of 0.20≤r≤0.80.
The molar fraction ratio r of comparative example 3-1 is because without using coating not in the range of 0.20≤r≤0.80 Material.The molar fraction ratio r of comparative example 3-2 is because of substrate and coating material not in the range of 0.20≤r≤0.80 Mixed volume is not appropriate.The molar fraction ratio r of comparative example 3-4 is because the not in the range of 0.20≤r≤0.80 Two firing temperatures are 750 DEG C.The molar fraction ratio r of comparative example 3-9 is because of machine not in the range of 0.20≤r≤0.80 The tool chemically treated time is 15 minutes, too short compared with embodiment 3-1.The molar fraction ratio r of comparative example 3-10 does not exist It is because the mixed volume of substrate and coating material is not appropriate in the range of 0.20≤r≤0.80.
When ratio d (%) meets 0.02%≤d≤0.05%, mole of the positive active material of comparative example 3-3 and 3-8 Fractional ratio r is fallen in outside the range of 0.20≤r≤0.80.And they show such trend: certain depth range (i.e. From the 10nm to 100nm on surface) in the range of ratio d (%) meets 0.02%≤d≤0.05%, molar ratio r is from table Face increases to depth direction.
The molar fraction ratio r of the positive active material of comparative example 3-3 is fallen in outside the range of 0.20≤r≤0.80, be because It is not appropriate for the mixed volume of substrate and coating material.The molar fraction ratio r of the positive active material of comparative example 3-8 is fallen It is because without carrying out the second firing processing outside the range of 0.20≤r≤0.80.
The molar fraction ratio r of the positive active material of comparative example 3-5 to 3-7 is fallen in the range of 0.20≤r≤0.80. But they show such trend: when certain depth range (expires into 100nm) at ratio d (%) from a surface to 10nm In the range of foot 0.02%≤d≤0.05%, molar fraction ratio r increases from surface to depth direction.
The molar fraction ratio r of the positive active material of comparative example 3-5 to 3-7 increases, and is because of the second firing processing Temperature is 850 DEG C.
Go out as shown above, in the model for meeting 0.02%≤d≤0.05% in ratio d into certain depth range from surface In enclosing, when molar fraction ratio r is fallen in the range of 0.20≤r≤0.80, by inhibiting the decline of initial capacity may be implemented Good capacity retention ratio and High temperature storage characteristic.
About the preparation method of positive active material, with embodiment 3-1 into 3-6, metallic element M2 is preferably from base Material leads to surface.Preparation method makes simple process, and the material prepared has distribution more evenly at surface, and very Structure is kept well, which improve capacity retention ratios and High temperature storage characteristic.
It can be seen that the anode with the ratio d outside the range of 0.02%≤d≤0.05% from the evaluation result in table 4 Active material is different surely to improve capacity retention ratio and High temperature storage characteristic, even if molar fraction ratio r is in 0.20≤r≤0.80 In the range of.
The analysis method on the surface about positive active material, be used for so far XPS (x-ray photoelectron spectroscopy) and TOF-SIMS (time of flight secondary ion massspectrometry).Table 3 shows the molar fraction ratio r of measurement, wherein passing through these methods The ratio d corresponding with the depth bounds along depth direction of measurement is 0.010%, corresponds to the area from a few nm depth on surface Domain, and be wherein 0.100% by the ratio d for corresponding to the depth bounds along depth direction that this method measures, it corresponds to In the region greater than 100nm depth from surface.
<embodiment 3-9>
The non-aqueous electrolyte secondary battery as manufactured in embodiment 3-4 is dismantled, and peels positive electrode collector off from electrode, By being immersed in NMP from positive active material except no-bonder, conductive agent is burnt up to obtain positive active material.In ratio Molar fraction ratio r under d=0.02% and 0.05% is respectively 0.29 and 0.22.
<embodiment 3-10>
The non-aqueous electrolyte secondary battery as manufactured in embodiment 3-5 is dismantled, and peels positive electrode collector off from electrode, By being immersed in NMP from positive active material except no-bonder, conductive agent is burnt up to obtain positive active material.In ratio Molar fraction ratio r under d=0.02% and 0.05% is respectively 0.79 and 0.53.
The structure and evaluation result of the positive active material of the non-aqueous electrolyte secondary battery of embodiment 3-9 and 3-10 are shown in In the following table 5.
Table 5
Annotation:
U.: uniformly, nu.: uneven, pr.: existing, ab.: being not present, int.: spreading
Table 5 is shown when removing positive active material from non-aqueous electrolyte secondary battery, ratio d 0.02% to Molar fraction ratio r under 0.05% is fallen in the range of 0.20 < r < 0.80.
<embodiment 3-11>
Positive active material is prepared as follows.
With the atom ratio of Co:P=99:1 mixing with embodiment 3-1 it is identical have measured by laser scattering method The lithium of 13 μm of average diameters-cobalt/cobalt oxide LiCo0.98Al0.01Mg0.01O2(pass through with by jet mill comminution at 6 μm of average diameters Laser scattering method measurement) ammonium dihydrogen phosphate NH4H2PO4。
It is handled mixture 1 hour by mechanochemistry device, to deposit biphosphate on lithium-cobalt/cobalt oxide surface Ammonium, thus the precursor before being fired.It is heated up with the rate of 3 DEG C/min to the precursor, and holding 3 is small at 900 DEG C When, then Slow cooling, to obtain lithium-compound transition metal oxide.Lithium-the compound transition metal oxide has equably The magnesium (Mg) being distributed on lithium-compound transition metal oxide particle surface.In addition, the concentration of magnesium (Mg) is in particle surface ratio Want high in the inside of particle, and lithium phosphate (Li3PO4) spread at the surface of the particles.
Incidentally, the surface concentration gradient of magnesium Mg is confirmed in detail.Ratio d=0.01%, 0.015%, 0.02%, the molar fraction ratio r at 0.05% is respectively 0.82,0.73,0.62 and 0.40.
The surface state of the material of acquisition is confirmed by observing the powder of acquisition at SEM/EDX.In observation, it was demonstrated that The distribution being uniformly distributed with phosphorus at the surface of the particles of magnesium (Mg) at the surface of the particles.Powder is carried out to particle by using CuK α The measurement of last X-ray diffraction pattern, in addition to being equivalent to the LiCoO with layered rock salt structure2Diffraction maximum except, have also demonstrated It is equivalent to Li3PO4Diffraction maximum.In addition, the concentration of magnesium, which passes through, cuts lithium-compound transition metal oxide section, and pass through Russia Auger electron spectroscopy measures radial Elemental redistribution to confirm.Measure particle section in Elemental redistribution when, the concentration quilt of magnesium It turns out to be from the surface of particle towards internal consecutive variations.
As a positive electrode active material by using the lithium as above obtained-compound transition metal oxide particle, with implementation Identical mode has manufactured non-aqueous electrolyte secondary battery in example 3-1, and to battery in a manner of identical with embodiment 3-1 The evaluation of initial capacity, capacity retention ratio and High temperature storage characteristic is carried out.
<embodiment 3-12>
Positive active material is prepared in a manner of identical with embodiment 3-11, the difference is that, with Co:P= The atom ratio mixing of 98.8:1.2 has lithium-cobalt/cobalt oxide of the 6 μm of average diameters measured by laser scattering method LiCo0.98Al0.01Mg0.01O2With the biphosphate by jet mill comminution at 6 μm of average diameters (being measured by laser scattering method) Ammonium NH4H2PO4。
Incidentally, the surface concentration gradient of magnesium Mg is confirmed in detail.Ratio d=0.01%, 0.015%, 0.02%, the molar fraction ratio r at 0.05% is respectively 0.92,0.85,0.80 and 0.65.
As a positive electrode active material by using the lithium as above obtained-compound transition metal oxide particle, with implementation Identical mode has manufactured non-aqueous electrolyte secondary battery in example 1-1.And to electricity in a manner of identical with embodiment 3-11 Pond has carried out the evaluation of initial capacity, capacity retention ratio and High temperature storage characteristic.
<embodiment 3-13>
There is lithium-cobalt of 6 μm of average diameters (being measured by laser scattering method) with the atom ratio mixing of Co:S=99:1 Oxide LiCo0.98Al0.01Mg0.01O2With the sulphur by jet mill comminution at 3 μm of average diameters (being measured by laser scattering method) Sour ammonium (NH4)2SO4.It is handled mixture 30 minutes by planetary-type mixer, so that ammonium sulfate precipitation is in lithium-cobalt/cobalt oxide table On face.Other than the above process, positive active material is prepared in a manner of identical with embodiment 3-11.In ratio d= 0.01%, the molar fraction ratio r at 0.015%, 0.02%, 0.05% is respectively 0.80,0.71,0.58 and 0.38.
As a positive electrode active material by using the lithium as above obtained-compound transition metal oxide particle, with implementation Identical mode has manufactured non-aqueous electrolyte secondary battery in example 3-11.And to electricity in a manner of identical with embodiment 3-11 Pond has carried out the evaluation of initial capacity, capacity retention ratio and High temperature storage characteristic.
<embodiment 3-14>
Positive active material is prepared in a manner of identical with embodiment 3-11, the difference is that, with Co:P=99: 1 atom ratio mixed phosphate ammonium dihydrogen NH4H2PO4With the lithium cobalt with the 100 μm of average diameters measured by laser scattering method Oxide.
Incidentally, the surface concentration gradient of magnesium Mg is confirmed in detail.Ratio d=0.01%, 0.015%, 0.02%, the molar fraction ratio r at 0.05% is respectively 0.62,0.53,0.44 and 0.25.
As a positive electrode active material by using the lithium as above obtained-compound transition metal oxide particle, with implementation Identical mode has manufactured non-aqueous electrolyte secondary battery in example 3-11.And to electricity in a manner of identical with embodiment 3-11 Pond has carried out the evaluation of initial capacity, capacity retention ratio and High temperature storage characteristic.
<comparative example 3-11>
Positive active material is prepared in a manner of identical with embodiment 3-11, the difference is that, with Co:P=95: 5 atom ratio mixed phosphate ammonium dihydrogen NH4H2PO4With the lithium cobalt oxide with the 6 μm of average diameters measured by laser scattering method Compound.
Incidentally, the surface concentration gradient of magnesium Mg is confirmed in detail.Ratio d=0.01%, 0.015%, 0.02%, the molar fraction ratio r at 0.05% is respectively 0.98,0.95,0.92 and 0.85.
As a positive electrode active material by using the lithium as above obtained-compound transition metal oxide particle, with implementation Identical mode has manufactured non-aqueous electrolyte secondary battery in example 3-11.And to electricity in a manner of identical with embodiment 3-11 Pond has carried out the evaluation of initial capacity, capacity retention ratio and High temperature storage characteristic.
<comparative example 3-12>
Positive active material is prepared in a manner of identical with embodiment 3-11, the difference is that, with Co:S=99: 1 atom ratio mixing ammonium sulfate (NH4)2SO4With the lithium cobalt oxidation with the 6 μm of average diameters measured by laser scattering method Object.
Incidentally, the surface concentration gradient of magnesium Mg is confirmed in detail.Ratio d=0.01%, 0.015%, 0.02%, the molar fraction ratio r at 0.05% is respectively 0.33,0.25,0.20 and 0.15.
As a positive electrode active material by using the lithium as above obtained-compound transition metal oxide particle, with implementation Identical mode has manufactured non-aqueous electrolyte secondary battery in example 3-11.And to electricity in a manner of identical with embodiment 3-11 Pond has carried out the evaluation of initial capacity, capacity retention ratio and High temperature storage characteristic.
The positive active material of the non-aqueous electrolyte secondary battery of embodiment 3-11 to 3-14, comparative example 3-11 to 3-12 Structure and evaluation result are shown in following table 6.
The evaluation result shown in the table 6 can be seen that in the range of ratio d meets 0.02%≤d≤0.05%, implement The molar fraction ratio r of the positive active material of example 3-11,3-12,3-13 is fallen in range 0.20≤r≤0.80.And it is same When, in the range of ratio d meets 0.01%≤d < 0.02%, molar fraction ratio r is fallen in range 0.55≤r < 1.0.It is logical The decline for inhibiting their discharge capacity is crossed, these embodiments show to improve very big holding capacity rate and High temperature storage spy Property.
Ratio d meet 0.02%≤d≤0.05% in the range of, the positive active material of embodiment 3-14 mole point Percentage r is fallen in range 0.20≤r≤0.80.But ratio d meet 0.01%≤d < 0.02% in the range of, mole point Percentage r is not fallen in range 0.55≤r < 1.0.Embodiment 3-14 cannot obtain the holding capacity or high temperature dwell that height improves Sustainability.Because the average diameter of coating material ammonium dihydrogen phosphate is 100 μm, this upsets the good admixture of ammonium dihydrogen phosphate, To which good coating state cannot be obtained on the surface of the substrate.
Ratio d meet 0.01%≤d < 0.02% in the range of, the positive active material of comparative example 3-11 mole point Percentage r is fallen in range 0.55≤r < 1.0.But ratio d meet 0.02%≤d≤0.05% in the range of, mole point Percentage r is fallen in outside range 0.20≤r≤0.80.This is because too many coating material makes coating too thick, reduction is helped In the positive active material of charge-discharge capacities.Therefore, the initial discharge capacity very little of comparative example 3-11.
Ratio d meet 0.01%≤d < 0.02% in the range of, the positive active material of comparative example 3-12 mole point Percentage r is fallen in outside range 0.55≤r < 1.0.This is because coating material is not mixed and cannot be obtained with substrate well Good coating.Therefore, the good improvement for keeping capacity and High temperature storage characteristic cannot be obtained by comparing example 3-12.
Those skilled in the art should understand that can be made various changes according to design requirement and other factors, Combination, sub-portfolio and change, as long as they are in the range of appended claims or its equivalent.

Claims (8)

1. a kind of positive active material, including lithium-compound transition metal oxide, the lithium-compound transition metal oxide include Lithium, primary transition metal M1 and the metallic element M2 different from the primary transition metal M1, wherein
The metallic element M2 has the concentration gradient of the metallic element M2 from from the center of each particle to surface,
In the range of the ratio d (%) from surface to certain depth meets 0.020≤d≤0.050, molar fraction r (%) is full Sufficient formula 0.20≤r≤0.80,
Wherein, ratio d (%)=[(quality of the primary transition metal M1)+(quality of metallic element M2)]/(particle entirety Quality),
Molar fraction r=(amount of substance of metallic element M2)/[(amount of substance of primary transition metal M1)+(object of metallic element M2 Quality)],
Wherein, the primary transition metal M1 be selected from least one of nickel (Ni), cobalt (Co), manganese (Mn) and iron (Fe), And
Wherein, the metallic element M2 is selected from manganese (Mn), magnesium (Mg), aluminium (Al), nickel (Ni), boron (B), titanium (Ti), cobalt (Co) And at least one of iron (Fe) element,
Wherein, it is present on the surface selected from least one of sulphur S, phosphorus P and fluorine F element X with aggregated forms.
2. positive active material according to claim 1, wherein
In the range of the ratio d (%) from surface to certain depth meets 0.010≤d < 0.020, molar fraction r (%) meets Formula 0.55≤r < 1.00.
3. positive active material according to claim 1, wherein
From surface to the depth ratio d (%) meet 0.020≤d≤0.050 in the range of, molar fraction ratio r from The surface of the composite oxide particle reduces to center.
4. positive active material according to claim 2, wherein
In the range of the ratio d (%) from surface to the depth meets 0.010≤d < 0.020, molar fraction ratio r is from institute The surface for stating composite oxide particle reduces towards center.
5. positive active material according to claim 1, wherein
It by the lithium-compound transition metal oxide particle and include selected from least one of sulphur S, phosphorus P and fluorine F element Reaction between compound, the concentration of the metallic element M2 increase at the surface.
6. positive active material according to claim 5, wherein
The compound comprising lithium is existed simultaneously in the reaction process.
7. positive active material according to claim 5, wherein
Comprising selected from least one of sulphur S, phosphorus P and fluorine the F compound of element or the thermal decomposition product of the compound With 70 DEG C or more 600 DEG C of fusing points below.
8. positive active material according to claim 5, wherein
Comprising selected from least one of sulphur S, phosphorus P and fluorine the F compound of element or the thermal decomposition product of the compound With 30 μm of average diameters below.
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