JP2011003551A - Lithium transition metal based compound powder, its manufacturing method, spray drying object used as baking precursor of the powder, and positive electrode of lithium secondary battery and lithium secondary battery using the powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithium transition metal based compound powder, used as a positive electrode material of a lithium secondary battery, satisfying simultaneously improvement of load characteristics such as rate and output characteristics, low cost, high voltage resistance, and high safety.SOLUTION: In the lithium transition metal based compound powder used as a positive electrode material of a lithium secondary battery, a lithium transition metal based compound having functions capable of intercalating and disintercalating lithium ions is set up to be a primary component, and the lithium transition metal based compound is calcined after adding one or more kinds of additives for restraining particle growth and sintering at the time of calcination at a ratio of 0.01 mol% or more to less than 2 mol% against the total molal quantity of transition metal elements to a primary component material. In a manufacturing method for a lithium transition metal based compound powder, a lithium compound, one kind or more of transition metal compounds selected from V, Cr, Mn, Fe, Co, Ni, and Cu, and the additive for restraining particle growth and sintering at the time of calcination are pulverized in a liquid medium, slurry in which the above is uniformly dispersed is sprayed and dried, and the attained sprayed and dried powder is calcined.

Description

  The present invention relates to a lithium transition metal-based compound powder used as a positive electrode material for a lithium secondary battery, a method for producing the same, a spray-dried body as a firing precursor thereof, and a lithium secondary metal using the lithium transition metal-based compound powder. The present invention relates to a positive electrode for a secondary battery and a lithium secondary battery including the positive electrode for a lithium secondary battery.

  Lithium secondary batteries are excellent in energy density and output density, and are effective in reducing the size and weight. Therefore, the demand for power supplies for portable devices such as notebook computers, mobile phones, and handy video cameras is growing rapidly. ing. Lithium secondary batteries are also attracting attention as power sources for electric vehicles and power load leveling, and in recent years, demand for power sources for hybrid electric vehicles is rapidly expanding. In particular, in electric vehicle applications, it is necessary to be excellent in low cost, safety, life (particularly under high temperature) and load characteristics, and improvements in materials are desired.

Among the materials constituting the lithium secondary battery, as the positive electrode active material, a substance having a function capable of desorbing and inserting lithium ions can be used. There are various types of these positive electrode active material materials, each having its own characteristics. In addition, a common problem for improving performance is to improve load characteristics, and improvements in materials are strongly desired.
Furthermore, there is a demand for a material with a good performance balance that is excellent in low cost, safety, and life (particularly under high temperatures).

  Currently, lithium manganese composite oxides having a spinel structure, layered lithium nickel composite oxides, layered lithium cobalt composite oxides, and the like have been put into practical use as positive electrode active material materials for lithium secondary batteries. All of the lithium secondary batteries using these lithium-containing composite oxides have advantages and disadvantages in terms of characteristics. That is, a lithium manganese composite oxide having a spinel structure is inexpensive and relatively easy to synthesize, and is excellent in safety when used as a battery, but has a low capacity and inferior high-temperature characteristics (cycle and storage). Layered lithium-nickel composite oxides have high capacity and excellent high-temperature characteristics, but are difficult to synthesize, have inferior safety when used as batteries, and have drawbacks such as requiring careful storage. Layered lithium cobalt-based composite oxides are widely used as power sources for portable devices because they are easy to synthesize and have an excellent balance of battery performance. However, they are not sufficient in safety and costly. It is a drawback.

  Under these circumstances, lithium nickel manganese cobalt-based composite oxides with a layered structure have been proposed as promising candidates for active material materials that can overcome or reduce the shortcomings of these positive electrode active material materials and that are excellent in battery performance balance. Has been. Particularly, in recent years, demands for lowering costs, higher voltages, and increasing safety demands are promising as positive electrode active material materials that can meet any of the demands.

  However, the degree of cost reduction, higher voltage, and safety will vary depending on the composition ratio. Therefore, for further cost reduction, use with a higher upper limit voltage, and higher safety requirements. Therefore, it is necessary to select and use one having a limited composition range, such as increasing the manganese / nickel atomic ratio or reducing the cobalt ratio. However, a lithium secondary battery using a lithium nickel manganese cobalt based composite oxide having such a composition range as a positive electrode material has reduced load characteristics such as rate and output characteristics. It was necessary.

  Conventionally, the lithium nickel manganese cobalt-based composite oxide having a composition range in which the manganese / nickel atomic ratio and the cobalt ratio correspond to the values defined in the present invention are disclosed in Patent Documents 1 to 32 and Non-Patent Documents 1 to 73. ing.

  However, in Patent Documents 1 to 32 and Non-Patent Documents 1 to 73, there is no description focusing on additives that suppress the growth and sintering of active material particles during firing in the composition region defined by the present invention. The necessary conditions for improving the battery performance in the present invention are not satisfied, and it is extremely difficult to improve the battery performance indicated by the present invention only with these techniques.

  In addition, although there is no document describing “suppressing the growth and sintering of active material particles during firing” as indicated by the present invention, lithium nickel manganese cobalt based composite oxidation is aimed at improving the positive electrode active material. The following Patent Literatures 33 to 41 and Non-Patent Literature 74 are disclosed as known literatures in which compounds containing W, Mo, Nb, Ta, Re, etc. are added or replaced.

  Patent Document 33 and Patent Document 34 disclose that lithium, nickel-based composite oxide having a layered structure uses W, Mo, Ta, and Nb as substitution elements for transition metal sites. It is described that the thermal stability in the state is improved. However, since the composite oxide disclosed here has a composition mainly composed of Li and Ni, there is still a problem that an active material excellent in various battery characteristic balances cannot be obtained.

  Patent Document 35 discloses the use of lithium nickel manganese cobalt niobium-based composite oxide. However, the Mn molar ratio in the transition metal site is as low as 0.1 or less, and there is still a problem that an active material excellent in various battery characteristic balances cannot be obtained.

Patent Document 36 discloses the use of lithium nickel manganese cobalt-based composite oxide containing W and Mo, which makes it cheaper than LiCoO ₂ and has a high capacity and thermal stability in a charged state. Is described as being excellent. However, as a result of the excessive content of the additive metal elements (W, Mo) in the examples, there was still a problem that an active material excellent in various battery characteristic balances could not be obtained.

  Patent Document 37 discloses that in a lithium nickel manganese cobalt-based oxide having a layered structure, Ta, Nb is used as a substitution element for a transition metal site, and thus a usable voltage range is wide. It describes that the charge / discharge cycle durability is good and the capacity is high and the safety is high. However, since the firing temperature in Examples was as low as 900 ° C., there was a problem that crystals were not sufficiently developed and active materials having excellent balance of various battery characteristics could not be obtained.

  Patent Document 38 discloses an example in which W is substituted at a transition metal site in a lithium nickel manganese cobalt based composite oxide. However, since the Mn molar ratio in the transition metal site is as extremely small as 0.01 and the Ni molar ratio is as large as 0.8, it is still impossible to obtain an active material excellent in various battery characteristic balances. was there.

  Patent Document 39 discloses that a monoclinic lithium manganese nickel-based composite oxide in which transition metal sites are substituted with Nb, Mo, W is used as a positive electrode active material. It is described that a lithium secondary battery with high energy density, high voltage, and high reliability can be provided. However, according to the examples, since the firing temperature is as low as 950 ° C., the crystals are not sufficiently developed, and the molar ratio of the element is too high as 5 mol%, so that the active material still excellent in various battery characteristics balance There was a problem that could not get.

  Patent Document 40 discloses that a lithium-transition metal oxide particle having a layered structure has a compound having molybdenum and tungsten on at least the surface thereof, thereby providing excellent battery characteristics even in a more severe use environment. It is described that it has. However, according to the examples, the Co / (Ni + Co + Mn) molar ratio is too large as 0.33, and since the firing temperature is as low as 900 ° C., crystals do not develop sufficiently, and the various battery characteristics balance is still excellent. There was a problem that the active material could not be obtained.

  Patent Document 41 discloses using a lithium nickel manganese cobalt molybdenum based composite oxide having a layered structure. However, the composition of the examples had a problem that the Co / (Ni + Mn + Co) molar ratio was as high as 0.34 and the Co ratio was high, and it was still impossible to obtain an active material excellent in various battery characteristic balances.

Non-Patent Document 74 discloses a LiNi _1/3 Mn _1/3 Mo _1/3 O ₂ composite oxide having a layered structure. However, since the Mo content is too high, there is still a problem that an active material excellent in various battery characteristic balances cannot be obtained.

Japanese Patent No. 3110728 Japanese Patent No. 3571671 US6,680,143B2 Japanese Patent Laid-Open No. 11-307094 JP 2000-294242 A JP 2000-133262 A WO2002-040404 WO2002-073718 WO2002-086993 JP 2002-145623 A WO2003-044881 WO2003-048882 JP 2003-031219 A JP 2003-081639 A JP 2003-178756 A JP 2003-203633 A JP 2003-221236 A JP 2003-238165 A JP 2003-297354 A JP 2004-031091 A JP 2004006267 A Japanese Patent Application Laid-Open No. 2004-139853 JP 2004-265849 A JP 2004-281253 A JP 2004-31427 A Special table 2004-528691 JP-A-2005-150057 JP-A-2005-150093 JP 2005-150102 A JP 2005-187282 A JP 2003-051308 A JP-A-2005-123179 Japanese Patent No. 3088716 Japanese Patent No. 3362025 JP 2002-151071 A WO2002-041419 JP 2003-68298 A JP 2004-303673 A JP-A-2005-235628 JP-A-2005-251716 JP 2006-164934 0

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  That is, the object of the present invention is to improve load characteristics such as rate and output characteristics when used as a positive electrode material for a lithium secondary battery, and more preferably to reduce costs, increase voltage resistance, and increase safety. Lithium transition metal compound powder for lithium secondary battery positive electrode material that can be compatible, production method thereof, spray-dried body that is a firing precursor thereof, and lithium secondary battery using this lithium transition metal compound powder An object of the present invention is to provide a lithium secondary battery including the positive electrode and the positive electrode for the lithium secondary battery.

  In order to solve the problem of improving load characteristics such as rate and output characteristics, the inventors of the present invention have suppressed the grain growth and sintering while maintaining sufficiently high crystallinity at the stage of firing the active material. As a result of earnest study, considering that it is important to obtain particles, especially in layered lithium nickel manganese cobalt-based composite oxides, by adding a compound that suppresses grain growth during firing to the main component material, As a battery positive electrode material, we found that in addition to cost reduction, high voltage resistance, high safety, it is possible to obtain lithium transition metal-based compound powder capable of coexistence with improvement of load characteristics such as rate and output characteristics, The present invention has been completed.

  That is, the lithium transition metal-based compound powder for a lithium secondary battery positive electrode material of the present invention has a lithium transition metal-based compound having a function capable of inserting and removing lithium ions as a main component, Add at least one additive that suppresses grain growth and sintering during firing at a ratio of 0.01 mol% or more and less than 2 mol% with respect to the total molar amount of transition metal elements in the main component raw material And then fired (claim 1).

  Here, the additive for suppressing grain growth and sintering during firing is preferably an oxide containing at least one element selected from Mo, W, Nb, Ta, and Re. (Claim 2).

  Further, in the lithium transition metal-based compound powder of the present invention, the atomic ratio of the total of the additive elements to the total of the metal elements other than Li and the additive elements in the surface part of the primary particles is 5 of the atomic ratio of the whole particles. It is preferable that it is more than twice (claim 3).

Further, in the lithium transition metal-based compound powder of the present invention, the additive contains a metal element (hereinafter referred to as “additive element”), and the lithium is added to Li on the outermost surface of the particle and to the total of metal elements other than the additive element. the sum of the atomic ratio _{R 0} of the additive element, the ratio _R 0 _{/ R 10} of the atomic ratio _{R 10} of the depth 10nm from the particle surface, is preferably 3 times or more (claim 4).

  In the lithium transition metal compound powder of the present invention, the additive contains a metal element (hereinafter referred to as “additive element”), and the additive element has a non-linear concentration in the depth direction from the particle surface. It is preferable to have a continuous composition gradient structure that exists with a gradient (claim 5).

  The lithium transition metal-based compound powder of the present invention is ultrasonically dispersed for 5 minutes using a laser diffraction / scattering particle size distribution measuring apparatus with a refractive index of 1.24 and a particle diameter standard as a volume standard. It is preferable that the median diameter measured after the output of 30 W and the frequency of 22.5 kHz is 0.1 μm or more and less than 5 μm.

  In the lithium transition metal-based compound powder of the present invention, the average primary particle diameter is preferably 0.1 to 0.9 μm.

The lithium transition metal compound powder of the present invention preferably has a BET specific surface area of 1.5 to ⁵ m ² / g (Claim 8).

Further, the lithium transition metal based compound powder of the present invention has a mercury intrusion amount of 0.7 cm ³ / g or more, 1.5 cm at the time of pressurization from a pressure of 3.86 kPa to 413 MPa in a mercury intrusion curve by a mercury intrusion method. ³ / g or less (claim 9).

  The lithium transition metal-based compound powder of the present invention has at least one main peak having a peak top at a pore radius of 300 nm or more and 1000 nm or less in a pore distribution curve by a mercury intrusion method, and is fine. It is preferable not to have a sub-peak in which a peak top exists in a pore radius of 80 nm or more and less than 300 nm.

Further, the lithium transition metal based compound powder of the present invention has a pore volume of 0.4 cm ³ / pound according to a peak having a peak top at a pore radius of 300 nm or more and 1000 nm or less in a pore distribution curve by a mercury intrusion method. It is preferable that they are g or more and 1 cm < ³ > / g or less (Claim 11).

Further, the lithium transition metal-based compound powder of the present invention preferably has a bulk density of 0.5 g / cm ³ or more and 1.7 g / cm ³ or less (claim 12).

The lithium transition metal-based compound powder of the present invention preferably has a volume resistivity of 1 × 10 ³ Ω · cm or more and 1 × 10 ⁶ Ω · cm or less when compacted at a pressure of 40 MPa (claims) Item 13).

In addition, the lithium transition metal-based compound powder of the present invention is preferably mainly composed of a lithium nickel manganese cobalt-based composite oxide including a crystal structure belonging to a layered structure (claims). 14).

Furthermore, the lithium transition metal-based compound powder preferably has a composition represented by the following composition formula (I) (claim 15).
LiMO ₂ (I)
(However, in the above formula (I), M is an element composed of Li, Ni and Mn, or Li, Ni, Mn and Co. Mn / Ni molar ratio is 0.3 or more and 5 or less, (The Co / (Mn + Ni + Co) molar ratio is 0 or more and 0.30 or less, and the Li molar ratio in M is 0.001 or more and 0.2 or less.)

  The lithium transition metal compound powder of the present invention represented by the composition formula (I) is preferably fired at a firing temperature of 900 ° C. or higher in an oxygen-containing gas atmosphere. 16).

In addition, the lithium transition metal compound powder of the present invention whose composition is represented by the composition formula (I) has a C value of 0.005 wt% or more and 0 when the content carbon concentration is C (wt%). It is preferably 25% by weight or less (claim 17).

Furthermore, in the lithium transition metal-based compound powder of the present invention whose composition is represented by the formula (I), it is preferable that M is a composition represented by the following formula (II) (claim 18).
M = Li _{z / (2 + z)} {(Ni _{(1 + y) / 2} Mn _{(1-y) / 2} ) _1-x Co _x } _{2 / (2 + z)} (II)
(However, in the above formula (II),
0 ≦ x ≦ 0.1
−0.1 ≦ y ≦ 0.1,
(1-x) (0.05-0.98y) ≤z≤ (1-x) (0.20-0.88y)
It is. )

  Further, when the M of the composition formula (I) was measured by powder X-ray diffraction using CuKα rays for the lithium nickel manganese cobalt based composite oxide powder represented by the formula (II), the diffraction angle 2θ It is preferable that 0.01 ≦ FWHM (110) ≦ 0.2 when the half width of the (110) diffraction peak in the vicinity of 64.5 ° is FWHM (110) (claim 19).

Further, when M in the composition formula (I) was measured by powder X-ray diffraction using CuKα rays for the lithium nickel manganese cobalt composite oxide powder represented by the formula (II), a diffraction angle 2θ. In the (018) diffraction peak near 64 °, the (110) diffraction peak near 64.5 °, and the (113) diffraction peak near 68 ° on the higher angle side than the respective peak tops In the case of having no diffraction peak derived from a different phase or having a diffraction peak derived from a different phase, the integrated intensity ratio of the different phase peak to the diffraction peak of the original crystal phase is preferably in the following range, respectively.
0 ≦ I ₀₁₈ ^* / I ₀₁₈ ≦ 0.30
0 ≦ I ₁₁₀ ^* / I ₁₁₀ ≦ 0.25
0 ≦ I ₁₁₃ ^* / I ₁₁₃ ≦ 0.30
(Here, I ₀₁₈ , I ₁₁₀ , and I ₁₁₃ represent the integrated intensities of (018), (110), and (113) diffraction peaks, respectively, and I ₀₁₈ ^* , I ₁₁₀ ^* , and I ₁₁₃ ^* are (018 ), (110), (113) represents the integrated intensity of a diffraction peak derived from a different phase appearing at a higher angle side than the peak top of the diffraction peak.

  The method for producing a lithium transition metal-based compound powder for a lithium secondary battery positive electrode material according to the present invention is a method for producing such a lithium transition metal-based compound powder according to the present invention. , At least one transition metal compound selected from Mn, Fe, Co, Ni, and Cu and an additive that suppresses grain growth and sintering during firing in a liquid medium and uniformly A slurry preparation step for obtaining a slurry dispersed in the slurry, a spray drying step for spray drying the obtained slurry, and a firing step for firing the obtained spray dried powder (claim 21). .

  In the method for producing a lithium transition metal compound powder of the present invention, in the slurry preparation step, the lithium compound, the transition metal compound, and the additive are measured in a liquid medium by laser diffraction / scattering particle size distribution measurement. By means of an apparatus, the refractive index is set to 1.24, the particle diameter standard is the volume standard, and grinding is performed until the median diameter measured after 5 minutes of ultrasonic dispersion (output 30 W, frequency 22.5 kHz) is 0.4 μm or less. In the spray drying step, when the slurry viscosity during spray drying is V (cp), the slurry supply amount is S (L / min), and the gas supply amount is G (L / min), 50 cp ≦ V ≦ 4000 cp, It is preferable to perform spray drying under the condition of 500 ≦ G / S ≦ 10000.

  Further, in the method for producing a lithium transition metal compound powder of the present invention, the transition metal compound contains at least a nickel compound, a manganese compound and a cobalt compound, and in the firing step, the spray-dried powder is treated with an oxygen-containing gas atmosphere. It is preferable to bake at 970 ° C. or higher (claim 23).

  In the method for producing a lithium transition metal compound powder of the present invention, the lithium compound raw material used is preferably lithium carbonate (claim 24).

  Furthermore, the spray-dried body, which is a precursor of the lithium transition metal compound powder for a lithium secondary battery positive electrode material of the present invention, is at least selected from lithium compounds and V, Cr, Mn, Fe, Co, Ni, Cu. Spray dried product obtained by pulverizing one or more kinds of transition metal compounds and additives for suppressing grain growth and sintering during firing in a liquid medium and spray-drying a slurry in which these are uniformly dispersed With a laser diffraction / scattering type particle size distribution measuring device, the refractive index is set to 1.24, the particle diameter standard is the volume standard, and measurement is performed after 5 minutes of ultrasonic dispersion (output 30 W, frequency 22.5 kHz). The spray-dried product thus obtained has a median diameter of 0.1 μm or more and 4 μm or less (claim 25).

In addition, the spray-dried lithium transition metal compound of the present invention preferably has a BET specific surface area of 10 m ² / g or more and 100 m ² / g or less (Claim 26).

  The positive electrode for a lithium secondary battery of the present invention is characterized in that it has a positive electrode active material layer containing the lithium transition metal compound powder and a binder on a current collector (Claim 27).

  The lithium secondary battery of the present invention is a lithium secondary battery comprising a negative electrode capable of inserting and extracting lithium, a non-aqueous electrolyte containing a lithium salt, and a positive electrode capable of inserting and extracting lithium. Such a positive electrode for a lithium secondary battery of the present invention is used (claim 28).

  When the lithium transition metal-based compound powder for a lithium secondary battery positive electrode material of the present invention is used as a lithium secondary battery positive electrode material, it is possible to achieve both low cost and high safety with improved load characteristics. it can. For this reason, according to the present invention, a lithium secondary battery that is inexpensive, highly safe, and excellent in performance even when used at a high charging voltage is provided.

In Example 1, it is a graph which shows the pore distribution curve of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 2, it is a graph which shows the pore distribution curve of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 3, it is a graph which shows the pore distribution curve of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 4, it is a graph which shows the pore distribution curve of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 5, it is a graph which shows the pore distribution curve of the powder of the manufactured lithium nickel manganese cobalt complex oxide. In Example 6, it is a graph which shows the pore distribution curve of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 7, it is a graph which shows the pore distribution curve of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 8, it is a graph which shows the pore distribution curve of the lithium nickel manganese cobalt complex oxide powder manufactured. In Comparative example 1, it is a graph which shows the pore distribution curve of the lithium nickel manganese cobalt complex oxide powder manufactured. In Comparative example 2, it is a graph which shows the pore distribution curve of the lithium nickel manganese cobalt complex oxide powder manufactured. In Comparative example 3, it is a graph which shows the pore distribution curve of the lithium nickel manganese cobalt complex oxide powder manufactured. In Comparative example 4, it is a graph which shows the pore distribution curve of the lithium nickel manganese cobalt complex oxide powder manufactured. In Comparative Example 5, it is a graph showing a pore distribution curve of the manufactured lithium nickel manganese cobalt composite oxide powder. In Example 1, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide powder. In Example 2, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide powder. In Example 3, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide powder. In Example 4, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide powder. In Example 5, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide powder. In Example 6, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide powder. In Example 7, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide powder. In Example 8, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide powder. In Comparative example 1, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt complex oxide powder. In Comparative example 2, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide powder. In Comparative example 3, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide powder. In Comparative example 4, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide powder. In Comparative example 5, it is a SEM image (photograph) (magnification x10,000) of the manufactured lithium nickel manganese cobalt composite oxide powder. In Example 1, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 2, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 3, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 4, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 5, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 6, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 7, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 8, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide powder manufactured. In Comparative example 1, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide powder manufactured. In the comparative example 2, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide powder manufactured. In the comparative example 3, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide powder manufactured. In the comparative example 4, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide powder manufactured. In Comparative example 5, it is a graph which shows the XRD pattern of the lithium nickel manganese cobalt complex oxide powder manufactured. In Example 1, it is a graph which shows W density | concentration distribution from the particle | grain surface of the lithium nickel manganese cobalt complex oxide powder manufactured to the depth direction. In Example 3, it is a graph which shows Mo concentration distribution from the particle | grain surface of the lithium nickel manganese cobalt complex oxide powder manufactured to the depth direction. In Example 4, it is a graph which shows W concentration distribution from the particle | grain surface of the lithium nickel manganese cobalt complex oxide powder manufactured to the depth direction. In Example 5, it is a graph which shows Nb density | concentration distribution from the particle | grain surface of the lithium nickel manganese cobalt complex oxide powder manufactured to the depth direction. In Example 6, it is a graph which shows W concentration distribution from the particle | grain surface of the lithium nickel manganese cobalt complex oxide powder manufactured to the depth direction. In Example 7, it is a graph which shows W concentration distribution from the particle | grain surface of the lithium nickel manganese cobalt complex oxide powder manufactured to the depth direction. In Example 8, it is a graph which shows W density | concentration distribution from the particle | grain surface of the lithium nickel manganese cobalt complex oxide powder manufactured to the depth direction. In Comparative Example 2, it is a graph showing the W concentration distribution in the depth direction from the particle surface of the manufactured lithium nickel manganese cobalt composite oxide powder. In the comparative example 3, it is a graph which shows B density | concentration distribution from the particle | grain surface of the lithium nickel manganese cobalt complex oxide powder manufactured to the depth direction. In Comparative example 4, it is a graph which shows Sn density | concentration distribution from the particle | grain surface of the manufactured lithium nickel manganese cobalt complex oxide powder to the depth direction.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to the gist of the present invention. The content of is not specified.

[Lithium transition metal compound powder]
The lithium transition metal-based compound powder for a lithium secondary battery positive electrode material of the present invention (hereinafter sometimes referred to as “positive electrode active material”) is a transition metal compound having a function capable of inserting and removing lithium ions. 0.01 mol% or more based on the total molar amount of the transition metal elements in the main component raw material, the main component raw material containing at least one additive for suppressing grain growth and sintering during firing. After adding at a ratio of less than 2 mol%, it is fired.

<Lithium transition metal compound>
In the present invention, the “lithium transition metal compound” is a compound having a structure capable of desorbing and inserting Li ions, such as sulfides, phosphate compounds, lithium transition metal composite oxides, etc. Is mentioned. Examples of sulfides include compounds having a two-dimensional layered structure such as TiS ₂ and MoS ₂ , and strong compounds represented by the general formula Me _x Mo ₆ S ₈ (Me is various transition metals including Pb, Ag, and Cu). Examples thereof include a sugar compound having a three-dimensional skeleton structure. Examples of the phosphate compound include those belonging to the olivine structure, and are generally represented by LiMePO ₄ (Me is at least one or more transition metals), specifically, LiFePO ₄ , LiCoPO ₄ , LiNiPO ₄ , Examples include LiMnPO ₄ . Examples of the lithium transition metal composite oxide include spinel structures capable of three-dimensional diffusion and those belonging to a layered structure capable of two-dimensional diffusion of lithium ions. Those having a spinel structure are generally expressed as LiMe ₂ O ₄ (Me is at least one transition metal), specifically, LiMn ₂ O ₄ , LiCoMnO ₄ , LiNi _0.5 Mn _1.5 O. ₄ and CoLiVO ₄ . Those having a layered structure are generally expressed as LiMeO ₂ (Me is at least one or more transition metals), specifically, LiCoO ₂ , LiNiO ₂ , LiNi _1-x Co _x O ₂ , LiNi _{1-x. -y Co x Mn y O 2,} LiNi 0.5 Mn 0.5 O 2, Li 1.2 Cr 0.4 Mn 0.4 O 2, Li 1.2 Cr 0.4 Ti 0.4 O 2, Examples include LiMnO ₂ .

  The lithium transition metal-based compound powder of the present invention preferably includes a crystal structure belonging to an olivine structure, a spinel structure, or a layered structure from the viewpoint of lithium ion diffusion. Among these, those including a crystal structure belonging to a layered structure are particularly preferable.

  Further, foreign elements may be introduced into the lithium transition metal-based compound powder of the present invention. Different elements include B, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Fe, Mn, Co, Ni, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, and Mo. , Ru, Rh, Pd, Ag, In, Sn, Sb, Te, Ba, Ta, W, Re, Os, Ir, Pt, Au, Pb, Bi, La, Ce, Pr, Nd, Sm, Eu, Gd , Tb, Dy, Ho, Er, Tm, Yb, Lu, N, F, P, S, Cl, Br, and I are selected from one or more. These foreign elements may be incorporated into the crystal structure of the lithium transition metal compound, or may not be incorporated into the crystal structure of the lithium transition metal compound, and may be a single element or compound on the particle surface or crystal grain boundary. May be unevenly distributed.

<Additives that suppress grain growth and sintering during firing>
In the present invention, the term “additive that suppresses grain growth and sintering during firing” refers to an active material that suppresses sintering between primary particles or secondary particles during positive electrode active material firing at a high temperature. This refers to those that have the effect of suppressing the growth of particles and achieving high crystallization, and obtaining a fine powder property having a large number of voids.

  For example, when producing a lithium nickel manganese cobalt based composite oxide powder having a composition region defined by the composition formula (I) described later, which is suitable for the present invention, an aggregate of solid powder raw materials is fired at a temperature of 970 ° C. or higher. Thus, a positive electrode active material having a highly developed crystallinity and a preferable crystal structure for battery performance can be obtained. However, on the other hand, grain growth and sintering are also remarkably facilitated, resulting in powder properties that are undesirable for battery performance. In other words, it is extremely difficult to improve both of them at the same time, but by adding “additives that suppress grain growth and sintering during firing” and firing, this trade-off relationship can be overcome. It becomes possible to do.

  In the present invention, the specific compound added as an additive that suppresses grain growth and sintering during firing is not clear as to the mechanism that exerts the effect of suppressing grain growth and sintering during firing. Since compounds composed of metal elements that can be pentavalent or hexavalent have common effects, they are different from any of the cationic elements that constitute the lithium transition metal-based compound. It is possible to stably take an expensive number state such as a valence, and as a result of being hardly dissolved by a solid-phase reaction, it is unevenly distributed on the surface or grain boundary of the lithium transition metal compound particles. Therefore, it is presumed that the mass transfer due to the contact between the positive electrode active material particles is inhibited, and the growth and sintering of the particles are suppressed.

  The type of additive is not particularly limited as long as it exhibits the above effects, but contains an element selected from elements such as Mo, W, Nb, Ta, and Re, which are stable in an expensive state. A compound is preferable, and two or more of these elements may be appropriately used in combination. Usually, an oxide material is used as the additive containing these elements.

Exemplary compounds as an _{additive, MoO, MoO 2, MoO 3} , MoO x, Mo 2 O 3, Mo 2 O 5, Li 2 MoO 4, WO, WO 2, WO 3, WO x, W 2 O 3 , W ₂ O ₅ , W ₁₈ O ₄₉ , W ₂₀ O ₅₈ , W ₂₄ O ₇₀ , W ₂₅ O ₇₃ , W ₄₀ O ₁₁₈ , Li ₂ WO ₄ , NbO, NbO ₂ , Nb ₂ O, Nb ₂ O ₅ , Nb ₄ O, Nb ₆ O, LiNbO ₃ , TaO, TaO ₂ , Ta ₂ O ₅ , LiTaO ₃ , ReO ₂ , ReO ₃ , Re ₂ O _{3 and the} like can be mentioned, preferably MoO ₃ , Li ₂ MoO ₄ , WO ₃ , Li ₂ WO ₄ , LiNbO ₃ , Ta ₂ O ₅ , LiTaO ₃ , ReO ₃ , and particularly preferably WO ₃ , Li ₂ WO ₄ , and ReO ₃ .

  The range of the amount of these additives is usually 0.01 mol% or more, preferably 0.03 mol% or more, more preferably 0, based on the total molar amount of transition metal elements constituting the main component raw material. 0.04 mol% or more, particularly preferably 0.05 mol% or more, usually less than 2 mol%, preferably 1.8 mol% or less, more preferably 1.5 mol% or less, particularly preferably 1.3 mol% or less. It is. If the lower limit is not reached, the above effect may not be obtained. If the upper limit is exceeded, battery performance may be lowered.

  The lithium transition metal-based compound powder of the present invention has an additive-derived element (additive element), that is, preferably at least one selected from Mo, W, Nb, Ta and Re on the surface part of the primary particles. These elements are characterized by being concentrated. Specifically, the molar ratio of the total amount of additive elements to the total of metal elements other than Li and additive elements on the surface portion of the primary particles (that is, metal elements other than Li and the additive elements) is usually that of the entire particle. More than 5 times the atomic ratio. The lower limit of this ratio is preferably 7 times or more, more preferably 8 times or more, and particularly preferably 9 times or more. The upper limit is not particularly limited, but is preferably 150 times or less, more preferably 100 times or less, particularly preferably 50 times or less, and most preferably 30 times or less. If this ratio is too small, the effect of improving battery performance is small, while if too large, battery performance may be deteriorated.

  Analysis of the composition of the surface part of the primary particles of the lithium transition metal compound powder was performed by X-ray photoelectron spectroscopy (XPS), using monochromatic light AlKα as an X-ray source, an analysis area of 0.8 mm diameter, and an extraction angle of 65 °. Perform under the conditions of Although the range (depth) that can be analyzed varies depending on the composition of the primary particles, it is usually 0.1 nm to 50 nm, particularly 1 nm to 10 nm for a positive electrode active material. Therefore, in the present invention, the surface portion of the primary particles of the lithium transition metal-based compound powder indicates a measurable range under these conditions.

<Presence of additive elements>
The lithium transition metal-based compound powder of the present invention preferably has a continuous composition gradient structure in which the additive element exists with a concentration gradient in the depth direction from the particle surface.

The composition of the lithium transition metal compound powder in the depth direction from the particle surface can be analyzed by alternately performing Ar ion gun sputtering and the same XPS measurement as described above. Since atoms near the surface are removed by sputtering, the subsequent XPS measurement reflects the composition inside the particles before sputtering. Here, since it is difficult to accurately know the thickness of the surface layer removed by sputtering, the thickness of the SiO ₂ surface layer removed by performing sputtering of the SiO ₂ thin film under the same conditions is substituted. Therefore, in this invention, the depth from the particle | grain surface of a lithium transition metal type compound shows the depth estimated by this method.

The atomic ratio R ₀ of the total of the additive element to the total of Li and the metal element other than the additive element (that is, the metal element other than Li and the additive element) on the outermost surface of the particles of the lithium transition metal compound powder of the present invention And a ratio R ₀ / of the total atomic ratio R ₁₀ of the additive element to the total of Li and a metal element other than the additive element at a depth of 10 nm from the particle surface (that is, Li and the additive element). R ₁₀ is usually 3 times or more, preferably 3.2 times or more, usually 50 times or less, preferably 30 fold or less, more preferably 10 times or less, more preferably 8 times or less, and most preferably 6 times or less It is.

<Median diameter and 90% integrated diameter ( _D90 )>
The median diameter of the lithium transition metal compound powder of the present invention is usually 0.1 μm or more, preferably 0.3 μm or more, more preferably 0.6 μm or more, further preferably 0.8 μm or more, and most preferably 1.2 μm or more. In general, it is 5 μm or less, preferably 4 μm or less, more preferably 3 μm or less, still more preferably 2.8 μm or less, and most preferably 2.5 μm or less. When the median diameter is less than this lower limit, there is a possibility that a problem occurs in the coating property at the time of forming the positive electrode active material layer, and when the upper limit is exceeded, battery performance may be deteriorated.

The 90% cumulative diameter (D ₉₀ ) of the secondary particles of the lithium transition metal-based compound powder of the present invention is usually 10 μm or less, preferably 8 μm or less, more preferably 6 μm or less, and most preferably 5 μm or less, usually 0. 0.5 μm or more, preferably 0.8 μm or more, more preferably 1 μm or more, and most preferably 1.5 μm or more. If the 90% cumulative diameter (D ₉₀ ) exceeds the above upper limit, the battery performance may be deteriorated, and if it is less than the lower limit, there is a possibility of causing a problem in the coating property when forming the positive electrode active material layer.

In the present invention, the median diameter and the 90% cumulative diameter (D ₉₀ ) as the average particle diameter are set to a refractive index of 1.24 using a known laser diffraction / scattering particle size distribution measuring device, and the particle diameter standard is determined. Measured as a volume reference. In the present invention, a 0.1 wt% sodium hexametaphosphate aqueous solution was used as a dispersion medium used in the measurement, and the measurement was performed after ultrasonic dispersion (output 30 W, frequency 22.5 kHz) for 5 minutes.

<Average primary particle size>
The average primary particle diameter (average primary particle diameter) of the lithium transition metal compound powder of the present invention is not particularly limited, but the lower limit is preferably 0.1 μm or more, more preferably 0.15 μm or more, and further Preferably it is 0.2 μm or more, most preferably 0.25 μm or more, and the upper limit is preferably 0.9 μm or less, more preferably 0.8 μm or less, further preferably 0.7 μm or less, most preferably 0.5 μm. It is as follows. If the average primary particle size exceeds the above upper limit, the battery performance such as rate characteristics and output characteristics may be lowered because the powder filling properties are adversely affected and the specific surface area is reduced. There is sex. If the lower limit is not reached, there is a possibility that problems such as inferior reversibility of charge / discharge due to the undeveloped crystals.

  In addition, the average primary particle diameter in this invention is an average diameter observed with the scanning electron microscope (SEM), and the average particle diameter of about 10-30 primary particles using a SEM image of 30,000 times. It can be obtained as a value.

<BET specific surface area>
The lithium-lithium transition metal compound powder of the present invention also has a BET specific surface area of usually 1.5 m ² / g or more, preferably 1.6 m ² / g or more, more preferably 1.7 m ² / g or more, most preferably It is preferably 1.8 m ² / g or more, usually 5 m ² / g or less, preferably 4 m ² / g or less, more preferably 3.5 m ² / g or less, and most preferably 3 m ² / g or less. If the BET specific surface area is smaller than this range, the battery performance is likely to be lowered.

  The BET specific surface area can be measured by a known BET type powder specific surface area measuring device. In the present invention, an OMS Riken: AMS8000 type automatic powder specific surface area measuring device was used, nitrogen was used as an adsorption gas, and helium was used as a carrier gas. Specifically, the powder sample was heated and deaerated with a mixed gas at a temperature of 150 ° C., then cooled to liquid nitrogen temperature to adsorb the mixed gas, and then heated to room temperature with water to be adsorbed. Nitrogen gas was desorbed, the amount was detected by a heat conduction detector, and the specific surface area of the sample was calculated therefrom.

<Pore characteristics by mercury intrusion method>
The lithium transition metal-based compound powder for a lithium secondary battery positive electrode material of the present invention preferably satisfies a specific condition in measurement by a mercury intrusion method.

The mercury intrusion method employed in the evaluation of the lithium transition metal compound powder of the present invention will be described below.
The mercury intrusion method is a method for obtaining information such as specific surface area and pore diameter distribution from the relationship between pressure and the amount of mercury intruded into a pore of a sample such as porous particles while applying pressure. It is.

  Specifically, first, the container containing the sample is evacuated and filled with mercury. Mercury has a high surface tension, and as it is, mercury does not penetrate into the pores on the sample surface, but when pressure is applied to the mercury and the pressure is gradually increased, the pores increase in size from the smallest to the smallest. Gradually mercury enters the pores. If a change in the mercury liquid level (that is, the amount of mercury intruded into the pores) is detected while the pressure is continuously increased, a mercury intrusion curve representing the relationship between the pressure applied to the mercury and the amount of mercury intruded can be obtained. .

Here, assuming that the pore shape is cylindrical, the radius is r, the surface tension of mercury is δ, and the contact angle is θ, the size in the direction of pushing mercury out of the pore is −2πrδ (cos θ). (If θ> 90 °, this value is positive). Moreover, since the magnitude of the force in the direction of pushing mercury into the pores under the pressure P is represented by πr ² P, the following formulas (1) and (2) are derived from the balance of these forces. It will be.

-2πrδ (cosθ) = πr ² P (1)
Pr = −2δ (cos θ) (2)

  In the case of mercury, values of surface tension δ = 480 dyn / cm and contact angle θ = 140 ° are generally used. When these values are used, the radius of the pore into which mercury is injected under the pressure P is expressed by the following formula (3).

  That is, since there is a correlation between the pressure P applied to mercury and the radius r of the pore into which mercury enters, the size of the pore radius of the sample and its volume are calculated based on the obtained mercury intrusion curve. A pore distribution curve representing the relationship can be obtained. For example, when the pressure P is changed from 0.1 MPa to 100 MPa, the pores in the range from about 7500 nm to about 7.5 nm can be measured.

Note that the approximate measurement limit of the pore radius by the mercury intrusion method is that the lower limit is about 2 nm or more and the upper limit is about 200 μm or less, and the pores in a relatively large range compared to the nitrogen adsorption method described later. It can be said that it is suitable for analysis of distribution.
Measurement by the mercury intrusion method can be performed using an apparatus such as a mercury porosimeter. Specific examples of the mercury porosimeter include an autopore manufactured by Micromeritics, a pore master manufactured by Quantachrome, and the like.

Lithium transition metal based compound powder according to the present invention, in a mercury intrusion curve obtained by mercury intrusion porosimetry, mercury penetration amount at boosting the pressure 3.86kPa to 413MPa is 0.7 cm ³ / g or more, 1.5 cm ³ / g or less is preferable. Mercury intrusion volume is more preferably 0.74 cm ³ / g or more, more preferably 0.8 cm ³ / g or more, and most preferably 0.9 cm ³ / g or more, more preferably 1.4 cm ³ / g or less, More preferably, it is 1.3 cm < ³ > / g or less, Most preferably, it is 1.2 cm < ³ > / g or less. When the upper limit of this range is exceeded, the voids become excessive, and when the lithium transition metal-based compound powder of the present invention is used as the positive electrode material, the filling rate of the positive electrode active material into the positive electrode plate (positive electrode current collector) is lowered. As a result, the battery capacity is limited. On the other hand, if the lower limit of this range is not reached, voids between particles become too small. Therefore, when a battery is produced using the lithium transition metal compound powder of the present invention as a positive electrode material, lithium diffusion between particles is inhibited. As a result, the load characteristics deteriorate.

In the lithium transition metal-based compound powder of the present invention, the specific main peak described below usually appears when the pore distribution curve is measured by the mercury intrusion method described above.
In the present specification, the “pore distribution curve” refers to the total pore volume per unit weight (usually 1 g) of pores having a radius larger than the radius on the horizontal axis. A value obtained by differentiating the logarithm of the pore radius is plotted on the vertical axis, and is usually expressed as a graph connecting the plotted points. In particular, the pore distribution curve obtained by measuring the lithium transition metal-based compound powder of the present invention by mercury porosimetry is referred to as “the pore distribution curve according to the present invention” as appropriate in the following description.

In this specification, “main peak” refers to the largest peak among the peaks of the pore distribution curve, and “sub peak” refers to peaks other than the main peak of the pore distribution curve.
Further, in this specification, “peak top” refers to a point where the coordinate value of the vertical axis takes the largest value in each peak of the pore distribution curve.

(Main peak)
The main peak of the pore distribution curve according to the present invention has a peak top whose pore radius is usually 300 nm or more, preferably 350 nm or more, most preferably 400 nm or more, and usually 1000 nm or less, preferably 980 nm or less. Preferably it exists in the range of 970 nm or less, more preferably 960 nm or less, and most preferably 950 nm or less. When the upper limit of this range is exceeded, when a battery is made using the lithium transition metal compound powder of the present invention as a positive electrode material, lithium diffusion in the positive electrode material is hindered or the conductive path is insufficient, resulting in load characteristics. May be reduced. On the other hand, below the lower limit of this range, when a positive electrode is produced using the lithium transition metal compound powder of the present invention, the necessary amount of conductive material and binder increases, and the positive electrode plate (positive electrode current collector) increases. There is a possibility that the filling rate of the positive electrode active material into the body) is restricted, and the battery capacity is restricted. In addition, with the formation of fine particles, the mechanical properties of the coating film at the time of coating become hard or brittle, and there is a possibility that the coating film is likely to be peeled off during the winding process during battery assembly.

Moreover, the pore volume of the peak having a peak top at a pore radius of 300 nm or more and 1000 nm or less, which the pore distribution curve according to the present invention has, is preferably usually 0.4 cm ³ / g or more, preferably 0. .41cm ³ / g or more, more preferably 0.42 cm ³ / g or more, most preferably 0.43 cm ³ / g or more, and usually ^{1 cm} 3 / g or less, preferably 0.8 cm ³ / g or less, more preferably it is 0.7 cm ³ / g or less, and most preferably not more than 0.6 cm ³ / g. When the upper limit of this range is exceeded, the voids become excessive, and when the lithium transition metal compound powder of the present invention is used as the positive electrode material, the filling rate of the positive electrode active material into the positive electrode plate becomes low, and the battery capacity is limited. There is a possibility of being. On the other hand, if the lower limit of this range is not reached, voids between the particles become excessively small. Therefore, when a battery is produced using the lithium transition metal compound powder of the present invention as a positive electrode material, lithium diffusion between secondary particles is performed. May be hindered and load characteristics may deteriorate.

(Sub peak)
The pore distribution curve according to the present invention may have a plurality of sub-peaks in addition to the main peak described above, but preferably does not exist within the pore radius range of 80 nm or more and 300 nm or less.

<The bulk density>
The bulk density of the lithium transition metal compound powder of the present invention is usually 0.5 g / cc or more, preferably 0.6 g / cc or more, more preferably 0.7 g / cc or more, most preferably 0.8 g / cc or more. In general, it is 1.7 g / cc or less, preferably 1.6 g / cc or less, more preferably 1.5 g / cc or less, and most preferably 1.3 g / cc or less. It is preferable for the bulk density to exceed this upper limit for improving powder filling properties and electrode density, but the specific surface area may be too low, and battery performance may be reduced. When the bulk density is lower than this lower limit, there is a possibility of adversely affecting the powder filling property and electrode preparation.
In the present invention, the bulk density is 5 to 10 g of lithium transition metal compound powder in a 10 ml glass graduated cylinder and tapped 200 times with a stroke of about 20 mm (tap density) g / Calculate as cc.

<Volume resistivity>
The volume resistivity value when the lithium transition metal compound powder of the present invention is compacted at a pressure of 40 MPa is preferably 1 × 10 ³ Ω · cm or more as a lower limit, and more preferably 5 × 10 ³ Ω · cm or more. More preferred is 1 × 10 ⁴ Ω · cm or more. The upper limit is preferably 1 × 10 ⁶ Ω · cm or less, more preferably 5 × 10 ⁵ Ω · cm or less, and further preferably 1 × 10 ⁶ Ω · cm or less. If this volume resistivity exceeds this upper limit, the load characteristics when used as a battery may be reduced. On the other hand, if the volume resistivity is below this lower limit, the safety of the battery may be reduced.

  In the present invention, the volume resistivity of the lithium transition metal based compound powder is such that the four probe / ring electrode, the electrode spacing is 5.0 mm, the electrode radius is 1.0 mm, the sample radius is 12.5 mm, and the applied voltage limiter is 90 V. The volume resistivity measured in a state where the lithium transition metal-based compound powder is compacted at a pressure of 40 MPa. The volume resistivity can be measured, for example, by using a powder resistance measuring device (for example, Lorester GP powder resistance measuring system manufactured by Dia Instruments Co., Ltd.) with a powder probe unit on a powder under a predetermined pressure. It can be carried out.

（以下「層状Ｒ（−３）ｍ構造」と表記することがある。）に帰属される。 <Crystal structure>
The lithium transition metal-based compound powder of the present invention is preferably composed mainly of a lithium nickel manganese cobalt-based composite oxide including a crystal structure belonging to a layered structure.
Here, the layered structure will be described in more detail. As a typical crystal system having a layered structure, there are those belonging to the α-NaFeO ₂ type such as LiCoO ₂ and LiNiO ₂ , which are hexagonal systems, and because of their symmetry, the space group

(Hereinafter referred to as “layered R (−3) m structure”).

However, the layered LiMeO ₂ is not limited to the layered R (−3) m structure. In addition, LiMnO ₂ called so-called layered Mn is an orthorhombic layered compound having a space group Pm2m, and Li ₂ MnO ₃ called so-called 213 phase is Li [Li _1/3 Mn _2/3 ]. O ₂ , which is a monoclinic space group C2 / m structure, is also a layered compound in which a Li layer, a [Li _1/3 Mn _2/3 ] layer, and an oxygen layer are stacked.

<composition>
The lithium transition metal compound powder of the present invention is preferably a lithium transition metal compound powder represented by the following composition formula (I).
LiMO ₂ (I)
However, M is an element composed of Li, Ni and Mn, or Li, Ni, Mn and Co, and the Mn / Ni molar ratio is usually 0.3 or more, preferably 0.5 or more, more preferably Is 0.6 or more, more preferably 0.7 or more, still more preferably 0.8 or more, most preferably 0.9 or more, usually 5 or less, preferably 4 or less, more preferably 3 or less, still more preferably 2 .5 or less, most preferably 1.5 or less. The Co / (Mn + Ni + Co) molar ratio is usually 0 or more, preferably 0.01 or more, more preferably 0.02 or more, still more preferably 0.03 or more, most preferably 0.05 or more, usually 0.30 or less, preferably Is 0.20 or less, more preferably 0.15 or less, still more preferably 0.10 or less, and most preferably 0.099 or less. Li molar ratio in M is 0.001 or more, preferably 0.01 or more, more preferably 0.02 or more, further preferably 0.03 or more, most preferably 0.05 or more, usually 0.2 or less, preferably Is 0.19 or less, more preferably 0.18 or less, still more preferably 0.17 or less, and most preferably 0.15 or less.

  In the above composition formula (I), the atomic ratio of the oxygen amount is described as 2 for convenience, but there may be some non-stoichiometry. In the case of non-stoichiometry, the atomic ratio of oxygen is usually in the range of 2 ± 0.2, preferably in the range of 2 ± 0.15, more preferably in the range of 2 ± 0.12, and even more preferably 2 ± 0.10. And particularly preferably in the range of 2 ± 0.05.

  In addition, the lithium transition metal-based compound powder of the present invention is preferably obtained by firing at a high temperature in an oxygen-containing gas atmosphere in order to increase the crystallinity of the positive electrode active material. In particular, in the lithium nickel manganese cobalt based composite oxide having the composition represented by the above composition formula (I), the lower limit of the firing temperature is usually 900 ° C. or higher, preferably 925 ° C. or higher, more preferably 950 ° C. or higher, still more preferably. Is 975 ° C. or higher, most preferably 990 ° C. or higher, and the upper limit is usually 1200 ° C. or lower, preferably 1175 ° C. or lower, more preferably 1150 ° C. or lower, and most preferably 1125 ° C. or lower. If the firing temperature is too low, heterogeneous phases are mixed, and the lattice distortion increases without developing a crystal structure. Moreover, the specific surface area becomes too large. Conversely, if the firing temperature is too high, the primary particles grow excessively, sintering between the particles proceeds too much, and the specific surface area becomes too small.

<Contained carbon concentration C>
The carbon concentration C (% by weight) value of the lithium transition metal compound powder of the present invention is usually 0.005% by weight or more, preferably 0.01% by weight or more, more preferably 0.015% by weight or more. Preferably it is 0.02% by weight or more, usually 0.25% by weight or less, preferably 0.2% by weight or less, more preferably 0.15% by weight or less, more preferably 0.1% by weight or less, most preferably Is 0.07% by weight or less. If the lower limit is not reached, battery performance may be reduced. If the upper limit is exceeded, swelling due to gas generation when the battery is produced may increase or battery performance may be reduced.

In the present invention, the carbon concentration C contained in the lithium transition metal compound powder is determined by measurement by combustion in an oxygen stream (high-frequency heating furnace type) infrared absorption method, as shown in the Examples section below.
In addition, the carbon component contained in the lithium transition metal-based compound powder obtained by carbon analysis described later can be regarded as indicating information about the amount of carbonic acid compound, particularly lithium carbonate. This is due to the fact that the carbon amount determined by carbon analysis is assumed to be all derived from carbonate ions, and the carbonate ion concentration analyzed by ion chromatography generally agrees.

  On the other hand, when a composite treatment with conductive carbon is performed as a method for increasing the electron conductivity, a C amount exceeding the specified range may be detected, but such a treatment was performed. The C value in the case is not limited to the specified range.

<Preferred composition>
The lithium transition metal compound powder for a lithium secondary battery positive electrode material of the present invention is particularly preferably one in which the atomic configuration in the M site in the composition formula (I) is represented by the following formula (II).
M = Li _{z / (2 + z)} {(Ni _{(1 + y) / 2} Mn _{(1-y) / 2} ) _1-x Co _x } _{2 / (2 + z)} (II)
(However, in the above formula (II),
0 ≦ x ≦ 0.1
−0.1 ≦ y ≦ 0.1,
(1-x) (0.05-0.98y) ≤z≤ (1-x) (0.20-0.88y)
It is. )

  In the above formula (II), the value of x is usually 0 or more, preferably 0.01 or more, more preferably 0.02 or more, still more preferably 0.03 or more, most preferably 0.04 or more, usually 0.1. In the following, it is preferably 0.099 or less, more preferably 0.098 or less, further preferably 0.08 or less, more preferably 0.06 or less, and most preferably 0.05 or less.

  The value of y is usually −0.1 or more, preferably −0.05 or more, more preferably −0.03 or more, most preferably −0.02 or more, usually 0.1 or less, preferably 0.05 or less, More preferably, it is 0.03 or less, and most preferably 0.02 or less.

  The value of z is usually (1-x) (0.05-0.98y) or more, preferably (1-x) (0.06-0.98y) or more, more preferably (1-x) (0. 07-0.98y) or more, more preferably (1-x) (0.08-0.98y) or more, most preferably (1-x) (0.10-0.98y) or more, usually (1- x) (0.20-0.88y) or less, preferably (1-x) (0.18-0.88y) or less, more preferably (1-x) (0.17-0.88y), most Preferably, it is (1-x) (0.16-0.88y) or less. If z is below this lower limit, the conductivity will decrease, and if it exceeds the upper limit, the amount of substitution to transition metal sites will increase so much that the battery capacity will decrease, leading to a decrease in the performance of lithium secondary batteries using this. There is sex. On the other hand, if z is too large, the carbon dioxide absorbability of the active material powder increases, so that it becomes easy to absorb carbon dioxide in the atmosphere. As a result, it is estimated that the concentration of contained carbon increases.

  In the composition range of the above formula (II), the closer the z value is to the lower limit that is a constant ratio, the lower the rate characteristics and output characteristics as a battery, and the lower the z value is to the upper limit, Although the rate characteristics and output characteristics of the battery are improved, there is a tendency for the capacity to decrease. In addition, the lower the y value, that is, the smaller the manganese / nickel atomic ratio, the higher the capacity is obtained at a lower charging voltage. However, the cycle characteristics and safety of batteries set at a higher charging voltage tend to be reduced. As the value is closer to the upper limit, the cycle characteristics and safety of the battery set at a higher charge voltage are improved, while the discharge capacity, rate characteristics, and output characteristics tend to decrease. In addition, the closer the x value is to the lower limit, the lower the load characteristics such as rate characteristics and output characteristics when the battery is used. Conversely, the closer the x value is to the upper limit, the rate characteristics when the battery is used. However, if this upper limit is exceeded, the cycle characteristics and safety when set at a high charge voltage are reduced, and the raw material cost is increased. Setting the composition parameters x, y, and z within a specified range is an important component of the present invention.

Here, the chemical meaning of the Li composition (z and x) in the lithium nickel manganese cobalt composite oxide, which is a preferred composition of the lithium transition metal compound powder of the present invention, will be described in more detail below.
As described above, the layered structure is not necessarily limited to the R (-3) m structure, but is preferably one that can be attributed to the R (-3) m structure from the viewpoint of electrochemical performance.
In order to obtain x, y, and z in the composition formula of the lithium nickel manganese cobalt based composite oxide, each transition metal and Li are analyzed with an inductively coupled plasma emission spectrometer (ICP-AES), and Li / Ni / Calculated by determining the ratio of Mn / Co.

  From a structural point of view, it is considered that Li related to z is substituted for the same transition metal site. Here, due to Li related to z, the average valence of Ni becomes larger than divalent (trivalent Ni is generated) by the principle of charge neutrality. Since z raises the Ni average valence, it becomes an index of the Ni valence (the ratio of Ni (III)).

となる。この計算結果は、Ｎｉ価数はｚのみで決まるのではなく、ｘ及びｙの関数となっていることを意味している。ｚ＝０かつｙ＝０であれば、ｘの値に関係なくＮｉ価数は２価のままである。ｚが負の値になる場合は、活物質中に含まれるＬｉ量が化学量論量より不足していることを意味し、あまり大きな負の値を有するものは本発明の効果が出ない可能性がある。一方、同じｚ値であっても、Ｎｉリッチ（ｙ値が大きい）及び／又はＣｏリッチ（ｘ値が大きい）な組成ほどＮｉ価数は高くなるということを意味し、電池に用いた場合、レート特性や出力特性が高くなるが、反面、容量低下しやすくなる結果となる。このことから、ｚ値の上限と下限はｘ及びｙの関数として規定するのがより好ましいと言える。 From the above composition formula, when calculating the Ni valence (m) accompanying the change of z, the Co valence is trivalent and the Mn valence is tetravalent,

It becomes. This calculation result means that the Ni valence is not determined only by z but is a function of x and y. If z = 0 and y = 0, the Ni valence remains divalent regardless of the value of x. When z is a negative value, it means that the amount of Li contained in the active material is less than the stoichiometric amount, and those having a very large negative value may not have the effect of the present invention. There is sex. On the other hand, even if the z value is the same, it means that the Ni valence becomes higher as the composition is rich in Ni (large y value) and / or rich in Co (large x value). The rate characteristics and output characteristics are improved, but on the other hand, the capacity tends to decrease. From this, it can be said that it is more preferable to define the upper and lower limits of the z value as a function of x and y.

  In addition, when the x value is in the range of 0 ≦ x ≦ 0.1 and the amount of Co is small, in addition to reducing the cost, it was used as a lithium secondary battery designed to be charged at a high charging potential. In some cases, charge / discharge capacity, cycle characteristics, and safety are improved.

<Powder X-ray diffraction peak>
In the present invention, the lithium nickel manganese cobalt based composite oxide powder having a composition satisfying the composition formulas (I) and (II) has a diffraction angle 2θ of 64.5 in a powder X-ray diffraction pattern using CuKα rays. When the half-value width of the (110) diffraction peak existing in the vicinity of ° is FWHM (110), the range is 0.01 ≦ FWHM (110) ≦ 0.2.
In general, since the half width of the X-ray diffraction peak is used as a measure of crystallinity, the present inventors have intensively investigated the correlation between crystallinity and battery performance. As a result, it has been found that when the half-value width of the (110) diffraction peak having a diffraction angle 2θ of around 64.5 ° is within the specified range, good battery performance is exhibited.

  In the present invention, FWHM (110) is usually 0.01 or more, preferably 0.05 or more, more preferably 0.10 or more, still more preferably 0.12 or more, and most preferably 0.14 or more, 0.2 or less. More preferably, it is 0.198 or less, More preferably, it is 0.196 or less, Most preferably, it is 0.194 or less.

In the present invention, the lithium nickel manganese cobalt composite oxide powder having a composition satisfying the composition formulas (I) and (II) has a diffraction angle 2θ of 64 in powder X-ray diffraction measurement using CuKα rays. In the (018) diffraction peak existing at around 0 °, the (110) diffraction peak around 64.5 °, and the (113) diffraction peak around 68 °, a different phase is present on the higher angle side than the peak top. In the case where the diffraction peak derived from the original phase does not exist or the diffraction peak derived from the different phase is present, the integrated intensity ratio of the different phase peak to the diffraction peak of the original crystal phase is preferably in the following range.
0 ≦ I ₀₁₈ ^* / I ₀₁₈ ≦ 0.30
0 ≦ I ₁₁₀ ^* / I ₁₁₀ ≦ 0.25
0 ≦ I ₁₁₃ ^* / I ₁₁₃ ≦ 0.30
(Here, I ₀₁₈ , I ₁₁₀ , and I ₁₁₃ represent the integrated intensities of (018), (110), and (113) diffraction peaks, respectively, and I ₀₁₈ ^* , I ₁₁₀ ^* , and I ₁₁₃ ^* are (018 ), (110), (113) represents the integrated intensity of a diffraction peak derived from a different phase appearing at a higher angle than the peak top of the diffraction peak.)

By the way, although the details of the causative substance of the diffraction peak derived from this heterogeneous phase are not clear, when a heterogeneous phase is included, the capacity, rate characteristics, cycle characteristics, etc. when used as a battery deteriorate. For this reason, the diffraction peak may have a diffraction peak that does not adversely affect the battery performance of the present invention, but is preferably a ratio in the above range, and the diffraction peak derived from a different phase with respect to each diffraction peak. The integrated intensity ratio is usually I ₀₁₈ ^* / I ₀₁₈ ≦ 0.30, I ₁₁₀ ^* / I ₁₁₀ ≦ 0.25, I ₁₁₃ ^* / I ₁₁₃ ≦ 0.30, preferably I ₀₁₈ ^* / I ₀₁₈ ≦ 0. 25, I ₁₁₀ ^* / I ₁₁₀ ≦ 0.20, I ₁₁₃ ^* / I ₁₁₃ ≦ 0.25, more preferably I ₀₁₈ ^* / I ₀₁₈ ≦ 0.20, I ₁₁₀ ^* / I ₁₁₀ ≦ 0.15, I ₁₁₃ ^* / _{I 113} ≦ 0.20, more preferably ^{_{I 018 * / I 018 ≦ 0.15}} , I 110 * / I 110 ≦ 0.10, an _{I 113 * / I 113 ≦ 0.15} , It is particularly preferred is also preferably no diffraction peaks derived from heterogeneous phases.

<Reason why the lithium transition metal-based compound powder of the present invention provides the above effects>
The reason why the lithium transition metal-based compound powder of the present invention brings about the above-described effect is considered as follows.
That is, the lithium transition metal-based compound powder of the present invention is used because the crystal particles are miniaturized, the amount of mercury intrusion at the time of pressurization in the mercury intrusion curve is large, and the pore volume between crystal particles is large. In addition to being able to increase the contact area between the surface of the positive electrode active material and the electrolyte when the battery is manufactured, the result is that the crystallinity is highly developed and the ratio of foreign phases is extremely low It is estimated that the load characteristics necessary as the positive electrode active material have been improved to a practical level.

[Method for producing lithium transition metal compound powder for positive electrode material of lithium secondary battery]
The method for producing the lithium transition metal compound powder of the present invention is not limited to a specific production method, but at least selected from lithium compounds and V, Cr, Mn, Fe, Co, Ni, and Cu. One or more transition metal compounds and an additive for suppressing grain growth and sintering during firing were pulverized in a liquid medium, and a slurry preparation step for obtaining a slurry in which these were uniformly dispersed was obtained. Preferably produced by the method for producing a lithium transition metal compound powder for a lithium secondary battery positive electrode material of the present invention, comprising a spray drying step of spray drying the slurry and a firing step of firing the obtained spray dried powder. Is done.

  For example, a lithium nickel manganese cobalt based composite oxide powder will be described as an example. A lithium compound, a nickel compound, a manganese compound, a cobalt compound, and an additive that suppresses grain growth and sintering during firing are contained in a liquid medium. The spray-dried body obtained by spray-drying the slurry dispersed in can be produced by firing in an oxygen-containing gas atmosphere.

  Hereinafter, the method for producing a lithium transition metal-based compound powder of the present invention will be described in detail by taking as an example the method for producing a lithium nickel manganese cobalt-based composite oxide powder which is a preferred embodiment of the present invention.

<Slurry preparation process>
Among the raw material compounds used in the preparation of the slurry in producing the lithium transition metal-based compound powder by the method of the present invention, the lithium compounds include Li ₂ CO ₃ , LiNO ₃ , LiNO ₂ , LiOH, LiOH · H _2. Examples include O, LiH, LiF, LiCl, LiBr, LiI, CH ₃ OOLi, Li ₂ O, Li ₂ SO ₄ , dicarboxylic acid Li, citric acid Li, fatty acid Li, and alkyl lithium. Among these lithium compounds, lithium compounds that do not contain nitrogen, sulfur, or halogen atoms are preferred because they do not generate harmful substances such as SO _x and NO _x during the firing process. It is a compound that tends to form voids by generating cracked gas in the secondary particles of the spray-dried powder due to the generation of cracked gas. Taking these points into consideration, Li ₂ CO ₃ , LiOH, among others LiOH.H ₂ O is particularly easy to handle and is relatively inexpensive, so Li ₂ CO ₃ is preferable. These lithium compounds may be used alone or in combination of two or more.

Moreover, as a nickel compound, Ni (OH) ₂ , NiO, NiOOH, NiCO ₃ , 2NiCO ₃ .3Ni (OH) ₂ .4H ₂ O, NiC ₂ O ₄ .2H ₂ O, Ni (NO ₃ ) ₂ .6H ₂ O, NiSO ₄ , NiSO ₄ .6H ₂ O, fatty acid nickel, nickel halide and the like. Among these, Ni (OH) ₂ , NiO, NiOOH, NiCO ₃ , 2NiCO ₃ .3Ni (OH) ₂ .4H ₂ O, NiC are used in that no harmful substances such as SO _X and NO _X are generated during the firing process. Nickel compounds such as ₂ O ₄ .2H ₂ O are preferred. Further, from the viewpoint that it can be obtained as an industrial raw material at a low cost, and from the viewpoint of high reactivity, Ni (OH) ₂ , NiO, NiOOH, NiCO ₃ , and further generation of decomposition gas during firing, spray dried powder Ni (OH) ₂ , NiOOH, and NiCO ₃ are particularly preferable from the viewpoint of easily forming voids in the secondary particles. These nickel compounds may be used alone or in combination of two or more.

In addition, manganese compounds such as Mn ₂ O ₃ , MnO ₂ , Mn ₃ O ₄ , manganese oxide, MnCO ₃ , Mn (NO ₃ ) ₂ , MnSO ₄ , manganese acetate, manganese dicarboxylate, manganese citrate, fatty acid manganese And manganese salts such as oxyhydroxide, manganese chloride and the like. Among these manganese compounds, MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ , and MnCO ₃ do not generate gases such as SO _X and NO _X during firing, and can be obtained at low cost as industrial raw materials. Therefore, it is preferable. These manganese compounds may be used individually by 1 type, and may use 2 or more types together.

Further, as the cobalt compound, Co (OH) ₂ , CoOOH, CoO, Co ₂ O ₃ , Co ₃ O ₄ , Co (OCOCH ₃ ) ₂ .4H ₂ O, CoCl ₂ , Co (NO ₃ ) ₂ .6H ₂ O, Co (SO ₄ ) ₂ · 7H ₂ O, CoCO _{3 and the} like. Among them, Co (OH) ₂ , CoOOH, CoO, Co ₂ O ₃ , Co ₃ O ₄ , and CoCO ₃ are preferable, and more preferably, from the viewpoint of not generating harmful substances such as SO _X and NO _X during the firing step. Co (OH) ₂ and CoOOH are industrially inexpensively available and highly reactive. In addition, Co (OH) ₂ , CoOOH, and CoCO ₃ are particularly preferable from the viewpoint of easily forming voids in the secondary particles of the spray-dried powder by generating decomposition gas during firing. These cobalt compounds may be used individually by 1 type, and may use 2 or more types together.

  In addition to the above Li, Ni, Mn, and Co raw material compounds, other elements are substituted to introduce the above-mentioned foreign elements, and voids in secondary particles formed by spray drying described later are efficiently formed. It is possible to use a group of compounds intended to be used. In addition, the addition stage of the compound used for the purpose of efficiently forming the voids of the secondary particles used here can be selected either before or after mixing the raw materials depending on the property. It is. In particular, it is preferable to add a compound that is easily decomposed due to mechanical shear stress applied by the mixing step after the mixing step.

  As described above, the additive for suppressing grain growth and sintering during firing is not particularly limited as long as it exhibits the desired effect, but Mo and W are stable in an expensive state. A compound containing an element selected from elements such as Nb, Ta, and Re is preferable, and an oxide material is usually used.

Exemplary compounds for additives that suppress grain growth and sintering during firing include MoO, MoO ₂ , MoO ₃ , MoO _x , Mo ₂ O ₃ , Mo ₂ O ₅ , Li ₂ MoO ₄ , WO, WO ₂ , WO ₃ , WO _x , W ₂ O ₃ , W ₂ O ₅ , W ₁₈ O ₄₉ , W ₂₀ O ₅₈ , W ₂₄ O ₇₀ , W ₂₅ O ₇₃ , W ₄₀ O ₁₁₈ , Li ₂ WO ₄ , NbO, NbO ₂ Nb ₂ O, Nb ₂ O ₅ , Nb ₄ O, Nb ₆ O, LiNbO ₃ , TaO, TaO ₂ , Ta ₂ O ₅ , LiTaO ₃ , ReO ₂ , ReO ₃ , Re ₂ O _{3 and the} like are preferable. Includes MoO ₃ , Li ₂ MoO ₄ , WO ₃ , Li ₂ WO ₄ , LiNbO ₃ , Ta ₂ O ₅ , LiTaO ₃ , ReO ₃ , and particularly preferably WO ₃ , Li ₂ WO ₄ , R eO ₃ may be mentioned. These additives may be used individually by 1 type, and may use 2 or more types together.

The method for mixing the raw materials is not particularly limited, and may be wet or dry. For example, a method using an apparatus such as a ball mill, a vibration mill, or a bead mill can be used. Wet mixing in which the raw material compound is mixed in a liquid medium such as water or alcohol is preferable because more uniform mixing is possible and the reactivity of the mixture can be increased in the firing step.
The mixing time varies depending on the mixing method, but it is sufficient that the raw materials are uniformly mixed at the particle level. For example, in a ball mill (wet or dry type), usually about 1 to 2 days, and in a bead mill (wet continuous method) Is usually about 0.1 to 6 hours.

  In the raw material mixing stage, it is preferable that the raw material is pulverized in parallel. As the degree of pulverization, the particle diameter of the raw material particles after pulverization is an index, but the average particle diameter (median diameter) is usually 0.4 μm or less, preferably 0.3 μm or less, more preferably 0.25 μm or less, most preferably Preferably, it is 0.2 μm or less. If the average particle size of the pulverized raw material particles is too large, the reactivity in the firing process is lowered, and the composition is difficult to homogenize. However, making particles smaller than necessary leads to an increase in the cost of pulverization, so that the average particle size is usually 0.01 μm or more, preferably 0.02 μm or more, more preferably 0.05 μm or more. It ’s fine. A means for realizing such a degree of pulverization is not particularly limited, but a wet pulverization method is preferable. Specific examples include dyno mill.

  In the present invention, the median diameter of the pulverized particles in the slurry was measured with a known laser diffraction / scattering type particle size distribution measuring apparatus with a refractive index of 1.24 and a particle diameter standard set as a volume standard. Is. In the present invention, a 0.1 wt% sodium hexametaphosphate aqueous solution was used as a dispersion medium used in the measurement, and measurement was performed after 5 minutes of ultrasonic dispersion (output 30 W, frequency 22.5 kHz). The median diameter of the spray-dried powder described later is the same as that except that the measurement was performed after ultrasonic dispersion for 0, 1, 3, and 5 minutes, respectively.

<Spray drying process>
After the wet mixing, it is then usually subjected to a drying process. The drying method is not particularly limited, but spray drying is preferable from the viewpoints of uniformity of the generated particulate matter, powder flowability, powder handling performance, and efficient production of dry particles. In this case, the spraying method is not particularly limited, and examples thereof include a method using a nozzle type atomizer (two-fluid nozzle, three-fluid nozzle, four-fluid nozzle), a rotating disk-type atomizer, and the like.

(Spray-dried powder)
In the method for producing a lithium transition metal-based compound powder such as the lithium nickel manganese cobalt-based composite oxide powder of the present invention, the slurry obtained by wet pulverizing the raw material compound and the additive is spray-dried, A powder obtained by agglomerating primary particles to form secondary particles is obtained. The spray-dried powder obtained by agglomerating primary particles to form secondary particles is a shape feature of the spray-dried powder of the present invention. Examples of the shape confirmation method include SEM observation and cross-sectional SEM observation.

  The median diameter of the powder obtained by spray drying, which is also a firing precursor of lithium transition metal based compound powder such as lithium nickel manganese cobalt based composite oxide powder of the present invention (in this case, measured without applying ultrasonic dispersion) The value is usually 15 μm or less, more preferably 12 μm or less, still more preferably 9 μm or less, and most preferably 7 μm or less. However, since it tends to be difficult to obtain a too small particle size, it is usually 3 μm or more, preferably 5 μm or more, more preferably 6 μm or more. In the case of producing a particulate material by the spray drying method, the particle size can be controlled by appropriately selecting the spray format, the pressurized gas flow supply rate, the slurry supply rate, the drying temperature, and the like.

  That is, for example, a powder obtained by spray drying a slurry in which a lithium compound, a nickel compound, a manganese compound, a cobalt compound, and an additive that suppresses grain growth and sintering during firing are dispersed in a liquid medium. In producing lithium transition metal-based compound powder such as lithium nickel manganese cobalt-based composite oxide powder by firing, the slurry viscosity during spray drying is V (cp), the slurry supply amount is S (L / min), When the gas supply amount is G (L / min), spraying is performed under the conditions that the slurry viscosity V is 50 cp ≦ V ≦ 4000 cp and the gas-liquid ratio G / S is 500 ≦ G / S ≦ 10000. Dry.

  If the slurry viscosity V (cp) is too low, it may be difficult to obtain a powder obtained by agglomerating primary particles to form secondary particles. If the slurry viscosity V (cp) is too high, the supply pump may fail or the nozzle may be blocked. is there. Therefore, the slurry viscosity V (cp) is usually 50 cp or more as a lower limit, preferably 100 cp or more, more preferably 300 cp or more, most preferably 500 cp, and the upper limit is usually 4000 cp or less, preferably 3500 cp or less. Is 3000 cp or less, most preferably 2500 cp or less.

  Further, when the gas-liquid ratio G / S is lower than the lower limit, the secondary particle size is likely to be coarsened or the drying property is liable to be lowered, and when it exceeds the upper limit, the productivity may be lowered. Therefore, the gas-liquid ratio G / S is usually 500 or more, preferably 800 or more, more preferably 1000 or more, most preferably 1500 or more as the lower limit, and usually 10,000 or less, preferably 9000 or less, as the upper limit. Preferably it is 8000 or less, most preferably 7500 or less.

  The slurry supply amount S and the gas supply amount G are appropriately set according to the viscosity of the slurry used for spray drying, the specifications of the spray drying apparatus used, and the like.

  In the method of the present invention, the above-mentioned gas-liquid ratio G / S is satisfied by controlling the slurry supply amount and gas supply amount that meet the above-mentioned slurry viscosity V (cp) and that are suitable for the specifications of the spray drying apparatus to be used. Spray drying may be performed within a range, and other conditions are appropriately set according to the type of apparatus to be used, but it is preferable to select the following conditions.

  That is, spray drying of the slurry is usually 50 ° C. or higher, preferably 70 ° C. or higher, more preferably 120 ° C. or higher, most preferably 140 ° C. or higher, usually 300 ° C. or lower, preferably 250 ° C. or lower, more preferably 200 ° C. It is preferable to carry out the reaction at a temperature of ℃ or less, most preferably 180 ℃ or less. If this temperature is too high, the resulting granulated particles may have a lot of hollow structures, which may reduce the packing density of the powder. On the other hand, if it is too low, problems such as powder sticking and blockage due to moisture condensation at the powder outlet may occur.

  In addition, the spray-dried powder of lithium transition metal-based compound powder such as lithium nickel manganese cobalt-based composite oxide powder according to the present invention is characterized by weak cohesion between primary particles. This can be confirmed by examining the change in median diameter with dispersion. Here, the upper limit of the median diameter of spray-dried particles when measured after applying ultrasonic dispersion “Ultra Sonic” (output 30 W, frequency 22.5 kHz) for 5 minutes is usually 4 μm or less, preferably 3.5 μm or less. More preferably, it is 3 μm or less, more preferably 2.5 μm or less, most preferably 2 μm or less, and the lower limit is usually 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, most preferably It is 0.2 μm or more. Lithium transition metal compound particles calcined using spray-dried particles having a median diameter after ultrasonic dispersion larger than the above value have few voids between the particles, and the load characteristics are not improved. On the other hand, lithium transition metal compound particles fired using spray-dried particles whose median diameter after ultrasonic dispersion is smaller than the above values have too many voids between the particles, resulting in decreased bulk density, There is a possibility that problems such as worsening may occur.

  The bulk density of the spray-dried powder of the lithium transition metal-based compound powder such as the lithium nickel manganese cobalt composite oxide powder of the present invention is usually 0.1 g / cc or more, preferably 0.3 g / cc or more. Preferably it is 0.5 g / cc or more, most preferably 0.7 g / cc or more. Below this lower limit, there is a possibility of adversely affecting powder filling properties and powder handling, and is usually 1.7 g / cc or less, preferably 1.6 g / cc or less, more preferably 1.5 g / cc. Hereinafter, it is most preferably 1.4 g / cc or less. The bulk density exceeding this upper limit is preferable for powder filling properties and powder handling, but the specific surface area may be too low, and the reactivity in the firing step may be reduced.

In addition, when the powder obtained by spray drying has a small specific surface area, the reactivity between the raw material compounds is reduced in the next firing step, so as described above, the starting material is pulverized before spray drying, etc. It is preferable that the specific surface area be as high as possible by this means. On the other hand, an excessive increase in specific surface area is not only industrially disadvantageous but also may result in failure to obtain a lithium transition metal compound such as the lithium nickel manganese cobalt composite oxide of the present invention. Accordingly, the spray-dried powder thus obtained has a BET specific surface area of usually 10 m ² / g or more, preferably 20 m ² / g or more, more preferably 30 m ² / g or more, and most preferably 50 m ² / g or more. In general, it is preferably 100 m ² / g or less, preferably 80 m ² / g or less, more preferably 70 m ² / g or less, and most preferably 65 m ² / g or less.

<Baking process>
The firing precursor thus obtained is then fired.
Here, in the present invention, the “firing precursor” means a precursor of a lithium transition metal compound such as a lithium nickel manganese cobalt composite oxide before firing obtained by treating a spray-dried powder. For example, the above spray-dried powder may contain a compound that generates or sublimates decomposition gas during the above-described firing to form voids in the secondary particles, and serves as a firing precursor.

  This firing condition depends on the composition and the lithium compound raw material to be used, but as a tendency, if the firing temperature is too high, primary particles grow excessively, sintering between particles proceeds too much, and the specific surface area is small. Too much. On the other hand, if it is too low, heterogeneous phases are mixed, and the lattice distortion increases without developing the crystal structure. Moreover, the specific surface area becomes too large. Accordingly, the firing temperature is usually 700 ° C. or higher. However, in the production of the lithium nickel manganese cobalt composite oxide powder having the composition represented by the composition formulas (I) and (II), it is usually 970 ° C. or higher. Preferably, it is 975 ° C or higher, more preferably 980 ° C or higher, most preferably 990 ° C or higher, usually 1200 ° C or lower, preferably 1175 ° C or lower, more preferably 1150 ° C or lower, most preferably 1125 ° C or lower. is there.

  For firing, for example, a box furnace, a tubular furnace, a tunnel furnace, a rotary kiln or the like can be used. The firing process is usually divided into three parts: temperature increase, maximum temperature retention, and temperature decrease. The second maximum temperature holding portion is not necessarily limited to one time, and may include two or more stages depending on the purpose, which means that aggregation is eliminated to the extent that secondary particles are not destroyed. The temperature raising, maximum temperature holding, and temperature lowering steps may be repeated twice or more with a crushing step or a crushing step meaning crushing to primary particles or even fine powder.

  In the temperature raising step, the temperature in the furnace is usually raised at a temperature raising rate of 1 ° C./min to 10 ° C./min. Even if this rate of temperature rise is too slow, it takes time and is industrially disadvantageous. However, if it is too fast, the furnace temperature does not follow the set temperature depending on the furnace. The rate of temperature rise is preferably 2 ° C./min or more, more preferably 3 ° C./min or more, preferably 7 ° C./min or less, more preferably 5 ° C./min or less.

  Although the holding time in the maximum temperature holding step varies depending on the temperature, it is usually 30 minutes or more, preferably 1 hour or more, more preferably 3 hours or more, most preferably 5 hours or more within the above-mentioned temperature range, and 50 Time or less, preferably 25 hours or less, more preferably 20 hours or less, and most preferably 15 hours or less. If the firing time is too short, it becomes difficult to obtain a lithium transition metal-based compound powder with good crystallinity, and it is not practical to be too long. If the firing time is too long, it will be disadvantageous because it will be necessary to crush afterwards or it will be difficult to crush.

  In the temperature lowering step, the temperature in the furnace is normally decreased at a temperature decreasing rate of 0.1 ° C./min to 10 ° C./min. If the temperature lowering rate is too slow, it takes time and is industrially disadvantageous, but if it is too fast, the uniformity of the target product tends to be lost or the deterioration of the container tends to be accelerated. The temperature lowering rate is preferably 1 ° C./min or more, more preferably 3 ° C./min or more, preferably 7 ° C./min or less, more preferably 5 ° C./min or less.

  Since the firing atmosphere has an appropriate oxygen partial pressure region depending on the composition of the lithium transition metal-based compound powder to be obtained, appropriate various gas atmospheres for satisfying the oxygen partial pressure region are used. Examples of the gas atmosphere include oxygen, air, nitrogen, argon, hydrogen, carbon dioxide, and a mixed gas thereof. An oxygen-containing gas atmosphere such as air can be used for the lithium nickel manganese cobalt based composite oxide powder specifically implemented in the present invention. Usually, the atmosphere has an oxygen concentration of 1% by volume or more, preferably 10% by volume or more, more preferably 15% by volume or more, and 100% by volume or less, preferably 50% by volume or less, more preferably 25% by volume or less.

In such a production method, in order to produce the lithium transition metal-based compound powder of the present invention, for example, the lithium nickel manganese cobalt-based composite oxide powder having the specific composition, the production conditions are constant. When preparing a slurry in which a lithium compound, nickel compound, manganese compound, and cobalt compound and an additive that suppresses grain growth and sintering during firing are dispersed in a liquid medium, the mixing ratio of each compound is adjusted. By doing so, the target Li / Ni / Mn / Co molar ratio can be controlled.
According to the lithium transition metal-based compound powder of the present invention such as lithium nickel manganese cobalt-based composite oxide powder thus obtained, the capacity is high, the load characteristics such as rate and output are excellent, and the performance balance is high. A positive electrode material for a lithium secondary battery is provided.

[Positive electrode for lithium secondary battery]
The positive electrode for a lithium secondary battery of the present invention is obtained by forming a positive electrode active material layer containing a lithium transition metal compound powder for a lithium secondary battery positive electrode material of the present invention and a binder on a current collector. It is.

  The positive electrode active material layer is usually formed by mixing a positive electrode material, a binder, and a conductive material and a thickener, which are used if necessary, in a dry form into a sheet shape, and then pressing the positive electrode current collector on the positive electrode current collector. Alternatively, these materials are dissolved or dispersed in a liquid medium to form a slurry, which is applied to the positive electrode current collector and dried.

  As the material for the positive electrode current collector, metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum, and carbon materials such as carbon cloth and carbon paper are usually used. Of these, metal materials are preferable, and aluminum is particularly preferable. As for the shape, in the case of a metal material, a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punch metal, a foam metal, etc., and in the case of a carbon material, a carbon plate, a carbon thin film, a carbon cylinder Etc. Among these, metal thin films are preferable because they are currently used in industrialized products. In addition, you may form a thin film suitably in mesh shape.

  When a thin film is used as the positive electrode current collector, its thickness is arbitrary, but it is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and usually 100 mm or less, preferably 1 mm or less, more preferably 50 μm or less. The range of is preferable. If it is thinner than the above range, the strength required for the current collector may be insufficient. On the other hand, if it is thicker than the above range, the handleability may be impaired.

  The binder used in the production of the positive electrode active material layer is not particularly limited, and in the case of a coating method, any material that is stable with respect to the liquid medium used during electrode production may be used. Specific examples include polyethylene, Resin polymers such as polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, cellulose, nitrocellulose, SBR (styrene butadiene rubber), NBR (acrylonitrile butadiene rubber), fluorine rubber, isoprene rubber, butadiene rubber, ethylene・ Rubber polymers such as propylene rubber, styrene / butadiene / styrene block copolymers and hydrogenated products thereof, EPDM (ethylene / propylene / diene terpolymers), styrene / ethylene / butadiene / ethylene copolymers, Styrene / isoprene styrene bromide Copolymer and its hydrogenated thermoplastic elastomeric polymer, syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer, etc. Fluorine polymers such as soft resinous polymers, polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymers, ion conductivity of alkali metal ions (especially lithium ions) And a polymer composition having the same. In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

  The ratio of the binder in the positive electrode active material layer is usually 0.1% by weight or more, preferably 1% by weight or more, more preferably 5% by weight or more, and usually 80% by weight or less, preferably 60% by weight or less. More preferably, it is 40% by weight or less, and most preferably 10% by weight or less. If the proportion of the binder is too low, the positive electrode active material cannot be sufficiently retained and the positive electrode has insufficient mechanical strength, which may deteriorate battery performance such as cycle characteristics. Battery capacity and conductivity may be reduced.

  The positive electrode active material layer usually contains a conductive material in order to increase conductivity. There are no particular restrictions on the type, but specific examples include metal materials such as copper and nickel, graphite such as natural graphite and artificial graphite, carbon black such as acetylene black, and amorphous carbon such as needle coke. And carbon materials. In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios. The proportion of the conductive material in the positive electrode active material layer is usually 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 1% by weight or more, and usually 50% by weight or less, preferably 30%. % By weight or less, more preferably 20% by weight or less. If the proportion of the conductive material is too low, the conductivity may be insufficient, and conversely if it is too high, the battery capacity may be reduced.

  As a liquid medium for forming a slurry, it is possible to dissolve or disperse a lithium transition metal compound powder as a positive electrode material, a binder, and a conductive material and a thickener used as necessary. If it is a solvent, there is no restriction | limiting in particular in the kind, You may use either an aqueous solvent or an organic solvent. Examples of the aqueous solvent include water and alcohol. Examples of the organic solvent include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N , N-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran (THF), toluene, acetone, dimethyl ether, dimethylacetamide, hexamethylphosphalamide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, hexane, etc. be able to. In particular, when an aqueous solvent is used, a dispersant is added together with the thickener, and a slurry such as SBR is slurried. In addition, these solvents may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The content of the lithium transition metal-based compound powder of the present invention as the positive electrode material in the positive electrode active material layer is usually 10% by weight or more, preferably 30% by weight or more, more preferably 50% by weight or more, and usually 99%. .9% by weight or less, preferably 99% by weight or less. If the proportion of the lithium transition metal compound powder in the positive electrode active material layer is too large, the strength of the positive electrode tends to be insufficient, and if it is too small, the capacity may be insufficient.

  The thickness of the positive electrode active material layer is usually about 10 to 200 μm.

The positive electrode active material layer obtained by coating and drying is preferably consolidated by a roller press or the like in order to increase the packing density of the positive electrode active material.
Thus, the positive electrode for a lithium secondary battery of the present invention can be adjusted.

[Lithium secondary battery]
The lithium secondary battery of the present invention includes the above-described positive electrode for a lithium secondary battery of the present invention capable of occluding and releasing lithium, a negative electrode capable of occluding and releasing lithium, and a non-aqueous electrolyte using a lithium salt as an electrolytic salt. Is provided. Further, a separator for holding a non-aqueous electrolyte may be provided between the positive electrode and the negative electrode. In order to effectively prevent a short circuit due to contact between the positive electrode and the negative electrode, it is desirable to interpose a separator in this way.

<Negative electrode>
The negative electrode is usually configured by forming a negative electrode active material layer on a negative electrode current collector, similarly to the positive electrode.
As a material of the negative electrode current collector, a metal material such as copper, nickel, stainless steel, nickel-plated steel, or a carbon material such as carbon cloth or carbon paper is used. Among these, in the case of a metal material, a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, etc., and in the case of a carbon material, a carbon plate, a carbon thin film, a carbon cylinder, etc. are mentioned. Among these, metal thin films are preferable because they are currently used in industrialized products. In addition, you may form a thin film suitably in mesh shape. When a metal thin film is used as the negative electrode current collector, the preferred thickness range is the same as the range described above for the positive electrode current collector.

  The negative electrode active material layer includes a negative electrode active material. The negative electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions, but it can usually occlude and release lithium from the viewpoint of high safety. A carbon material is used.

  Although there is no restriction | limiting in particular as a carbon material, Graphite (graphite), such as artificial graphite and natural graphite, and the thermal decomposition thing of organic substance on various thermal decomposition conditions are mentioned. Examples of pyrolysis products of organic matter include coal-based coke, petroleum-based coke, coal-based pitch carbide, petroleum-based pitch carbide, or carbide obtained by oxidizing these pitches, needle coke, pitch coke, phenol resin, crystalline cellulose, etc. And carbon materials obtained by partially graphitizing these, furnace black, acetylene black, pitch-based carbon fibers, and the like. Among them, graphite is preferable, and particularly preferable is artificial graphite, purified natural graphite, or graphite material containing pitch in these graphites, which is manufactured by subjecting easy-graphite pitch obtained from various raw materials to high-temperature heat treatment. Therefore, those subjected to various surface treatments are mainly used. One of these carbon materials may be used alone, or two or more thereof may be used in combination.

When a graphite material is used as the negative electrode active material, the d value (interlayer distance: d ₀₀₂ ) of the lattice plane (002 plane) determined by X-ray diffraction by the Gakushin method is usually 0.335 nm or more, and usually 0.34 nm. In the following, it is preferable that the thickness is 0.337 nm or less.

  Further, the ash content of the graphite material is usually 1% by weight or less, particularly 0.5% by weight or less, and particularly preferably 0.1% by weight or less, based on the weight of the graphite material.

  Further, the crystallite size (Lc) of the graphite material determined by X-ray diffraction by the Gakushin method is usually 30 nm or more, preferably 50 nm or more, and particularly preferably 100 nm or more.

  The median diameter of the graphite material determined by the laser diffraction / scattering method is usually 1 μm or more, especially 3 μm or more, more preferably 5 μm or more, especially 7 μm or more, and usually 100 μm or less, especially 50 μm or less, more preferably 40 μm or less, especially 40 μm or less. It is preferable that it is 30 micrometers or less.

Moreover, the BET specific surface area of the graphite material is usually 0.5 m ² / g or more, preferably 0.7 m ² / g or more, more preferably 1.0 m ² / g or more, and further preferably 1.5 m ² / g. or more, and usually 25.0 m ² / g or less, preferably 20.0 m ² / g, more preferably 15.0 m ² / g or less, still more preferably 10.0 m ² / g or less.

Further, when performing Raman spectroscopy using argon laser light for graphite material, and strength _{I A} of the peak _{P A} is detected in the range of 1580～1620Cm ^-1, it is detected in the range of 1350 ^-1 that intensity ratio _I a / _{I B} of the intensity _{I B} of a peak _{P B} is what is preferably 0 to 0.5. Further, the half width of the peak _{P A} is preferably 26cm ^-1 or less, 25 cm ^-1 or less is more preferable.

In addition to the above-mentioned various carbon materials, it can also be used as a negative electrode active material of other materials capable of inserting and extracting lithium. Specific examples of negative electrode active materials other than carbon materials include metal oxides such as tin oxide and silicon oxide, nitrides such as Li _2.6 Co _0.4 N, lithium alloys such as lithium alone and lithium aluminum alloys, and the like. Can be mentioned. One of these materials other than the carbon material may be used alone, or two or more thereof may be used in combination. Moreover, you may use in combination with the above-mentioned carbon material.

  As in the case of the positive electrode active material layer, the negative electrode active material layer is usually prepared by slurrying the above-described negative electrode active material, a binder, and optionally a conductive material and a thickener in a liquid medium. It can manufacture by apply | coating to a negative electrode electrical power collector, and drying. As the liquid medium, the binder, the thickener, the conductive material, and the like that form the slurry, the same materials as those described above for the positive electrode active material layer can be used.

<Nonaqueous electrolyte>
As the non-aqueous electrolyte, for example, known organic electrolytes, polymer solid electrolytes, gel electrolytes, inorganic solid electrolytes, and the like can be used. Of these, organic electrolytes are preferable. The organic electrolytic solution is configured by dissolving a solute (electrolyte) in an organic solvent.

  Here, the type of the organic solvent is not particularly limited. For example, carbonates, ethers, ketones, sulfolane compounds, lactones, nitriles, chlorinated hydrocarbons, ethers, amines, esters, amides. A phosphoric acid ester compound or the like can be used. Typical examples include dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, propylene carbonate, ethylene carbonate, vinylene carbonate, vinyl ethylene carbonate, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 4-methyl-2- Pentanone, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methylsulfolane, acetonitrile, propionitrile Benzonitrile, butyronitrile, valeronitrile, 1,2-dichloroethane, dimethylformamide, dimethyl sulfoxide, trimethyl phosphate, triethyl phosphate, etc. Et compounds, hydrogen atoms may be partially substituted with a halogen atom. Moreover, these single or 2 or more types of mixed solvents can be used.

  The organic solvent described above preferably contains a high dielectric constant solvent in order to dissociate the electrolytic salt. Here, the high dielectric constant solvent means a compound having a relative dielectric constant of 20 or more at 25 ° C. Among the high dielectric constant solvents, it is preferable that ethylene carbonate, propylene carbonate, and compounds in which hydrogen atoms thereof are substituted with other elements such as halogen or alkyl groups are contained in the electrolytic solution. The proportion of the high dielectric constant solvent in the electrolyte is preferably 20% by weight or more, more preferably 25% by weight or more, and most preferably 30% by weight or more. If the content of the high dielectric constant solvent is less than the above range, desired battery characteristics may not be obtained.

In addition, in the organic electrolyte, a gas such as CO ₂ , N ₂ O, CO, and SO ₂ , vinylene carbonate, polysulfide S _x ^{2−, and the} like that enables efficient charge and discharge of lithium ions on the negative electrode surface You may add the additive which forms a film in arbitrary ratios. Among these additives, vinylene carbonate is particularly preferable.

  Furthermore, an additive that exhibits an effect of improving cycle life and output characteristics, such as lithium difluorophosphate, may be added to the organic electrolyte at an arbitrary ratio.

The type of the electrolytic salt is not particularly limited, and any conventionally known solute can be used. Specific examples include LiClO ₄ , LiAsF ₆ , LiPF ₆ , LiBF ₄ , LiB (C ₆ H ₅ ) ₄ , LiBOB, LiCl, LiBr, CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiC (SO ₂ CF ₃ ) ₃ , LiN (SO ₃ CF ₃ ) _{2 and the} like. Any one of these electrolytic salts may be used alone, or two or more thereof may be used in any combination and ratio.

  The lithium salt of the electrolytic salt is usually contained in the electrolytic solution so as to have a concentration of 0.5 mol / L to 1.5 mol / L. Even if the lithium salt concentration in the electrolytic solution is less than 0.5 mol / L or more than 1.5 mol / L, the electric conductivity may be lowered, and the battery characteristics may be adversely affected. The lower limit of this concentration is preferably 0.75 mol / L or more and the upper limit is 1.25 mol / L or less.

Even when a polymer solid electrolyte is used, the kind thereof is not particularly limited, and any crystalline or amorphous inorganic substance known as a solid electrolyte can be used. Examples of the crystalline inorganic solid electrolyte include LiI, Li ₃ N, Li _{1 + x} J _x Ti _2-x (PO ₄ ) ₃ (J = Al, Sc, Y, La), Li _0.5-3x RE _{0. .5 + x} TiO ₃ (RE = La, Pr, Nd, Sm) and the like. Examples of the amorphous inorganic solid electrolyte include oxide glasses such as 4.9LiI-34.1Li ₂ O-61B ₂ O ₅ and 33.3Li ₂ O-66.7SiO ₂ . Any one of these may be used alone, or two or more may be used in any combination and ratio.

<Separator>
When the above-described organic electrolyte is used as the electrolyte, a separator is interposed between the positive electrode and the negative electrode in order to prevent a short circuit between the electrodes. The material and shape of the separator are not particularly limited, but those that are stable with respect to the organic electrolyte used, have excellent liquid retention properties, and can reliably prevent short-circuiting between electrodes are preferable. Preferable examples include microporous films, sheets and nonwoven fabrics made of various polymer materials. Specific examples of the polymer material include polyolefin polymers such as nylon, cellulose acetate, nitrocellulose, polysulfone, polyacrylonitrile, polyvinylidene fluoride, polypropylene, polyethylene, and polybutene. In particular, from the viewpoint of chemical and electrochemical stability, which is an important factor for separators, polyolefin-based polymers are preferred. From the viewpoint of self-occluding temperature, which is one of the purposes of use of separators in batteries, polyethylene is preferred. Is particularly desirable.

  When using a separator made of polyethylene, it is preferable to use ultra-high molecular weight polyethylene from the viewpoint of maintaining high-temperature shape, and the lower limit of the molecular weight is preferably 500,000, more preferably 1,000,000, and most preferably 1,500,000. On the other hand, the upper limit of the molecular weight is preferably 5 million, more preferably 4 million, and most preferably 3 million. This is because if the molecular weight is too large, the fluidity becomes too low, and the pores of the separator may not close when heated.

<Battery shape>
The lithium secondary battery of the present invention is manufactured by assembling the above-described positive electrode for a lithium secondary battery of the present invention, a negative electrode, an electrolyte, and a separator used as necessary into an appropriate shape. Furthermore, other components such as an outer case can be used as necessary.

  The shape of the lithium secondary battery of the present invention is not particularly limited, and can be appropriately selected from various commonly employed shapes according to the application. Examples of commonly used shapes include a cylinder type with a sheet electrode and separator in a spiral shape, a cylinder type with an inside-out structure combining a pellet electrode and a separator, and a coin type with stacked pellet electrodes and a separator. Can be mentioned. The method for assembling the battery is not particularly limited, and can be appropriately selected from various commonly used methods according to the shape of the target battery.

  The general embodiment of the lithium secondary battery of the present invention has been described above. However, the lithium secondary battery of the present invention is not limited to the above-described embodiment, and various modifications are possible as long as the gist thereof is not exceeded. Can be implemented.

  The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

[Measurement method of physical properties]
The physical properties and the like of lithium transition metal-based compound powders produced in each Example and Comparative Example described below were measured as follows.

<Composition (Li / Ni / Mn / Co)>
It was determined by ICP-AES analysis.

<Quantification of additive elements (Mo, W, Nb, B, Sn)>
It was determined by ICP-AES analysis.

<Composition analysis of primary particle surface by X-ray photoelectron spectroscopy (XPS)>
The measurement was performed under the following conditions using an X-ray photoelectron spectrometer “ESCA-5700” manufactured by Physical Electronics.
X-ray source: Monochromatic AlKα
Analysis area: 0.8mm diameter Extraction angle: 65 °
Quantification method: Bls, Mn2p1 _{/ 2} , Co2p3 _{/ 2} , Ni2p3 _{/ 2} , Nb3d, Mo3d, Sn3d5 _{/ 2} , W4f Each peak area is corrected with a sensitivity coefficient.
(Surface sputtering)
Ion species: Ar
Acceleration voltage: 3 kV
Ion current: 6.6 nA (Examples 3, 4, 6, and Comparative Example 2)
4.7 nA (Examples 1, 5, 7, 8 and Comparative Examples 3 and 4)
Sputtering rate: 2.29 nm / min (in terms of SiO ₂ )
(Examples 3, 4, 6 and Comparative Example 2)
2.91 nm / min (SiO ₂ conversion)
(Examples 1, 5, 7, 8 and Comparative Examples 3, 4)

<Median diameter of secondary particles>
Measurements were made after 5 minutes of ultrasonic dispersion.

<Average primary particle size>
It calculated | required from the SEM image of 30,000 times.

<Measurement of various physical properties by mercury intrusion method>
As a measuring device by the mercury intrusion method, Autopore III9420 manufactured by Micromeritics was used. Moreover, as measurement conditions of the mercury intrusion method, measurement was performed while increasing the pressure from 3.86 kPa to 413 MPa at room temperature. The mercury surface tension value was 480 dyn / cm, and the contact angle value was 141.3 °.

<Bulk density>
4 to 10 g of the sample powder was put in a 10 ml glass graduated cylinder, and the powder packing density was obtained when tapped 200 times with a stroke of about 20 mm.

<Specific surface area>
Obtained by BET method.

<Contained carbon concentration C>
An EMIA-520 carbon sulfur analyzer manufactured by HORIBA, Ltd. was used. A sample of several tens to 100 mg was weighed into an air-baked magnetic crucible, a combustion aid was added, and carbon was extracted by combustion in a high-frequency heating furnace in an oxygen stream. CO ₂ in the combustion gas was quantified by non-dispersive infrared absorptiometry. For sensitivity calibration, 150-15 low alloy steel No. 1 (C guaranteed value: 0.469% by weight) manufactured by Japan Iron and Steel Federation was used.

<Volume resistivity>
Using a powder resistivity measurement device (Dia Instruments: Lorester GP powder low efficiency measurement system PD-41), the sample weight is 3 g, and a powder probe unit (four probe / ring electrode, electrode spacing 5.0 mm) , Electrode radius 1.0 mm, sample radius 12.5 mm), the applied voltage limiter is 90 V, the volume resistivity [Ω · cm] of the powder under various pressures is measured, and the volume resistivity under a pressure of 40 MPa is measured. The values were compared.

<Confirmation of crystal phase (layered structure), measurement of half-width FWHM (110) (018) (110) (113) Confirmation of presence / absence of heterophase peak in diffraction peak, and integral intensity of heterophase peak / original crystal phase peak and Calculation of integral intensity ratio>
It calculated | required by the powder X-ray-diffraction measurement using the CuK (alpha) ray described below. Profile fitting was performed on the (018), (110), and (113) diffraction peaks derived from the hexagonal system R-3m (No. 166) observed in each sample, and integrated intensity, integrated intensity ratio, and the like were calculated.
・ For calculation of half width and area, use diffraction pattern when measured in fixed slit mode of concentration method ・ For actual XRD measurement (example, comparative example), measure in variable slit mode, variable → fixed Data conversion is performed.-Conversion from variable to fixed is based on the following formula: intensity (fixed) = intensity (variable) / sin θ
Device name: X'Pert Pro MPD manufactured by PANallytical, Netherlands
Optical system: Concentrated optical system (optical system specification)
Incident side: Enclosed X-ray tube (CuKα)
Soller Slit (0.04 rad)
Divergence Slit (Variable Slit)
Sample stage: Rotating sample stage (Spinner)
Light receiving side: Semiconductor array detector (X'Celerator)
Ni-filter
Gonio radius: 243mm
(Measurement condition)
X-ray output (CuKα): 40 kV, 30 mA
Scanning axis: θ / 2θ
Scanning range (2θ): 10.0-75.0 °
Measurement mode: Continuous
Reading width: 0.015 °
Counting time: 99.7 sec
Automatic variable slit (Automatic-DS: 10 mm (irradiation width))
Lateral divergence mask: 10 mm (irradiation width)

<Median diameter of pulverized particles in slurry>
Using a known laser diffraction / scattering particle size distribution measuring device, the refractive index was set to 1.24, and the particle diameter standard was measured as the volume standard. Further, a 0.1 wt% aqueous solution of sodium hexametaphosphate was used as a dispersion medium, and measurement was performed after 5 minutes of ultrasonic dispersion (output 30 W, frequency 22.5 kHz).

<Median Diameter as Average Particle Diameter of Raw Material Li ₂ CO ₃ Powder>
Using a known laser diffraction / scattering particle size distribution measuring apparatus (LA-920, manufactured by Horiba, Ltd.), the refractive index was set to 1.24, and the particle diameter standard was measured as a volume standard. Further, ethyl alcohol was used as a dispersion medium, and measurement was performed after ultrasonic dispersion for 5 minutes (output 30 W, frequency 22.5 kHz).

<Physical properties of particulate powder obtained by spray drying>
The form was confirmed by SEM observation and cross-sectional SEM observation. The median diameter and 90% cumulative diameter (D ₉₀ ) as the average particle diameter are set to a refractive index of 1.24 using a known laser diffraction / scattering particle size distribution measuring device (LA-920, manufactured by Horiba, Ltd.) The particle diameter standard was measured based on the volume. Further, a 0.1 wt% sodium hexametaphosphate aqueous solution was used as a dispersion medium, and measurement was performed after 0 minutes, 1 minute, 3 minutes, and 5 minutes of ultrasonic dispersion (output 30 W, frequency 22.5 kHz). The specific surface area was determined by the BET method. The bulk density was determined as the powder packing density when 4 to 6 g of sample powder was put in a 10 ml glass graduated cylinder and tapped 200 times with a stroke of about 20 mm.

[Production of Lithium Transition Metal Compound Powder (Examples and Comparative Examples)]
Example 1
Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , CoOOH, Li ₂ WO ₄ are replaced with Li: Ni: Mn: Co: W = 1.10: 0.45: 0.45: 0.10: After weighing and mixing to a molar ratio of 0.005, pure water was added thereto to prepare a slurry. While stirring the slurry, the solid content in the slurry was pulverized to a median diameter of 0.16 μm using a circulating medium agitation type wet pulverizer.
Next, this slurry (solid content 15% by weight, viscosity 1720 cp) was spray-dried using a two-fluid nozzle type spray dryer (Okawara Kako Co., Ltd .: LT-8 type). Air was used as the drying gas at this time, the drying gas introduction amount G was 45 L / min, and the slurry introduction amount S was 6 × 10 ⁻³ L / min (gas-liquid ratio G / S = 7500). The drying inlet temperature was 150 ° C. About 15 g of particulate powder obtained by spray-drying with a spray drier is charged into an alumina crucible, fired at 1000 ° C. for 6 hours in an air atmosphere (heating rate of 3.33 ° C./min.), And then crushed. and a volume resistivity of 5.4 × 10 ⁴ Ω · cm, the carbon concentration C is 0.042 wt%, the composition is _{Li 1.114 (Ni 0.453 Mn 0.450 Co} 0.097) O 2 Lithium nickel manganese cobalt composite oxide (x = 0.097, y = 0.003, z = 0.114) having a layered structure of
When the total molar ratio of (Ni, Mn, Co) in the obtained lithium nickel manganese cobalt composite oxide powder was 1, the W content molar ratio was 0.62 mol%. The average primary particle diameter is 0.4 μm, the median diameter is 1.4 μm, the 90% cumulative diameter (D ₉₀ ) is 2.1 μm, the bulk density is 1.1 g / cc, and the BET specific surface area is 2.1 m ² / g. Furthermore, the atomic ratio of W on the primary particle surface was 9.8 times the atomic ratio of W (tungsten) for the entire particle (W / (Ni + Mn + Co). , the atomic ratio _{R 0} of W relative to the total of Co), percentage _R 0 _{/ R 10} of the total atomic ratio _{R 10} of W relative to the total of the depth 10nm from the particle surface (Ni, Mn, Co) 4 . 4.

(Example 2)
Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , CoOOH, Li ₂ WO ₄ are replaced with Li: Ni: Mn: Co: W = 1.10: 0.45: 0.45: 0.10: After weighing and mixing to a molar ratio of 0.01, pure water was added thereto to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.17 μm using a circulating medium agitation type wet pulverizer.
Next, this slurry (solid content 15% by weight, viscosity 1890 cp) was spray-dried using a two-fluid nozzle type spray dryer (Okawara Kako Co., Ltd .: LT-8 type). Air was used as the drying gas at this time, the drying gas introduction amount G was 45 L / min, and the slurry introduction amount S was 7 × 10 ⁻³ L / min (gas-liquid ratio G / S = 6429). The drying inlet temperature was 150 ° C. About 15 g of particulate powder obtained by spray-drying with a spray dryer was placed in an alumina crucible, fired at 1000 ° C. for 6 hours in an air atmosphere (heating rate of 3.33 ° C./min.), And then crushed. The volume resistivity is 4.7 × 10 ⁴ Ω · cm, the carbon concentration C is 0.030 wt%, and the composition is Li _1.139 (Ni _0.450 Mn _0.452 Co _0.098 ) O _2. Lithium nickel manganese cobalt composite oxide (x = 0.098, y = −0.002, z = 0.139) having a layered structure of
When the total molar ratio of (Ni, Mn, Co) in the obtained lithium nickel manganese cobalt composite oxide powder was 1, the W content molar ratio was 1.03 mol%. The average primary particle diameter is 0.3 μm, the median diameter is 2.2 μm, the 90% cumulative diameter (D ₉₀ ) is 3.9 μm, the bulk density is 1.0 g / cc, and the BET specific surface area is 2.9 m ² / g. Furthermore, the atomic ratio of W on the surface of the primary particles was 9.4 times the atomic ratio of W (tungsten) of the whole particle (W / (Ni + Mn + Co)).

(Example 3)
Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , CoOOH, Li ₂ MoO ₄ are mixed with Li: Ni: Mn: Co: Mo = 1.10: 0.45: 0.45: 0.10: After weighing and mixing to a molar ratio of 0.005, pure water was added thereto to prepare a slurry. While stirring the slurry, the solid content in the slurry was pulverized to a median diameter of 0.16 μm using a circulating medium agitation type wet pulverizer.
Next, this slurry (solid content 15% by weight, viscosity 1710 cp) was spray-dried using a two-fluid nozzle type spray dryer (Okawara Kako Co., Ltd .: LT-8 type). Air was used as the drying gas at this time, the drying gas introduction amount G was 45 L / min, and the slurry introduction amount S was 6 × 10 ⁻³ L / min (gas-liquid ratio G / S = 7500). The drying inlet temperature was 150 ° C. About 15 g of particulate powder obtained by spray-drying with a spray dryer is placed in an alumina crucible, fired at 1000 ° C. for 6 hours in an air atmosphere (heating temperature rate 3.33 ° C./min.), And then crushed. The volume resistivity is 3.6 × 10 ⁴ Ω · cm, the carbon concentration C is 0.027% by weight, and the composition is Li _1.124 (Ni _0.452 Mn _0.450 Co _0.098 ) O _2. Lithium nickel manganese cobalt composite oxide (x = 0.098, y = 0.002, z = 0.124) having a layered structure of
When the total molar ratio of (Ni, Mn, Co) of the obtained lithium nickel manganese cobalt composite oxide powder was 1, the Mo molar ratio was 0.48 mol%. The average primary particle diameter is 0.7 μm, the median diameter is 2.0 μm, the 90% cumulative diameter (D ₉₀ ) is 3.2 μm, the bulk density is 1.3 g / cc, and the BET specific surface area is 1.6 m ² / g. Furthermore, the atomic ratio of Mo on the primary particle surface was 21 times the atomic ratio (Mo / (Ni + Mn + Co) of Mo (molybdenum) of the entire particle. The ratio R ₀ / R ₁₀ of the atomic ratio R ₀ of Mo with respect to the sum of () and the atomic ratio R ₁₀ of the total Mo with respect to the sum of (Ni, Mn, Co) at a depth of 10 nm from the particle surface is 3.6. there were.

Example 4
Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , CoOOH, WO ₃ are mixed with Li: Ni: Mn: Co: W = 1.10: 0.45: 0.45: 0.10: 0. After weighing and mixing so that the molar ratio was 005, pure water was added thereto to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.17 μm using a circulating medium agitation type wet pulverizer.
Next, this slurry (solid content 14% by weight, viscosity 1670 cp) was spray-dried using a two-fluid nozzle type spray dryer (Okawara Kako Co., Ltd .: LT-8 type). Air was used as the drying gas at this time, the drying gas introduction amount G was 45 L / min, and the slurry introduction amount S was 6 × 10 ⁻³ L / min (gas-liquid ratio G / S = 7500). The drying inlet temperature was 150 ° C. About 15 g of particulate powder obtained by spray-drying with a spray dryer is placed in an alumina crucible, fired at 1000 ° C. for 6 hours in an air atmosphere (heating temperature rate 3.33 ° C./min.), And then crushed. The volume resistivity is 5.8 × 10 ⁴ Ω · cm, the carbon concentration C is 0.033 wt%, and the composition is Li _1.094 (Ni _0.453 Mn _0.450 Co _0.097 ) O _2. Lithium nickel manganese cobalt composite oxide (x = 0.097, y = 0.003, z = 0.094) having a layered structure of
When the total molar ratio of (Ni, Mn, Co) of the obtained lithium nickel manganese cobalt composite oxide powder was 1, the W content molar ratio was 0.51 mol%. The average primary particle diameter is 0.5 μm, the median diameter is 1.6 μm, the 90% cumulative diameter (D ₉₀ ) is 2.4 μm, the bulk density is 1.0 g / cc, and the BET specific surface area is 2.2 m ² / g. Furthermore, the atomic ratio of W on the primary particle surface was 12 times the atomic ratio of W (tungsten) for the entire particle (W / (Ni + Mn + Co). the atomic ratio _{R 0} of W relative to the total of), the ratio _R 0 _{/ R 10} of the total atomic ratio _{R 10} of W relative to the total of the depth 10nm from the particle surface (Ni, Mn, Co) in 3.3 there were.

(Example 5)
Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , CoOOH, Nb ₂ O ₅ are mixed with Li: Ni: Mn: Co: Nb = 1.10: 0.45: 0.45: 0.10: After weighing and mixing to a molar ratio of 0.005, pure water was added thereto to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.17 μm using a circulating medium agitation type wet pulverizer.
Next, this slurry (solid content 14% by weight, viscosity 1660 cp) was spray-dried using a two-fluid nozzle type spray dryer (Okawara Kako Co., Ltd .: LT-8 type). Air was used as the drying gas at this time, the drying gas introduction amount G was 45 L / min, and the slurry introduction amount S was 6 × 10 ⁻³ L / min (gas-liquid ratio G / S = 7500). The drying inlet temperature was 150 ° C. About 15 g of particulate powder obtained by spray-drying with a spray dryer was placed in an alumina crucible, fired at 1000 ° C. for 6 hours in an air atmosphere (heating rate of 3.33 ° C./min.), And then crushed. Thus, the volume resistivity is 4.4 × 10 ⁴ Ω · cm, the carbon concentration C is 0.027 wt%, and the composition is Li _1.118 (Ni _0.448 Mn _0.450 Co _0.102 ) O _2. Lithium nickel manganese cobalt composite oxide (x = 0.102, y = −0.002, z = 0.118) having a layered structure of
When the total molar ratio of (Ni, Mn, Co) in the obtained lithium nickel manganese cobalt composite oxide powder was 1, the Nb content molar ratio was 0.48 mol%. The average primary particle diameter is 0.6 μm, the median diameter is 2.0 μm, the 90% cumulative diameter (D ₉₀ ) is 3.3 μm, the bulk density is 1.2 g / cc, and the BET specific surface area is 1.9 m ² / g. Further, the atomic ratio of Nb on the primary particle surface was 8.8 times the atomic ratio of Nb (niobium) of the whole particle (Nb / (Ni + Mn + Co). , the atomic ratio _{R 0} of Nb to the total of Co), percentage _R 0 _{/ R 10} of the total atomic ratio _{R 10} of Nb to the total of the depth 10nm from the particle surface (Ni, Mn, Co) 3 . 6.

(Example 6)
Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , CoOOH, WO ₃ are mixed with Li: Ni: Mn: Co: W = 1.12: 0.45: 0.45: 0.10: 0. After weighing and mixing to a molar ratio of 01, pure water was added thereto to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.23 μm using a circulating medium agitation type wet pulverizer.
Next, this slurry (solid content 16.5% by weight, viscosity 1650 cp) was spray-dried using a four-fluid nozzle type spray dryer (manufactured by Fujisaki Electric Co., Ltd .: MDP-50 type). At this time, air was used as the dry gas, the dry gas introduction amount G was 1600 L / min, and the slurry introduction amount S was 780 mL / min (gas-liquid ratio G / S = 2051). The drying inlet temperature was 200 ° C. About 370 g of particulate powder obtained by spray drying with a spray dryer is charged into an alumina square bowl and fired at 1000 ° C. for 2 hours in an air atmosphere (temperature increase rate: about 1.7 ° C./min., Temperature decrease rate) : About 3.3 ° C./min.), And then classified using a Puffer footer (manufactured by Tsukasa Kogyo Co., Ltd.) with a 45 μm mesh to obtain a lithium nickel manganese cobalt composite oxide powder.
The lithium nickel manganese cobalt composite oxide powder, the composition is _{Li (Li 0.053 Ni 0.425 Mn 0.427} Co 0.095) Lithium nickel manganese cobalt composite oxide having a layered structure of _{O 2} (x = 0.100, y = −0.002, z = 0.111), and when the total molar ratio of (Ni, Mn, Co) is 1, the W content molar ratio was 1.01 mol%. It was. The average primary particle diameter is 0.2 μm, the median diameter is 2.7 μm, the 90% cumulative diameter (D ₉₀ ) is 4.9 μm, the bulk density is 1.0 g / cc, and the BET specific surface area is 2.8 m ² / g, the volume resistivity was 6.3 × 10 ⁴ Ω · cm, and the carbon concentration C was 0.031 wt%. Further, the atomic ratio of W on the primary particle surface was 7.8 times the atomic ratio of W (tungsten) of the whole particle (W / (Ni + Mn + Co)). Further, in the particle outermost surface (Ni, Mn, Co) and the atomic ratio _{R 0} of W relative to the total of, at a depth of 10nm from the particle surface (Ni, Mn, Co) to the total atomic ratio _{R 10} of W to the sum of The ratio R ₀ / R _{10 of} was 4.5.

(Example 7)
Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , CoOOH, WO ₃ are mixed with Li: Ni: Mn: Co: W = 1.15: 0.475: 0.475: 0.05: 0. After weighing and mixing so as to have a molar ratio of 015, pure water was added thereto to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.27 μm using a circulating medium agitation type wet pulverizer.
Next, this slurry (solid content 15% by weight, viscosity 840 cp) was spray-dried using a two-fluid nozzle type spray dryer (Okawara Kako Co., Ltd .: LT-8 type). Air was used as the drying gas at this time, the drying gas introduction amount G was 45 L / min, and the slurry introduction amount S was 6 × 10 ⁻³ L / min (gas-liquid ratio G / S = 7500). The drying inlet temperature was 150 ° C. About 15 g of particulate powder obtained by spray-drying with a spray dryer is placed in an alumina crucible, fired at 1050 ° C. for 6 hours in an air atmosphere (heating rate of 3.33 ° C./min.), And then crushed. to a volume resistivity of 1.5 × 10 ⁵ Ω · cm, the carbon concentration is 0.063 wt%, the composition is _{Li 1.149 (Ni 0.472 Mn 0.480 Co} 0.048) O 2 Lithium nickel manganese cobalt composite oxide (x = 0.048, y = −0.008, z = 0.149) was obtained.
When the total molar ratio of (Ni, Mn, Co) of the obtained lithium nickel manganese cobalt composite oxide powder was 1, the W molar ratio was 1.47 mol%. The average primary particle diameter is 0.4 μm, the median diameter is 3.4 μm, the 90% cumulative diameter (D ₉₀ ) is 5.8 μm, the bulk density is 1.0 g / cc, and the BET specific surface area is 2.5 m ² / g. Furthermore, the atomic ratio of W on the primary particle surface was 11 times the atomic ratio of W (tungsten) of the whole particle (W / (Ni + Mn + Co)). Further, in the particle outermost surface (Ni, Mn, Co) and the atomic ratio _{R 0} of W relative to the total of, at a depth of 10nm from the particle surface (Ni, Mn, Co) to the total atomic ratio _{R 10} of W to the sum of The ratio R ₀ / R ₁₀ was 4.9.

(Example 8)
It was produced in the same manner as in Example 7 except that the firing temperature was 1100 ° C., the volume resistivity was 4.7 × 10 ⁵ Ω · cm, the carbon concentration was 0.056% by weight, and the composition was Li _1.134 ( Ni _0.472 Mn _0.480 Co _0.048) lithium nickel manganese cobalt composite oxide of _{O 2 (x = 0.048, y} = -0.008, was obtained z = 0.134).
When the total molar ratio of (Ni, Mn, Co) of the obtained lithium nickel manganese cobalt composite oxide powder was 1, the W molar ratio was 1.47 mol%. The average primary particle size is 0.4 μm, the median diameter is 3.9 μm, the 90% cumulative diameter (D ₉₀ ) is 6.3 μm, the bulk density is 1.2 g / cc, and the BET specific surface area is 2.0 m ² / g. Furthermore, the atomic ratio of W on the primary particle surface was 14 times the atomic ratio of W (tungsten) of the whole particle (W / (Ni + Mn + Co)). Further, in the particle outermost surface (Ni, Mn, Co) and the atomic ratio _{R 0} of W relative to the total of, at a depth of 10nm from the particle surface (Ni, Mn, Co) to the total atomic ratio _{R 10} of W to the sum of The ratio R ₀ / R ₁₀ of 4.8 was 4.8.

(Comparative Example 1)
Weigh Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , and CoOOH so that the molar ratio of Li: Ni: Mn: Co = 1.10: 0.45: 0.45: 0.10 After mixing, pure water was added to prepare a slurry. While stirring the slurry, the solid content in the slurry was pulverized to a median diameter of 0.16 μm using a circulating medium agitation type wet pulverizer.
Next, this slurry (solid content 13 wt%, viscosity 1350 cp) was spray-dried using a two-fluid nozzle type spray dryer (Okawara Kako Co., Ltd .: LT-8 type). Air was used as the drying gas at this time, the drying gas introduction amount G was 45 L / min, and the slurry introduction amount S was 6 × 10 ⁻³ L / min (gas-liquid ratio G / S = 7500). The drying inlet temperature was 150 ° C. About 15 g of particulate powder obtained by spray-drying with a spray dryer is placed in an alumina crucible, fired at 1000 ° C. for 6 hours in an air atmosphere (heating temperature rate 3.33 ° C./min.), And then crushed. The volume resistivity is 2.7 × 10 ⁴ Ω · cm, the carbon concentration C is 0.023 wt%, and the composition is Li _1.096 (Ni _0.458 Mn _0.444 Co _0.098 ) O _2. Of lithium nickel manganese cobalt composite oxide (x = 0.098, y = 0.016, z = 0.096) was obtained. The average primary particle diameter is 0.6 μm, the median diameter is 3.0 μm, the 90% cumulative diameter (D ₉₀ ) is 5.1 μm, the bulk density is 1.2 g / cc, and the BET specific surface area is 1.7 m ² / g. Met.

(Comparative Example 2)
Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , CoOOH, Li ₂ WO ₄ are replaced with Li: Ni: Mn: Co: W = 1.10: 0.45: 0.45: 0.10: After weighing and mixing to a molar ratio of 0.02, pure water was added thereto to prepare a slurry. While stirring the slurry, the solid content in the slurry was pulverized to a median diameter of 0.13 μm using a circulating medium agitation type wet pulverizer.
Next, this slurry (solid content 15% by weight, viscosity 1910 cp) was spray-dried using a two-fluid nozzle type spray dryer (Okawara Kako Co., Ltd .: LT-8 type). Air was used as the drying gas at this time, the drying gas introduction amount G was 45 L / min, and the slurry introduction amount S was 7 × 10 ⁻³ L / min (gas-liquid ratio G / S = 6429). The drying inlet temperature was 150 ° C. About 15 g of particulate powder obtained by spray-drying with a spray dryer was placed in an alumina crucible, fired at 1000 ° C. for 6 hours in an air atmosphere (heating rate of 3.33 ° C./min.), And then crushed. The volume resistivity is 1.1 × 10 ⁴ Ω · cm, the carbon concentration C is 0.050 wt%, and the composition is Li _1.124 (Ni _0.457 Mn _0.446 Co _0.097 ) O _2. Lithium nickel manganese cobalt composite oxide (x = 0.097, y = 0.122, z = 0.124) was obtained. Further, when the total molar ratio of (Ni, Mn, Co) was 1, the W molar ratio was 2.06 mol%. The average primary particle diameter is 0.2 μm, the median diameter is 0.8 μm, the 90% cumulative diameter (D ₉₀ ) is 1.3 μm, the bulk density is 0.9 g / cc, and the BET specific surface area is 3.8 m ² / g. Met. Furthermore, the atomic ratio of W on the primary particle surface was 6.0 times the atomic ratio of W (tungsten) for the entire particle (W / (Ni + Mn + Co)).

(Comparative Example 3)
Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , CoOOH, Li ₂ B ₄ O ₇ are mixed with Li: Ni: Mn: Co: B = 1.10: 0.45: 0.45: 0. After weighing and mixing to a molar ratio of 10: 0.005, pure water was added to prepare a slurry. While stirring the slurry, the solid content in the slurry was pulverized to a median diameter of 0.16 μm using a circulating medium agitation type wet pulverizer.
Next, this slurry (solid content 15% by weight, viscosity 1460 cp) was spray-dried using a two-fluid nozzle type spray dryer (Okawara Kako Co., Ltd .: LT-8 type). Air was used as the drying gas at this time, the drying gas introduction amount G was 45 L / min, and the slurry introduction amount S was 6 × 10 ⁻³ L / min (gas-liquid ratio G / S = 7500). The drying inlet temperature was 150 ° C. About 15 g of particulate powder obtained by spray-drying with a spray dryer was placed in an alumina crucible, fired at 1000 ° C. for 6 hours in an air atmosphere (heating rate of 3.33 ° C./min.), And then crushed. The volume resistivity is 5.3 × 10 ⁴ Ω · cm, the carbon concentration C is 0.047 wt%, and the composition is Li _1.096 (Ni _0.450 Mn _0.451 Co _0.099 ) O _2. Lithium nickel manganese cobalt composite oxide (x = 0.099, y = −0.001, z = 0.096) was obtained. When the total molar ratio of (Ni, Mn, Co) was 1, the B molar ratio was 0.24 mol%. The average primary particle diameter is 1.0 μm, the median diameter is 5.9 μm, the 90% cumulative diameter (D ₉₀ ) is 8.9 μm, the bulk density is 1.8 g / cc, and the BET specific surface area is 0.8 m ² / g. Met. Furthermore, the atomic ratio of B on the primary particle surface was 213 times the atomic ratio of B (boron) of the whole particle (B / (Ni + Mn + Co)).

(Comparative Example 4)
Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , CoOOH, SnO ₂ are mixed with Li: Ni: Mn: Co: Sn = 1.10: 0.45: 0.45: 0.10: 0. After weighing and mixing so that the molar ratio was 005, pure water was added thereto to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.17 μm using a circulating medium agitation type wet pulverizer.
Next, this slurry (solid content 14% by weight, viscosity 1580 cp) was spray-dried using a two-fluid nozzle type spray dryer (Okawara Kako Co., Ltd .: LT-8 type). Air was used as the drying gas at this time, the drying gas introduction amount G was 45 L / min, and the slurry introduction amount S was 6 × 10 ⁻³ L / min (gas-liquid ratio G / S = 7500). The drying inlet temperature was 150 ° C. About 15 g of particulate powder obtained by spray-drying with a spray dryer is placed in an alumina crucible, fired at 1000 ° C. for 6 hours in an air atmosphere (heating temperature rate 3.33 ° C./min.), And then crushed. The volume resistivity is 3.1 × 10 ⁴ Ω · cm, the carbon concentration C is 0.028 wt%, and the composition is Li _1.083 (Ni _0.448 Mn _0.456 Co _0.096 ) O _2. Lithium nickel manganese cobalt composite oxide (x = 0.096, y = −0.009, z = 0.083) was obtained. When the total molar ratio of (Ni, Mn, Co) was 1, the Sn molar ratio was 0.49 mol%. The average primary particle diameter is 0.5 μm, the median diameter is 3.8 μm, the 90% cumulative diameter (D ₉₀ ) is 6.2 μm, the bulk density is 1.1 g / cc, and the BET specific surface area is 1.7 m ² / g. Met. Furthermore, the atomic ratio of Sn on the surface of the primary particles was 3.5 times the atomic ratio of Sn (tin) of the whole particle (Sn / (Ni + Mn + Co)).

(Comparative Example 5)
Weigh Li ₂ CO ₃ , Ni (OH) ₂ , Mn ₃ O ₄ , and CoOOH so that the molar ratio is Li: Ni: Mn: Co = 1.15: 0.475: 0.475: 0.05. After mixing, pure water was added to prepare a slurry. While stirring this slurry, the solid content in the slurry was pulverized to a median diameter of 0.25 μm using a circulating medium agitation type wet pulverizer.
Next, this slurry (solid content 15% by weight, viscosity 1450 cp) was spray-dried using a two-fluid nozzle type spray dryer (Okawara Kako Co., Ltd .: LT-8 type). Air was used as the drying gas at this time, the drying gas introduction amount G was 45 L / min, and the slurry introduction amount S was 7 × 10 ⁻³ L / min (gas-liquid ratio G / S = 6429). The drying inlet temperature was 150 ° C. About 15 g of particulate powder obtained by spray-drying with a spray dryer was charged into an alumina crucible, fired at 1050 ° C. for 6 hours in an air atmosphere (heating rate of 3.33 ° C./min.), And then crushed. The volume resistivity is 2.1 × 10 ⁴ Ω · cm, the carbon concentration is 0.037 wt%, and the composition is Li _1.106 (Ni _0.481 Mn _0.471 Co _0.048 ) O ₂ . Lithium nickel manganese cobalt composite oxide (x = 0.048, y = 0.011, z = 0.106) was obtained. The obtained lithium nickel manganese cobalt composite oxide powder has an average primary particle size of 1.5 μm, a median diameter of 6.2 μm, a 90% cumulative diameter (D ₉₀ ) of 9.5 μm, and a bulk density of 1.9 g / The cc and BET specific surface area was 0.8 m ² / g.

  Tables 1, 2, 3, and 4 show the compositions and physical property values of the lithium transition metal compound powders produced in the above Examples and Comparative Examples. Table 5 shows the powder properties of the spray-dried body, which is a firing precursor.

  Moreover, the pore distribution curve of the lithium nickel manganese cobalt complex oxide powder manufactured in Examples 1-8 and Comparative Examples 1-5 is shown in FIGS. 1-13, respectively, and SEM image (photograph) (magnification x10) , 000) are shown in FIGS. 14 to 26, and powder X-ray diffraction patterns are shown in FIGS. Moreover, the graph which shows the density | concentration distribution of the addition element from the particle | grain surface of the lithium nickel manganese cobalt complex oxide powder manufactured in Example 1, 3-8 and Comparative Examples 2-4 to the depth direction is shown in FIGS. Respectively.

[Production and evaluation of batteries]
Using the lithium transition metal-based compound powders produced in Examples 1 to 8 and Comparative Examples 1 to 5 described above as positive electrode materials (positive electrode active materials), lithium secondary batteries were produced by the following method and evaluated. went.

(1) Rate test:
A mortar obtained by weighing 75% by weight of each of the lithium transition metal compound powders produced in Examples 1 to 8 and Comparative Examples 1 to 5, 20% by weight of acetylene black, and 5% by weight of polytetrafluoroethylene powder. Were mixed thoroughly and made into a thin sheet, and punched out using a 9 mmφ punch. At this time, the total weight was adjusted to about 8 mg. This was pressure-bonded to an aluminum expanded metal to obtain a 9 mmφ positive electrode.

This 9 mmφ positive electrode is used as a test electrode, a lithium metal plate is used as a counter electrode, and LiPF ₆ is added to a solvent of EC (ethylene carbonate): DMC (dimethyl carbonate): EMC (ethyl methyl carbonate) = 3: 3: 4 (volume ratio). Using an electrolytic solution dissolved at 1 mol / L, a coin-type cell was assembled using a porous polyethylene film having a thickness of 25 μm as a separator.

For the obtained coin-type cell, in the initial two cycles, the charging upper limit voltage was set to 4.4 V, and constant current / constant voltage charging (current density: up to 4.4 V at 0.137 mA / cm ² (0.1 C)) After constant current charging, constant voltage charging was performed until 0.01 C was reached, and then the discharge lower limit voltage was set to 3.0 V, and constant current discharging (current density 0.137 mA / cm ² (0.1 C)) was performed. went. Furthermore, in the 3rd to 10th cycles, 0.2C constant current / constant voltage charging (constant current charging up to 4.4V at 0.2C and then constant voltage charging to 0.01C), 0.1C, 0.2C , 0.5C, 1C, 3C, 5C, 7C, and 9C constant current discharges were tested. However, the current corresponding to 1 C was assumed to be 150 mA per 1 g of active material. 0.1C discharge capacity (mAh / g) at the first cycle (initial discharge capacity) at this time, 0.1C discharge capacity (mAh / g) at the third cycle (discharge capacity at the third cycle) [a]), 6 1C discharge capacity (mAh / g) at the cycle (6th cycle discharge capacity [b]) and 9C discharge capacity (mAh / g) at the 10th cycle) (discharge capacity [c] at the 10th cycle) Are shown in Table 6.

  In addition, as an acceptance criterion of the examples, the initial discharge capacity in the first cycle is 172 mAh / g or more, the 0.1C discharge capacity in the third cycle is 172 mAh / g or more, and the 1C discharge capacity in the sixth cycle is 160 mAh / g. As described above, the 9C discharge capacity at the 10th cycle was set to 120 mAh / g or more.

(2) Low temperature load characteristic test:
The layered lithium nickel manganese cobalt composite oxide powders prepared in Examples 1 to 8 and Comparative Examples 1 to 5 were weighed in a ratio of 75% by weight, acetylene black 20% by weight, and polytetrafluoroethylene powder 5% by weight. Were mixed thoroughly in a mortar, and the thin sheet was punched out using 9 mmφ and 12 mmφ punches. At this time, the total weight was adjusted to about 8 mg and about 18 mg, respectively. This was pressure-bonded to an aluminum expanded metal to obtain positive electrodes of 9 mmφ and 12 mmφ. Those having a diameter of 9 mm are referred to as “positive electrode A”, and those having a diameter of 12 mm are referred to as “positive electrode B”.

9 mmφ positive electrode A is used as a test electrode, a lithium metal plate is used as a counter electrode, and LiPF ₆ is added to a solvent of EC (ethylene carbonate): DMC (dimethyl carbonate): EMC (ethyl methyl carbonate) = 3: 3: 4 (volume ratio). Using an electrolytic solution dissolved at 1 mol / L, a coin-type cell was assembled using a porous polyethylene film having a thickness of 25 μm as a separator.

The obtained coin-type cell was subjected to a constant current / constant voltage charge of 0.2 mA / cm ² , that is, a reaction for releasing lithium ions from the positive electrode at an upper limit of 4.2 V. Subsequently, 0.2 mA / cm ² , the initial charge capacity per unit weight of the positive electrode active material was Qs (C) [mAh / g], and the initial discharge capacity was Qs (D) [mAh / g].

Graphite powder having an average particle diameter of 8 to 10 μm (d ₀₀₂ = 3.35 Å) was used as the negative electrode active material, and polyvinylidene fluoride was used as the binder, and these were weighed at a ratio of 92.5: 7.5. Were mixed in an N-methylpyrrolidone solution to obtain a negative electrode mixture slurry. This slurry was applied to one side of a 20 μm thick copper foil, dried to evaporate the solvent, punched to 12 mmφ, and pressed at 0.5 ton / cm ² (49 MPa) to make negative electrode B . At this time, the amount of the negative electrode active material on the electrode was adjusted to about 7 mg.

The negative electrode B is used as a test electrode, a battery cell is assembled using lithium metal as a counter electrode, and lithium ions are occluded in the negative electrode by a constant current-constant voltage method (cut current 0.05 mA) of 0.2 mA / cm ² -3 mV. The initial storage capacity per unit weight of the negative electrode active material when the test was performed at the lower limit of 0 V was defined as Qf [mAh / g].

The positive electrode B and the negative electrode B were combined, a test battery was assembled using a coin cell, and the battery performance was evaluated. That is, the above-described positive electrode B prepared is placed on the positive electrode can of the coin cell, and a porous polyethylene film having a thickness of 25 μm is placed thereon as a separator and pressed with a polypropylene gasket, followed by EC as a non-aqueous electrolyte. (Ethylene carbonate): DMC (dimethyl carbonate): EMC (ethyl methyl carbonate) = 3: 3 (volume ratio) A solution obtained by dissolving LiPF ₆ at 1 mol / L was added to a can. Then, the separator was sufficiently infiltrated, and then the negative electrode B described above was placed, the negative electrode can was placed and sealed, and a coin-type lithium secondary battery was produced. At this time, the balance between the weight of the positive electrode active material and the weight of the negative electrode active material was set so as to satisfy the following expression.
Positive electrode active material weight [g] / Negative electrode active material weight [g]
= (Qf [mAh / g] /1.2) Qs (C) [mAh / g]

In order to measure the low-temperature load characteristics of the battery thus obtained, the hourly rate current value of the battery, that is, 1C was set as shown in the following equation, and the following tests were performed.
1C [mA] = Qs (D) × positive electrode active material weight [g] / h

First, a constant current 0.2C charge / discharge cycle and a constant current 1C charge / discharge cycle were performed at room temperature. The upper limit of charging was 4.1 V, and the lower limit voltage was 3.0 V. Next, when a coin cell adjusted to a charging depth of 40% is held in a low temperature atmosphere of −30 ° C. for 1 hour or longer by 1/3 C constant current charging / discharging and then discharged for 10 seconds at a constant current of 0.5 C [mA]. Assuming that the voltage after 10 seconds is V [mV] and the voltage before discharge is V ₀ [mV], the resistance value R [Ω] is calculated from the following equation as ΔV = V−V ₀ .
R [Ω] = ΔV [mV] /0.5C [mA]

  In Table 6, the resistance value measured with the battery which used the lithium nickel manganese cobalt complex oxide of Examples 1-8 and Comparative Examples 1-5 as a positive electrode active material, respectively is shown. The smaller the resistance value, the better the low temperature load characteristic. In addition, it set that this resistance value was 480 (ohm) or less as a pass criterion of an Example.

  From Table 6, it can be seen that according to the lithium nickel manganese cobalt composite oxide powder for a lithium secondary battery positive electrode material of the present invention, a lithium secondary battery excellent in load characteristics can be realized.

Claims (28)

  The main component is a lithium transition metal compound having a function capable of inserting / extracting lithium ions, and the main component material is mainly composed of at least one additive for suppressing grain growth and sintering during firing. For a lithium secondary battery positive electrode material, characterized by being added after being added in a proportion of 0.01 mol% or more and less than 2 mol% with respect to the total molar amount of transition metal elements in the component raw material Lithium transition metal compound powder.   2. The oxide according to claim 1, wherein the additive is an oxide containing at least one element selected from Mo, W, Nb, Ta, and Re (hereinafter referred to as “additive element”). Lithium transition metal compound powder for lithium secondary battery positive electrode material.   The atomic ratio of the total of the additive elements to the total of Li and metal elements other than the additive elements on the surface portion of the primary particles is 5 times or more of the atomic ratio of the whole particles. Lithium transition metal compound powder for lithium secondary battery positive electrode material. The additive contains a metal element (hereinafter referred to as “additive element”), the atomic ratio R ₀ of the total of the additive element to the total of Li and the metal elements other than the additive element on the outermost surface of the particle, and the particle surface The ratio R ₀ / R ₁₀ with respect to the total atomic ratio R ₁₀ of the additive element to the total of Li and a metal element other than the additive element at a depth of 10 nm is 3 times or more. 4. The lithium transition metal compound powder for a lithium secondary battery positive electrode material according to any one of items 1 to 3.   The additive contains a metal element (hereinafter referred to as “additive element”), and the additive element has a continuous composition gradient structure in which there exists a non-linear concentration gradient in the depth direction from the particle surface. The lithium transition metal-based compound powder for a lithium secondary battery positive electrode material according to any one of claims 1 to 4.   The median diameter measured after 5 minutes of ultrasonic dispersion (output 30 W, frequency 22.5 kHz) using a laser diffraction / scattering particle size distribution analyzer with a refractive index of 1.24 and a particle size standard as a volume standard. The lithium transition metal-based compound powder for a lithium secondary battery positive electrode material according to any one of claims 1 to 5, wherein the powder is 0.1 µm or more and less than 5 µm.   7. The lithium transition metal compound powder for a lithium secondary battery positive electrode material according to claim 1, wherein the average diameter of the primary particles is 0.1 μm or more and 0.9 μm or less. 8. The lithium transition metal compound powder for a lithium secondary battery positive electrode material according to claim 1, wherein the BET specific surface area is 1.5 m ² / g or more and 5 m ² / g or less. body. In mercury intrusion curve obtained by mercury intrusion porosimetry, mercury penetration amount at boosting the pressure 3.86kPa to 413MPa is, 0.7 cm ³ / g or more, claim 1, characterized in that 1.5 cm ³ / g or less The lithium transition metal type compound powder for lithium secondary battery positive electrode material of any one of thru | or 8.   Sub-peak in which pore distribution curve by mercury intrusion method has at least one main peak having a peak top at a pore radius of 300 nm or more and 1000 nm or less and a peak top at a pore radius of 80 nm or more and less than 300 nm The lithium transition metal-based compound powder for a lithium secondary battery positive electrode material according to any one of claims 1 to 9, wherein the powder is not contained. In the pore distribution curve by the mercury intrusion method, the pore volume relating to a peak having a peak top at a pore radius of 300 nm or more and 1000 nm or less is 0.4 cm ³ / g or more and 1 cm ³ / g or less. The lithium transition metal-based compound powder for a lithium secondary battery positive electrode material according to any one of claims 1 to 10. 12. The lithium transition metal compound for a lithium secondary battery positive electrode material according to claim 1, wherein the bulk density is 0.5 g / cm ³ or more and 1.7 g / cm ³ or less. powder. 13. The lithium according to claim 1, which has a volume resistivity of 1 × 10 ³ Ω · cm or more and 1 × 10 ⁶ Ω · cm or less when consolidated at a pressure of 40 MPa. Lithium transition metal compound powder for secondary battery positive electrode material.   14. The lithium secondary battery positive electrode material according to claim 1, comprising a lithium nickel manganese cobalt-based composite oxide including a crystal structure belonging to a layered structure as a main component. Lithium transition metal compound powder. The lithium transition metal compound powder for a lithium secondary battery positive electrode material according to claim 14, wherein the composition is represented by the following composition formula (I).
LiMO ₂ (I)
(However, in the above formula (I), M is an element composed of Li, Ni and Mn, or Li, Ni, Mn and Co. Mn / Ni molar ratio is 0.3 or more and 5 or less, (The Co / (Mn + Ni + Co) molar ratio is 0 or more and 0.30 or less, and the Li molar ratio in M is 0.001 or more and 0.2 or less.)   The lithium transition metal-based compound powder for a lithium secondary battery positive electrode material according to claim 14 or 15, which is fired at a firing temperature of 900 ° C or higher in an oxygen-containing gas atmosphere.   17. The lithium according to claim 14, wherein the C value is 0.005 wt% or more and 0.25 wt% or less when the carbon content is C (wt%). Lithium transition metal compound powder for secondary battery positive electrode material. The lithium transition metal compound for a lithium secondary battery positive electrode material according to any one of claims 15 to 17, wherein M in the composition formula (I) is represented by the following formula (II): powder.
M = Li _{z / (2 + z)} {(Ni _{(1 + y) / 2} Mn _{(1-y) / 2} ) _1-x Co _x } _{2 / (2 + z)} (II)
(However, in the above formula (II),
0 ≦ x ≦ 0.1
−0.1 ≦ y ≦ 0.1,
(1-x) (0.05-0.98y) ≤z≤ (1-x) (0.20-0.88y)
It is. )   In powder X-ray diffraction measurement using CuKα rays, 0.01 ≦ FWHM (110), where FWHM (110) is the half width of the (110) diffraction peak where the diffraction angle 2θ is around 64.5 °. The lithium transition metal-based compound powder for a lithium secondary battery positive electrode material according to claim 18, which is represented by ≦ 0.2. In powder X-ray diffraction measurement using CuKα rays, a diffraction angle 2θ is present at a diffraction peak near 64 ° (018), a (110) diffraction peak near 64.5 °, and around 68 ° ( 113) When the diffraction peak does not have a diffraction peak derived from a different phase or has a diffraction peak derived from a different phase on a higher angle side than each peak top, the integrated intensity ratio of the different phase peak to the diffraction peak of the original crystal phase The lithium transition metal-based compound powder for a lithium secondary battery positive electrode material according to claim 18 or 19, wherein each is in the following range.
0 ≦ I ₀₁₈ ^* / I ₀₁₈ ≦ 0.30
0 ≦ I ₁₁₀ ^* / I ₁₁₀ ≦ 0.25
0 ≦ I ₁₁₃ ^* / I ₁₁₃ ≦ 0.30
(Here, I ₀₁₈ , I ₁₁₀ , and I ₁₁₃ represent the integrated intensities of (018), (110), and (113) diffraction peaks, respectively, and I ₀₁₈ ^* , I ₁₁₀ ^* , and I ₁₁₃ ^* are (018 ), (110), (113) represents the integrated intensity of a diffraction peak derived from a different phase appearing at a higher angle than the peak top of the diffraction peak.)   In a liquid medium, a lithium compound, at least one transition metal compound selected from V, Cr, Mn, Fe, Co, Ni, and Cu, and an additive that suppresses grain growth and sintering during firing And a slurry preparation step for obtaining a slurry in which these are uniformly dispersed, a spray drying step for spray-drying the obtained slurry, and a firing step for firing the obtained spray-dried powder. The manufacturing method of the lithium transition metal type compound powder for lithium secondary battery positive electrode materials of any one of Claim 1 thru | or 20.   In the slurry preparation step, the lithium compound, the transition metal compound, and the additive are set in a liquid medium with a refractive index of 1.24 using a laser diffraction / scattering particle size distribution analyzer, and the particle size standard Is used as a volume reference and pulverized until the median diameter measured after ultrasonic dispersion for 5 minutes (output 30 W, frequency 22.5 kHz) is 0.4 μm or less. In the spray drying step, the slurry viscosity during spray drying is V ( cp) When the slurry supply amount is S (L / min) and the gas supply amount is G (L / min), spray drying is performed under the conditions of 50 cp ≦ V ≦ 4000 cp and 500 ≦ G / S ≦ 10000. The method for producing a lithium transition metal-based compound powder for a lithium secondary battery positive electrode material according to claim 21.   The transition metal compound includes at least a nickel compound, a manganese compound, and a cobalt compound, and in the firing step, the spray-dried powder is fired at 970 ° C. or higher in an oxygen-containing gas atmosphere. 22. The method for producing a lithium transition metal compound powder for a lithium secondary battery positive electrode material according to 22.   The method for producing a lithium transition metal-based compound powder for a lithium secondary battery positive electrode material according to any one of claims 21 to 23, wherein the lithium compound is lithium carbonate.   In a liquid medium, a lithium compound, at least one transition metal compound selected from V, Cr, Mn, Fe, Co, Ni, and Cu, and an additive that suppresses grain growth and sintering during firing A spray-dried product that is obtained by spray-drying a slurry in which these are uniformly dispersed and spray-dried, and is a precursor of a lithium transition metal compound powder for a positive electrode material for a lithium secondary battery, and is laser diffraction / scattering The median of the spray-dried body measured after ultrasonic dispersion (output 30 W, frequency 22.5 kHz) for 5 minutes with a refractive index set to 1.24 and a particle size reference as a volume reference by a particle size distribution analyzer A spray-dried product having a diameter of 0.01 μm or more and 4 μm or less. The spray-dried product according to claim 25, wherein the BET specific surface area is 10 m ² / g or more and 100 m ² / g or less.   21. A cathode active material layer containing the lithium transition metal compound powder for a lithium secondary battery cathode material according to any one of claims 1 to 20 and a binder on a current collector. A positive electrode for a lithium secondary battery.   28. A lithium secondary battery comprising a negative electrode capable of inserting and extracting lithium, a non-aqueous electrolyte containing a lithium salt, and a positive electrode capable of inserting and extracting lithium, wherein the lithium secondary battery according to claim 27 is used as the positive electrode. A lithium secondary battery using a positive electrode for a battery.

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