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    • 专利摘要:
    In the positive electrode active material for a lithium ion secondary battery mainly composed of Li-Mn-based composite oxide particles having a spinel structure, Porosity (%) = (A / B) × 100 The average value of the porosity of the particles represented by (A is the total cross-sectional area of the pores contained in the cross section of one secondary particle, B is the cross-sectional area of one secondary particle) is 15% or less, tap density is 1.9 g / ml or more, crystallite A positive electrode active material for lithium ion secondary batteries having a size of 400 to 960 Å and a lattice constant of 8.240 Å or less, a method for producing the positive electrode active material, and a lithium ion secondary battery using the positive electrode active material. The positive electrode active material according to the present invention has a dense particle shape and a spherical shape, has excellent chargeability to the electrode, and has a high initial capacity and capacity retention rate even in a high temperature environment as a secondary battery.
    公开号:KR20020012295A
    申请号:KR1020017016631
    申请日:2000-07-07
    公开日:2002-02-15
    发明作者:노다다카오；시라가와아키히코；가제죠셉；야마우치요시아키；오노후미요시
    申请人:오하시 미츠오；쇼와 덴코 가부시키가이샤；
    IPC主号:
    专利说明:

    Positive electrode active material, manufacturing method and secondary battery {POSITIVE PLATE ACTIVE MATERIAL, METHOD FOR PRODUCING THE SAME, AND SECONDARY CELL}
    [2] As a positive electrode active material for lithium ion secondary batteries, lithium manganese composite oxides (hereinafter referred to as Li-Mn-based composite oxides) having excellent safety and abundant resources have attracted attention.
    [3] However, Li-Mn-based composite oxides have a lower capacity per active material than lithium cobalt composite oxides (referred to as Li-Co-based composite oxides) and contain many voids in secondary particles. The active material mass mixed in the battery whose size is limited becomes small. As a result, there is a problem that the electric capacity per unit cell is small.
    [4] As an improvement, recently, a mixture of a manganese compound and a lithium compound is press-molded at a pressure of 500 kg / cm 2 or more, and then pulverized by heat treatment to obtain a tap density (appearance density of the powder obtained by vibrating the container under constant conditions). There is a proposal to obtain a Li-Mn composite oxide having a content of 1.7 g / ml or more (US Pat. No. 5805646, Japanese Patent Laid-Open No. 9 (1997) -86933).
    [5] However, the specific tap density disclosed was only 1.9 g / ml, which was not satisfactory.
    [6] The publication also discloses an average particle diameter of secondary particles in which primary particles of a Li-Mn composite oxide are agglomerated, but secondary particles may improve filler by utilizing interaction between primary particles. In the step of coating (electrode paste) the coating of the electrode material, the agglomeration is eliminated, and this is not an essential improvement.
    [7] Moreover, as a manufacturing method of the Li-Mn type | system | group composite oxide which has a spinel structure, the method of manufacturing by baking a mixture of a manganese oxide and a lithium compound at high temperature (for example, at 250 degreeC-850 degreeC) (Japanese Laid-Open Patent Publication) 9 (1997) -86933) or a Li-Mn-B-based oxide in which a manganese compound and a lithium compound are mixed with an oxide of boron element, which can be substituted with manganese, and calcined at high temperature to partially replace Mn with B. A method for producing a positive electrode active material of Japanese Patent Application Laid-Open No. 4 (1992) -237970 is disclosed.
    [8] However, when these raw materials are calcined at high temperature in the air or in an oxygen gas flow, the secondary particles after crushing have a large average porosity (15% or more) and low tap density (1.9 g / ml or less), so they are mixed in the electrode. The mass of the positive electrode active material is increased so that high capacity cannot be achieved.
    [9] Japanese Patent Laid-Open No. 4 (1992) -14752 discloses the use of a spinel-type lithium manganese oxide in which titanium oxide is mixed and sintered as a positive electrode active material, but titanium oxide is 950 ° C to 1000. If the temperature is not higher than or equal to 0 ° C, there is a problem that the tap density can be obtained only by 1.60 g / ml without reacting with lithium and manganese to produce a melt and adding 10% by mass of titanium oxide.
    [1] The present invention relates to a positive electrode active material for a lithium ion secondary battery, a manufacturing method thereof, and a lithium ion secondary battery using the positive electrode active material.
    [40] 1 is a scanning electron micrograph (* 15,000 times) of an example (Example 14) of the positive electrode active material granulated, baked, and sintered according to the present invention.
    [41] Fig. 2 is a particle size distribution diagram of an example (Example 14) of a positive electrode active material granulated, fired, and granulated according to the present invention.
    [10] (Initiation of invention)
    [11] An object of the present invention is to use a positive electrode active material for a lithium ion secondary battery having excellent chargeability, high initial capacity, and small capacity drop (high capacity retention) when repeated charging and discharging, a manufacturing method thereof, and a positive electrode active material The present invention provides a lithium ion secondary battery.
    [12] As a result of earnestly examining the present inventors, after disintegrating a fired product of a Li-Mn-based composite oxide having a spinel structure, the sintering accelerator is added to these pulverized particles, and granulated and fired. It succeeded in making densification of the solution solved the said subject.
    [13] That is, this invention provides the following positive electrode active material for lithium ion secondary batteries, its manufacturing method, the electrode paste containing this positive electrode active material, the positive electrode for lithium ion secondary batteries, and a lithium ion secondary battery.
    [14] [1] A positive electrode active material for lithium ion secondary batteries mainly comprising Li-Mn-based composite oxide particles having a spinel structure, wherein
    [15] Porosity (%) = (A / B) × 100
    [16] A positive electrode active material for a lithium ion secondary battery, characterized in that the average value of the porosity of the particles represented by (A is the total cross-sectional area of the pores contained in one cross-section of one secondary particle, and B is the cross-sectional area of one secondary particle) is 15% or less. .
    [17] [2] The positive electrode active material for lithium ion secondary batteries according to the above [1], wherein the average porosity is 10% or less, and the average particle diameter of the primary particles is 0.2 to 3 µm.
    [18] [3] The positive electrode active material for lithium ion secondary batteries according to the above [1], wherein the tap density of the positive electrode active material is 1.9 g / ml or more.
    [19] [4] The positive electrode active material for lithium ion secondary batteries described in [3], wherein the tap density of the positive electrode active material is 2.2 g / ml or more.
    [20] [5] The positive electrode active material for lithium ion secondary batteries according to the above [1], wherein the crystallite size of the positive electrode active material is 400 to 960 Hz.
    [21] [6] The positive electrode active material for lithium ion secondary batteries according to [1], wherein the lattice constant of the positive electrode active material is 8.240 GPa or less.
    [22] [7] A compound containing an element or an element whose positive electrode active material mainly consists of a Li-Mn-based composite oxide having a spinel structure, and whose oxide can be an oxide or an oxide that melts at a temperature of 550 ° C to 900 ° C, or Composed of an element or a compound containing an element or an element which may be an oxide or an oxide that is dissolved or reacted with lithium or manganese
    [23] The positive electrode active material for lithium ion secondary batteries as described in said [1] which is an granulated and sintered active material.
    [24] [8] An element or a compound containing an element, or a compound containing an element, or an oxide or oxide that melts at a temperature of 550 ° C to 900 ° C, or an oxide or oxide that is dissolved or reacted with lithium or manganese to melt. An element or a compound containing elements is a compound containing at least one element or element selected from the group consisting of Bi, B, W, Mo, and Pb, or a compound combining B 2 O 3 and LiF or MnF 2 and The positive electrode active material for lithium ion secondary batteries as described in said [7] which is a compound which combined LiF.
    [25] [9] A method for producing a positive electrode active material for a lithium ion secondary battery mainly composed of a Li-Mn-based composite oxide having a spinel structure, wherein the pulverized product of the Li-Mn-based composite oxide having a spinel structure is 550 ° C to 900 ° C. Adding an element or element containing an oxide or an oxide which melts at a temperature, or a compound containing an element or element which may be an oxide or oxide that melts or reacts with lithium or manganese to melt A method for producing a positive electrode active material for a lithium ion secondary battery, characterized by having a step of mixing and assembling.
    [26] [10] The method for producing a positive electrode active material for lithium ion secondary batteries according to [9], which has a step of sintering the granulated product in addition to the assembling step.
    [27] [11] In addition to the assembling process, the granulated product is heated at a rate of at least 100 ° C / min from a sinter shrinkage start temperature to at least 100 ° C or higher and held at that temperature for 1 minute to 10 minutes, and then The manufacturing method of the positive electrode active material for lithium ion secondary batteries as described in said [9] which has the process of temperature-falling and sintering to the sintering start temperature at the speed of 100 degree-C / min.
    [28] [12] The method for producing a positive electrode active material for lithium ion secondary batteries according to the above [11], which is sintered using a rotary kiln.
    [29] [13] The sintering step is a compound containing at least one element or element selected from the group consisting of Bi, B, W, Mo, and Pb on the surface of Li-Mn-based composite oxide particles, or B 2 O 3 and a lithium ion secondary battery production method of the positive electrode active material described in the above [10] is performed by sintering by melting a combination of compounds or a combination of LiF MnF 2 and LiF compound.
    [30] [14] The method for producing a positive electrode active material for lithium ion secondary batteries according to [9], wherein the average particle diameter of the pulverized product of the Li-Mn composite oxide having a spinel structure is 5 µm or less.
    [31] [15] The method for producing a positive electrode active material for lithium ion secondary batteries according to [9], wherein the average particle diameter of the pulverized product of the Li-Mn composite oxide having a spinel structure is 3 µm or less.
    [32] [16] The method for producing a positive electrode active material for a lithium ion secondary battery according to the above [9], wherein the granulation step is performed by a spray granulation method, a stirring granulation method, a compression granulation method, or a flow assembly method.
    [33] [17] In the granulation step, as a granulation aid, an acrylic resin, a copolymer of isobutylene and maleic anhydride, polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidene, hydroxypropyl cellulose Of the positive electrode active material for lithium ion secondary batteries according to the above [9], which uses at least one organic compound selected from the group consisting of loose, methyl cellulose, corn starch, gelatin, and lignin. Manufacturing method.
    [34] [18] The method for producing a positive electrode active material for lithium ion secondary batteries according to the above [17], which has a degreasing step in an atmosphere or a gas flow atmosphere containing oxygen at a temperature of 300 ° C to 550 ° C.
    [35] [19] A positive electrode active material for lithium ion secondary batteries obtained by the method according to any one of [9] to [18].
    [36] [20] An electrode paste containing the positive electrode active material for lithium ion secondary batteries according to any one of [1] to [8].
    [37] [21] A positive electrode for lithium ion secondary battery containing the positive electrode active material for lithium ion secondary battery according to any one of [1] to [8] or [19].
    [38] [22] A lithium ion secondary battery provided with the positive electrode for lithium ion secondary batteries described in [21] above.
    [39] [23] The lithium ion secondary battery according to the above [22], wherein the lithium ion secondary battery is a coin-type battery, a wound battery, a cylindrical, square battery, or a stacked battery.
    [42] Hereinafter, the present invention will be described in detail.
    [43] The present invention relates to a Li-Mn-based composite oxide positive electrode active material having a spinel structure in which the porosity of secondary particles is greatly reduced as compared with conventional products to 15% or less. Moreover, this invention relates to the Li-Mn type | system | group composite oxide which has a spinel structure whose average porosity of secondary particles is 10% or less, and its cycling characteristics are especially excellent compared with the conventional product.
    [44] That is, the positive electrode active material of the lithium-manganese (Li-Mn) -based composite oxide having a spinel structure according to the present invention is represented by the formula LiMn 2 O 4 , Li 1 + x Mn 2-x O 4 (wherein x is 0 <x <0.2). Or Mn is replaced by at least one element selected from the group consisting of chromium, cobalt, aluminum, nickel, iron, and magnesium (hereinafter referred to as M) in formula Li 1 + x Mn 2-x-y M The compound represented by y O 4 (wherein x is in the range of 0 <x <0.2 and y is 0 <y <0.4) is generically used.
    [45] In the present invention, the positive electrode active material for a lithium ion secondary battery is mainly composed of the Li-Mn-based composite oxide having the spinel structure, and the porosity of one secondary particle is represented by the following formula (1).
    [46] Porosity (%) = (A / B) × 100
    [47] (A is the total cross-sectional area of the pores contained in the cross section of one secondary particle, B is the cross-sectional area of one secondary particle), and an average porosity of 15% or less is used.
    [48] Moreover, as said Li-Mn type composite oxide, Preferably the average porosity of the said positive electrode active material is 10% or less, and the thing whose average particle diameter of a primary particle is 0.2-3 micrometers is used.
    [49] That is, in order for a tap density to exceed 1.9 g / ml as a positive electrode active material, it is necessary for the average porosity of secondary particles to be 15% or less. The average porosity of the secondary particles is preferably 13% or less, and more preferably 10% or less.
    [50] In general, in the method for producing a composite oxide, if the sintering shrinkage is increased by increasing the sintering temperature and the sintering time is increased, and the average porosity of the secondary particles is reduced as much as possible, the primary particles grow and grow as the sintering shrinkage increases. When used in a battery positive electrode active material, the capacity retention rate is lowered. As a result, battery characteristics after battery assembly deteriorate.
    [51] The present inventors have intensively studied the method of suppressing particle growth and sintering shrinkage, and as a result, at a rate of at least 100 ° C / min up to a temperature of at least 100 ° C higher than the sintering shrinkage initiation temperature measured by a thermo-mechanical analysis After the temperature was raised to 1 minute to 10 minutes, the temperature was lowered at a rate of at least 100 ° C./min to the sinter shrinkage start temperature, and it was found that sinter shrinkage can be suppressed by particle growth.
    [52] Here, the sinter shrinkage start temperature refers to the shrinkage start temperature obtained by the thermomechanical tester. As said holding temperature, it is necessary that it is a temperature at least 100 degreeC or more higher than a sintering shrinkage start temperature.
    [53] When the holding temperature is raised to less than 100 ° C. above the sintering start temperature, the sintering shrinkage rate is slow, so that the sintering time is long, and as a result, the grain grows and the primary particle diameter becomes larger than 0.5 μm.
    [54] In the sintering step, at a temperature of at least 100 ° C. or higher than the start temperature of the sintering shrinkage, the primary particle diameter is 0.2 μm or more and 0.5 μm or less, and the holding time for obtaining excellent battery characteristics is at least 1 minute to 10 minutes. .
    [55] If the holding time is less than 1 minute, the heat transfer time is too short, the primary particle diameter is less than 0.2 µm, the crystallization is insufficient, and the initial capacity is small. If the holding time exceeds 10 minutes, the particle growth proceeds even after sintering shrinkage, so that the primary particles become large and the capacity retention rate is lowered.
    [56] In the present invention, the holding time is preferably 2 minutes to 8 minutes, more preferably 2 minutes to 5 minutes.
    [57] In the temperature range from the sintering start temperature to the holding temperature, limiting the temperature increase rate and the temperature decrease rate to at least 100 ° C./min is to shorten the holding time in the temperature range where the particle growth proceeds as much as possible, thereby advancing only the sintering shrinkage and growing the particles. This is to suppress the.
    [58] Moreover, in order for the tap density of a positive electrode active material to exceed 2.2 g / ml, it is necessary for the average porosity of a secondary particle to be 10% or less, Preferably it is 7% or less, More preferably, it is 5% or less.
    [59] As for the crystallite size of the said positive electrode active material in this invention, 400-960 GPa is preferable. If the crystallite size is less than 400 GPa, the crystallinity is insufficient, so the initial capacity in the battery is low, and the capacity retention rate is low.
    [60] On the other hand, when the crystallite size exceeds 960 GPa, the capacity retention rate is severely reduced. Specifically, the preferred crystallite size is 500 to 920 GPa, more preferably 700 to 920 GPa.
    [61] Moreover, it is preferable that the lattice constant of the positive electrode active material of the Li-Mn type complex oxide which has the spinel structure of this invention is 8.240 GPa or less. When the lattice constant exceeds 8.240 GPa, the capacity retention rate of the battery becomes severe. Therefore, the preferable range of lattice constant is 8.235 GPa or less, More preferably, it is 8.233 GPa or less.
    [62] The positive electrode active material of the present invention mainly composed of a Li-Mn-based composite oxide having a spinel structure is obtained by pulverizing a fired product of a Li-Mn-based composite oxide having a spinel structure (this is a collection of primary particles). Dense granulated particles obtained by adding and mixing a sintering accelerator (assembly promoter) to the secondary particles, preferably having an average particle diameter of 0.5 µm or less, and granulated and calcined are used.
    [63] Here, the fine granulated particles mean that there are few or few voids between the primary particles of the oxide.
    [64] The positive electrode active material of the present invention is the dense granulated particles described above, and is formed using a sintering accelerator as described later.
    [65] Hereinafter, the manufacturing method of the positive electrode active material of this invention is demonstrated.
    [66] In the method for producing a Li-Mn composite oxide having a spinel structure, a mixture of a manganese compound and a lithium compound, or a mixture containing a compound containing a heterogeneous element which can be replaced with manganese is added to the atmosphere or oxygen gas. What is necessary is just to baked at least 1 hour at the temperature of 300-850 degreeC in a flow.
    [67] There is no restriction | limiting in particular about the crystallinity of the Li-Mn type complex oxide which has a spinel structure, Unreacted lithium compound and manganese oxide may remain.
    [68] In the case of using a Li-Mn-based composite oxide having a spinel structure with high crystallinity, the lattice constant is not particularly limited, but when used in a positive electrode active material having a lattice constant of 8.240 kPa or less, a decrease in capacity retention rate can be suppressed. .
    [69] The raw material of the Li-Mn-based composite oxide having a spinel structure is not particularly limited, but is preferably a known manganese compound such as manganese dioxide, manganese dioxide, manganese trioxide, or hydration. W) Manganese oxide, manganese carbonate, manganese nitrate and the like can be used, and lithium hydroxide, lithium carbonate, lithium nitrate and the like can be used.
    [70] More preferably, as the manganese compound, a lithium compound having excellent battery characteristics when adapted to the positive electrode active material and manganese carbonate which is easy to react at low temperatures are preferable.
    [71] In the preparation of the Li-Mn-M (hetero-element) -based composite oxide represented by manganese-substituted Li 1 + x Mn 2-x-y M y O 4 , chromium, cobalt, aluminum together with the raw materials of the manganese compound and the lithium compound , At least one element selected from the group consisting of nickel, iron and magnesium is used.
    [72] The compound containing the hetero element (M) may be any compound capable of forming the oxide by a heating reaction, and may be added together with a lithium compound or a manganese compound during the heating reaction.
    [73] There is no restriction | limiting in particular about the disintegration and grinding | pulverization method of the secondary particle of the Li-Mn type | system | group composite oxide which has the said spinel structure, A well-known crusher and grinder can be used. For example, a media stirring grinder, a ball mill, a paint shaker, a jet mill, a roller mill, etc. are mentioned.
    [74] The disintegration and grinding method may be dry or wet. There is no restriction | limiting in particular also about the solvent which can be used when wet, For example, water, alcohol, etc. are used.
    [75] From the viewpoint of promoting sinter shrinkage, the particle size of the Li-Mn composite oxide having a spinel structure after crushing and crushing is important.
    [76] It is preferable that the particle size is 5 micrometers or less in average particle diameter as measured with a laser particle size distribution analyzer. More preferably, it does not contain coarse grains of 5 micrometers or more, and an average particle diameter is 2 micrometers or less.
    [77] More preferably, the average particle diameter does not include coarse particles larger than 3 µm and is 1.5 µm or less, further 0.5 µm or less, more preferably 0.3 µm or less, and particularly preferably 0.2 µm or less.
    [78] The mixing method of the pulverized and pulverized Li-Mn composite oxide particles and the sintering accelerator is not particularly limited. For example, the above-described medium stirring grinder, ball mill, paint shaker, mixing mixer, etc. can be used. have.
    [79] The mixing method may be either dry or wet. When crushing and pulverizing a Li-Mn composite oxide, you may add and mix simultaneously with a sintering promoter.
    [80] The sintering accelerator may be any compound capable of sintering the disintegrated and pulverized particles of the Li-Mn-based composite oxide particles for granulation, more preferably a compound that melts at a temperature of 900 ° C. or lower, eg For example, the precursor may be an oxide or oxide that can be melted at a temperature of 550 ° C to 900 ° C, or a compound that may be an oxide or oxide that is dissolved in lithium or manganese, or reacts and melts. do.
    [81] As a sintering promoter, the compound containing elements, such as Bi, B, W, Mo, Pb, is mentioned, for example, You may use it combining these compounds arbitrarily.
    [82] Further compounds may be used a combination of B 2 O 3 and LiF compound or MnF 2 and a combination of LiF. Especially, the compound containing the elements of Bi, B, and W is preferable because a sintering shrinkage effect is large.
    [83] Examples of the Bi compound include bismuth trioxide, bismuth nitrate, bismuth benzoate, bismuth oxyacetate, bismuth oxycarbonate, bismuth citric acid, bismuth hydroxide and the like. Further, examples of the B compound include boron trioxide, boron carbide, boron nitride, boric acid, and the like. Tungsten dioxide, tungsten trioxide, etc. are mentioned as W compound.
    [84] The addition amount of the sintering promoter is preferably in the range of 0.0001 to 0.05 mol relative to 1 mol of Mn in the Li-Mn composite oxide in terms of the additive metal element. If the added amount in terms of the added metal element is less than 0.0001 mol, the sinter shrinkage effect is not obtained. If the added amount exceeds 0.05 mol, the initial capacity of the active material is reduced. Preferable addition amount is 0.005-0.03 mol.
    [85] The sintering accelerator may be used in a powder state or in a liquid state dissolved in a solvent. When it adds in a powder state, 50 micrometers or less are preferable, as for the average particle diameter of a sintering promoter, 10 micrometers or less are preferable, and 3 micrometers or less are further more preferable.
    [86] Although it is preferable to add a sintering promoter before granulation / sintering, you may sinter it by impregnating a granulated material at the temperature which can melt | dissolve the sintering accelerator after granulation.
    [87] The sintering accelerator is often left in the positive electrode material used for the battery after firing, and for example, it is detected by analysis that the sintering accelerator used in the production method of the present invention remains in the positive electrode active material.
    [88] Next, a granulation method will be described.
    [89] As the granulation method, a spray granulation method, a fluid granulation method, a compression granulation method, a stirring granulation method, etc. can be used using the said sintering promoter, and a medium flow drying, a medium vibration drying, etc. may be used together.
    [90] In this invention, what is necessary is just to be able to form a fine secondary particle (including granulated particle), and there is no restriction | limiting in particular in the formation method of granulation. Agitated granulation and compression granulation are particularly preferable because the density of secondary particles increases, and the spray granulation is a spherical shape of granulated particles.
    [91] Examples of the stirring granulator include a vertical granulator manufactured by Faurek Co., Ltd. and a Spartan Lyuzer Co., Ltd. manufactured by Bulda Powder Co., Ltd., as examples of the compression granulator. Note) A product, the roller compactor type MRCP-200, etc. As an example of a spray granulator, Ashimaza Niro Atomizer Co., Ltd. mobile type spray dryer etc. are mentioned.
    [92] There is no particular limitation on the size of the secondary particles to be assembled. When the average particle diameter of the granulated secondary particle becomes too large, it is good to set it as a desired particle size, for example, to disintegrate | pulverize and grind | pulverize and classify lightly immediately after granulation or after sintering. Generally, secondary particles having an average particle diameter of 10 to 20 µm are preferable.
    [93] In order to raise granulation efficiency, you may add an organic granulation aid. As such granulation aids, acrylic resins, copolymers of isobutylene and maleic anhydride, polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidene, hydroxypropyl cellulose, methyl cellulose, corn star Chia, gelatin, liglin and the like.
    [94] In the method of adding the granulation aid, it is more efficient to add the granulation aid by dissolving and spraying it in an organic solvent such as water or alcohol and spraying, rather than adding it in powder form.
    [95] As addition amount of a granulation aid, 5 mass parts or less are preferable with respect to 100 mass parts of Li-Mn type | system | group composite oxides having a spinel structure, and sintering accelerator, More preferably, it is 2 mass parts or less.
    [96] Next, the baking method of the granulated secondary particle is demonstrated.
    [97] The degreasing method of the granulated particles is carried out by holding at least 10 minutes in an air or a gas flow containing oxygen at a temperature range of 300 to 550 ° C. The carbon residue of the degreased granules is preferably 0.1% or less.
    [98] Firing of the granulated particles after degreasing is performed for 1 minute or more in the temperature range of 550 ° C to 900 ° C in the air or in a gas flow containing oxygen in order to suppress particle growth and to advance sintering shrinkage. The molten state can be maintained on the surface of the Mn-based composite oxide particles, thereby sintering shrinkage and densification of the secondary particles can be achieved.
    [99] In the present invention, the firing of the granulated particles after degreasing is at least than the sintering shrinkage start temperature measured by the thermomechanical tester in the air or in a gas flow containing oxygen in order to suppress grain growth and advance the sintering shrinkage. The temperature is raised to a high temperature of 100 ° C. at a rate of at least 100 ° C./min, and maintained for 1 minute to 10 minutes. Then, the temperature is lowered to a sinter shrinkage start temperature at a speed of at least 100 ° C./min to sinter shrinkage, and the secondary particles are densified. do. About the temperature increase rate and temperature-fall rate between normal temperature and sintered water start temperature, it may be 10 degrees C / min or less as before.
    [100] In addition, the sintering shrinkage of the particles of the granulated product which does not use the organic granulation aid described above, in the air, or in a gas flow atmosphere containing oxygen can be achieved to densify the secondary particles.
    [101] The positive electrode active material of the present invention and the positive electrode active material obtained by the production method of the present invention are processed into a positive electrode for a lithium ion secondary battery according to the same method as a conventional Li-Mn-based composite oxide and used for evaluation of a battery.
    [102] Hereinafter, the example which uses the said positive electrode active material of this invention as a positive electrode material of a nonaqueous secondary battery is demonstrated.
    [103] First, the positive electrode material is kneaded in a predetermined ratio with a solution (eg, N-methylpyrrolidone) in which the positive electrode active material, a conductivity-imparting agent such as carbon black or graphite, and a binder (binder) such as polyvinylidene fluoride are dissolved. And (iv) it is applied to an electrical power collector as an electrode paste, and then pressurized by a roll press or the like after drying. As a current collector, well-known metal current collectors, such as aluminum, stainless steel, and titanium, are used.
    [104] As the electrolyte salt in the electrolyte solution used in the nonaqueous secondary battery of the present invention, a known lithium salt containing fluorine can be used.
    [105] For example, LiPF 6 , LiPF 4 , LiN (CF 3 SO 2 ) 2 , LiAsF 6 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , or the like can be used. The electrolytic solution of a nonaqueous secondary battery is used by dissolving at least one electrolyte of a known lithium salt containing fluorine in a nonaqueous electrolytic solution.
    [106] As a non-aqueous solvent of the said non-aqueous electrolyte solution, the non-protonous thing which is chemically and electrochemically stable can be used.
    [107] For example, dimethyl carbonate, propylene carbonate, ethylene carbonate, methyl ethyl carbonate, methyl propyl carbonate, methyl lithium carbonate, methyl butyl carbonate, diethyl carbonate, ethyl propyl carbonate, diisopropyl carbonate, dibutyl carbonate, carbonate 1, 2 Carbonate esters, such as -butylene, ethyl isopropyl carbonate, and ethyl butyl carbonate, are mentioned.
    [108] In addition, oligoethers such as triethylene glycol methyl ether and tetraethylene glycol dimethyl ether, aliphatic esters such as methyl propionate and methyl formate, aromatic nitriles such as benzonitrile and trinitrile, amides such as dimethylformamide, and dimethyl Sulfoxides such as sulfoxide, lactones such as γ-butyrolactone, sulfur compounds such as sulfolane, N-vinylpyrrolidone, N-methylpyrrolidone, phosphate esters and the like. Especially, carbonate ester, aliphatic ester, and ether are preferable.
    [109] The negative electrode used in the nonaqueous secondary battery of the present invention is not particularly limited as long as it is a material capable of absorbing and discharging lithium ions. For example, lithium metal, lithium alloy, carbon material (including graphite), metal Carogen and the like can be used.
    [110] Next, an evaluation method of the electrode characteristics will be described.
    [111] As a positive electrode active material and a electrically conductive material, the Cabot's Balkan XC-72 and a binder ethylene tetrafluoride resin are mixed by the ratio of 50:34:16 by mass ratio, and this mixture is swollen with toluene for 12 hours.
    [112] The swollen mixture is applied onto a current collector made of aluminum x band metal, press-molded at 2 t / cm 2 , and toluene is dried to form a positive electrode. On the other hand, lithium foil is used as a negative electrode.
    [113] As the electrolytic solution is used that obtained by dissolving LiPF 6 in a mixed solution are mixed in a ratio of 1: 2 volume ratio of propylene carbonate and dimethyl carbonate in a 1 mol / liter concentration. As a separator, polypropylene is used, and silica fiber filter paper (for example, QR-100 which is Advantech Dongyang Co., Ltd.) is also used as a reinforcing material in order to prevent the micro short caused by the dendrite production | generation of a negative electrode.
    [114] Using these positive electrodes, negative electrodes, electrolytes, separators and reinforcing materials, 2016 type coin batteries were fabricated and subjected to 500 charge / discharge cycle tests in a thermostat set at 60 ° C.
    [115] The measurement conditions were constant current constant voltage charge-constant current discharge, charge and discharge rate 1C (charge stop for 2.5 hours at the start of charge), and scan voltage of 3.1V to 4.3V.
    [116] (The best mode for carrying out the invention)
    [117] Hereinafter, although an Example and a comparative example are given and this invention is demonstrated, this invention is not limited at all by the following description.
    [118] In addition, the characteristic of the following example and the positive electrode active material shown to Tables 1-3 was measured by the following method.
    [119] 1) Average particle diameter and specific surface area
    [120] Using a GRANULOMETER (HR 850 type) manufactured by CILAS as a laser particle size measuring instrument, the powder was dispersed with ultrasonic waves in a 0.2% aqueous solution of a surfactant (Model P manufactured by Huawang Co., Ltd.), and the particle size distribution was measured. Obtained.
    [121] 2) tap density
    [122] The measurement was carried out after tapping 2000 times with an amplitude of 8 mm using a tapping machine (KRS-409 type) manufactured by Jangji Scientific Instruments.
    [123] 3) porosity
    [124] By mixing and curing the positive electrode active material and the thermosetting resin, the positive electrode active material was embedded in the resin, cut into microtome, mirror polished, and the polished surface was photographed with a scanning electron microscope (SEM).
    [125] The cross-sectional area (B) of one secondary particle in the obtained SEM photographs and the total cross-sectional area (A) of all the pores included in the secondary particle cross-section are measured by an image analysis device, and the porosity of one secondary particle ( C) (%) was calculated and the average value of the porosity of 50 randomly selected secondary particles was made into the average porosity.
    [126] C (%) = (A / B) × 100
    [127] 4) determinant size
    [128] The X-ray diffraction peak of the (111) plane measured under the following conditions was calculated using Scherrer's equation.
    [129] In other words, assuming that the crystallite's appearance is a cube and does not have a distribution of size, the value obtained by calculating the diffraction line diffusion by the crystallite size at half width was used.
    [130] Further, after the single crystal silicon was pulverized with a tungsten carbide sample mill, a powder separated by sieving to 44 μm or less was used as an external standard, and an apparatus constant calibration curve was prepared.
    [131] Measuring Device and Method
    [132] The Rad type Goniometer, manufactured by Hakki Electric Co., Ltd., was used as the measurement mode for continuous measurement and analysis software. The RINT2000 series of Hakki Electric Co., Ltd. application software was used to analyze the crystallite size.
    [133] Measurement conditions are X-ray (CuK α-ray), output 50kV, 180mA, slit width (three locations): 1/2 °, 1/2 °, 0.15mm, 2θ / θ method for scanning method, 1 ° / min, the measuring range 2θ are 17 to 20 degrees, and the staff is 0.004 degrees. In addition, the precision of the crystallite size obtained by this method is ± 30 Hz.
    [134] 5) lattice constant
    [135] JBNelson, DPRiley's method (Proc. Phys. Soc., 57 , 160 (1945)).
    [136] 6) Specific surface area
    [137] It measured by BET method.
    [138] 7) Shape of granulated particles
    [139] Photograph the assembly of the positive electrode active material by SEM and analyze the image to find the circularity (circularity = 4π [area / (peripheral length) 2 )) and needle ratio (needle ratio = maximum absolute length / diagonal width) of secondary particles. For each sample, 200 secondary particles were measured for each sample, and their average value was obtained.
    [140] Example 1
    [141] So that a composition of Li / Mn atomic ratio of 0.51, specific surface meonjeok 22m was mixed with a manganese carbonate (Central Electric Industry Co., Ltd. products, C2-10) and lithium carbonate (bonap Chemical Co. product 3N) ball mill for 2 / g, The Li / Mn composite oxide was synthesized by raising the temperature from room temperature to 650 ° C. at a heating rate of 200 ° C./hr in the air atmosphere and maintaining the temperature for 4 hours.
    [142] In the composite, extremely small amounts of 32 manganese oxides in addition to the Li-Mn-based composite oxide were detected by the X-ray analyzer (XRD).
    [143] The average particle diameter of the composite product measured by the laser particle size distribution analyzer was 10 µm, and the specific surface area was 7.7 m 2 / g.
    [144] The obtained Li-Mn composite oxide having a spinel structure was dispersed in an ethanol solvent and pulverized with a wet ball mill to have an average particle diameter of 0.5 탆. As a result of the measurement, the pulverized powder did not contain large particles of 3 µm or more, and the specific surface area was 27.8 m 2 / g. Bismuth oxide with an average particle diameter of 2 µm was added to and mixed with the pulverized powder so that the atomic ratio of Bi / Mn was 0.0026. Assembled.
    [145] 1.5 parts by mass of polyvinyl alcohol was dissolved in an aqueous solution and added to 100 parts by mass of a mixed powder of a Li-Mn composite oxide and bismuth oxide, and granulated for 16 minutes. The obtained granulated material was lightly pulverized and pulverized by a mixer, and was sized to an average particle diameter of 15 mu m using a wind classifier. The tap density of the granulated material after sizing was 1.65 g / ml.
    [146] The obtained granulated material was held at 500 ° C in air for 2 hours, degreased (polyvinyl alcohol was decomposed), and then heated to 200 ° C / hr in air and held at 750 ° C for 20 hours to obtain a positive electrode active material.
    [147] The positive electrode active material produced here was found to contain a significant amount of the composition ratio of mixing Bi elements of the bismuth oxide by the ICP-AES method (inductively coupled plasma emission spectrometry).
    [148] The average porosity of the obtained positive electrode active material was 11.2%. The tap density of the positive electrode active material was 1.96 g / ml, the crystallite size was 880 GPa, and the lattice constant was 8.233 GPa.
    [149] The coin-type battery was produced as follows using the said positive electrode active material. Polyvinylidene fluoride dissolved in N-methyl-2-pyrrolidone as a positive electrode active material, carbon black as a conductive material, was kneaded at a ratio of 80:10 to 10 by mass ratio, coated on aluminum foil, and pressed to obtain a positive electrode.
    [150] As the negative electrode, a lithium foil having a predetermined thickness was used. As an electrolyte solution, a carbonate pro tolylene and dimethyl carbonate in a volume ratio was used that obtained by dissolving LiPF 6 in a mixed solution are mixed in a ratio of 2 to 1 mol / liter concentration. Using these positive electrodes, negative electrodes, polypropylene separators, electrolyte solutions and glass filters, a 2016 type coin cell was produced.
    [151] The charge and discharge cycle test at 60 ° C. of the battery produced by the above method was repeated for 100 cycles of charge and discharge under conditions of charge / discharge rate 1C (charge stop at 2.5 hours from the start of charge) and a voltage range of 3.0 to 4.2V. The initial discharge capacity and the capacity retention rate (%) after 100 cycles are shown in Table 1 together with other measurement results.
    [152] Example 2
    [153] The porosity, tap density, crystallite size, lattice constant, and electrode characteristics of the secondary particles were evaluated in the same manner as in Example 1 except that the manganese raw material in the Li-Mn composite oxide synthesis condition was electrolytic manganese dioxide. The results are shown in Table 1.
    [154] Example 3
    [155] Manganese carbonate, lithium carbonate and aluminum hydroxide are mixed by a ball mill so that the atomic ratio of Li / Mn / Al is 1.02: 1.967: 0.013, and the temperature is raised from room temperature to 650 ° C. at a heating rate of 200 ° C./hr in an air atmosphere. It hold | maintained at 4 degreeC for 4 hours, and synthesize | combined Li-Mn type | system | group composite oxide.
    [156] In the composite, trace amounts of 32 manganese oxides in addition to Li-Mn-based composite oxides were detected by XRD. The average particle diameter of the composite, measured by a laser particle size analyzer, was 10 μm.
    [157] The obtained Li-Mn composite oxide was ground to an average particle diameter of 0.5 mu m, and boron oxide was added and granulated so that the atomic ratio of B / Mn was 0.0208.
    [158] Next, it carried out similarly to Example 1 except having baked the granulated material after degreasing at 750 degreeC for 0.5 hr. The results are shown in Table 1.
    [159] Example 4
    [160] It carried out similarly to Example 3 except having set the atomic ratio of B / Mn to 0.009, and baking the degreased granulated substance at 760 degreeC for 0.5 hr. The results are shown in Table 1.
    [161] Example 5
    [162] It carried out similarly to Example 3 except having set the atomic ratio of B / Mn to 0.006, and baking the degreased granulated product at 770 degreeC for 0.5 hr. The results are shown in Table 1.
    [163] Example 6
    [164] It carried out similarly to Example 1 except having baked the granulated material after degreasing at 760 degreeC for 20 hours. The results are shown in Table 1.
    [165] Example 7
    [166] The same procedure as in Example 1 was carried out except that bismuth oxide was changed to tungsten trioxide, and the tungsten trioxide was added at an atomic ratio of W / Mn of 0.0208, and the granulated product after degreasing was baked at 750 ° C for 20 hours. It was carried out. The results are shown in Table 1.
    [167] Example 8
    [168] The Li-Mn composite oxide synthesized in Example 1 was further crystallized by raising the atmospheric heating rate from room temperature to 750 ° C. at 200 ° C./hr and holding at 750 ° C. for 20 hours. Thereafter, the Li-Mn composite oxide crystallized in Example 1 was used, the bismuth oxide was changed to boron oxide, and the boron oxide was added at a ratio of B / Mn of 0.0208, and the granulated product after degreasing. It carried out similarly to Example 1 except having baked at 0.5 hours at 750 degreeC. The results are shown in Table 1.
    [169] Example 9
    [170] It carried out similarly to Example 3 except having used the average particle diameter of 3.5 micrometers, and the specific surface area as 10-m <2> / g as Li-Mn type | system | group composite oxide before granulation. The results are shown in Table 1.
    [171] Example 10
    [172] Except for using the Li-Mn composite oxide synthesized by mixing a manganese carbonate, lithium carbonate and aluminum hydroxide in a ball mill so that the atomic ratio of Li / Mn / Al to a composition of 1.03: 1.967: 0.013 Was carried out. The results are shown in Table 1.
    [173]
    [174] Example 11
    [175] It carried out similarly to Example 1 except having baked the granulated material after degreasing at 830 degreeC for 20 hours. The results are shown in Table 2.
    [176] Example 12
    [177] In the same manner as in Example 3, except that a Li-Mn-based composite oxide synthesized by mixing a manganese carbonate, lithium carbonate and aluminum hydroxide in a ball mill so that the atomic ratio of Li / Mn / Al is 0.99: 1.967: 0.013 is used. Was carried out. The results are shown in Table 2.
    [178] Example 13
    [179] It carried out similarly to Example 3 except having set the average particle diameter after granulation to 65 micrometers. The results are shown in Table 2.
    [180] Example 14
    [181] It carried out similarly to Example 1 except having made the atomic ratio of Bi / Mn into the ratio of 0.0020. The results are shown in Table 2.
    [182] As a result of observing the granulated, calcined, and established positive electrode active material obtained by the scanning electron microscope (x15,000 times), it was found that the particles were round particles as shown in FIG. The particle size distribution of this particle is shown in Table 2.
    [183] Comparative Example 1
    [184] It carried out similarly to Example 1 except having set the average particle diameter of the Li-Mn type complex oxide before granulation to 6.0 micrometers. The results are shown in Table 2.
    [185] Comparative Example 2
    [186] With an atomic ratio of Li / Mn of 0.51, the electrolytic manganese dioxide and lithium carbonate having an average particle diameter of 20 µm were mixed by a ball mill, and the temperature was raised to 760 ° C at a heating rate of 100 ° C / hr in the air and maintained at 760 ° C for 24 hours. The positive electrode active material was synthesized. The positive electrode active material thus obtained was evaluated in the same manner as in Example 1. The results are shown in Table 2.
    [187] Comparative Example 3
    [188] It carried out similarly to Example 1 except having assembled without adding a sintering accelerator. The results are shown in Table 2.
    [189] Comparative Example 4
    [190] It carried out similarly to Example 3 except having baked the granulated material at 750 degreeC for 20 hours. The results are shown in Table 2.
    [191]
    [192] Example 15
    [193] Manganese carbonate, lithium carbonate and aluminum hydroxide are mixed by a ball mill so that the atomic ratio of Li / Mn / Al is 1.02: 1.967: 0.013, and the temperature is raised from room temperature to 650 ° C. at a heating rate of 200 ° C./hr in an air atmosphere. The mixture was kept at 4 ° C. for 4 hours to synthesize a Li / Mn composite oxide.
    [194] In the composite, trace amounts of 32 manganese oxides in addition to Li-Mn based composite oxides were detected in XRD. The average particle diameter of the composite, measured by a laser particle size analyzer, was 10 μm.
    [195] Boron oxide was added to the obtained Li-Mn composite oxide so that the atomic ratio of B / Mn was 0.0208, it was disperse | distributed to the ethanol solvent, it grind | pulverized by the wet ball mill, and the average particle diameter was 0.3 micrometer.
    [196] The obtained pulverized product was stirred and granulated with Spartan Ryuzer RMO-6H manufactured by Buley Powder Co., Ltd.
    [197] 1.5 mass parts of polyvinyl alcohol of a granulation aid was melt | dissolved in aqueous solution, and it granulated for 16 minutes with respect to 100 mass parts of Li-Mn type | system | group composite oxides and boron oxide.
    [198] The obtained granulated material was lightly pulverized and pulverized by a mixer, and was sized to an average particle diameter of 15 mu m using a wind classifier. The tap density of the granulated material after sizing was 1.60 g / ml.
    [199] The obtained granulated material was kept at 500 ° C. for 2 hours in air to degrease (decompose polyvinyl alcohol).
    [200] It was 660 degreeC when the sintering shrinkage start temperature of the degreasing granulated powder was measured with the thermomechanical tester.
    [201] Next, the degreased granulated powder was sintered using a rotary kiln under the following conditions.
    [202] The temperature of the cracking zone of the rotary kiln was 780 ° C, and the feed rate of the granulated powder, the rotation speed and the slope of the rotary kiln were set such that the degreased granulated powder passed through the cracking zone in 3 minutes.
    [203] The time required for the granulated powder to enter the cracking zone at the inlet and the exit of the rotary kiln after exiting the cracking zone was 6.3 minutes.
    [204] The average porosity of the obtained positive electrode active material was 2.1%. Moreover, when the longest diameter of 500 primary particles was measured in the SEM photograph, the average particle diameter was 0.40 micrometer.
    [205] Using the positive electrode active material described above, a coin-type battery was manufactured in the same manner as in Example 1.
    [206] The charge and discharge cycle test at 60 ° C. of the battery produced by the above method was repeated for 100 cycles of charge and discharge under conditions of charge and discharge rate (1C) and a voltage range of 3.0 to 4.2 V.
    [207] Table 3 shows the initial discharge capacity and the capacity retention rate (%) after 100 cycles.
    [208] Example 16
    [209] Example 15 The temperature of the cracking zone of the rotary kiln was set to 780 ° C., except that the feed speed of the granulated powder, the rotational speed and the slope of the rotary kiln were set so that the degreased granulated powder passed the cracking zone in 9 minutes. Was carried out in the same manner. The results are shown in Table 3.
    [210] Example 17
    [211] Manganese carbonate, lithium carbonate and vapor phase alumina are mixed so that the atomic ratio of Li / Mn / Al is 1.02: 1.967: 0.013, and the temperature is raised from room temperature to 650 ° C at a heating rate of 200 ° C / hr in an air atmosphere, at 650 ° C. It was kept for 4 hours to synthesize a Li / Mn based composite oxide.
    [212] In the composite, trace amounts of 32 manganese oxides in addition to Li-Mn based composite oxides were detected in XRD. The average particle diameter of the composite, measured by a laser particle size analyzer, was 10 μm.
    [213] Boron oxide was added to the obtained Li-Mn composite oxide so as to have an atomic ratio of B / Mn of 0.0104, dispersed in ion-exchanged water, and pulverized with a medium stirring fine grinding machine to obtain an average particle diameter of 0.18 탆.
    [214] 1.5 mass% of granulation aids (Isoban 104, Kraray Co., Ltd. product) were added to the obtained crushed slurry, and dry granulation was carried out with a disk rotary spray dryer. The granulated material was spherical particles having an average particle diameter of 18.3 µm, and the tap density was 1.54 g / ml.
    [215] The granulated material thus obtained was kept at 500 ° C in air for 2 hours, and then degreased, followed by sintering under the same conditions as in Example 15 using a rotary kiln.
    [216] The average porosity of the obtained positive electrode active material was 1.7%, the average particle diameter was 0.27 µm, the tap density was 2.40 g / ml, and the specific surface area measured by the BET method was 0.8 m 2 / g. Table 3 shows the characteristics of the coin-type battery produced in the same manner as in Example 15 using this positive electrode active material.
    [217] Example 18
    [218] It carried out similarly to Example 15 except having set the temperature of the cracking zone of a rotary kiln to 850 degreeC. The results are shown in Table 3.
    [219] Example 19
    [220] It carried out similarly to Example 17 except having set the temperature of the cracking zone of a rotary kiln to 850 degreeC. The results are shown in Table 3.
    [221] Comparative Example 5
    [222] The granulated material after degreasing was heated at a rate of 10 ° C./min at 650 ° C., held at 0.5 ° C. at 750 ° C. for sintering, and then lowered at a rate of 10 ° C./min to 650 ° C. in the same manner as in Example 15. Was carried out. In addition, the obtained positive electrode active material was evaluated in the same manner as in Example 15. The results are shown in Table 3.
    [223] Comparative Example 6
    [224] It carried out similarly to the comparative example 5 except having hold | maintained and sintered at 750 degreeC for 20 hours. The results are shown in Table 3.
    [225] Comparative Example 7
    [226] The temperature of the cracking zone of the rotary kiln was set at 780 ° C, and the feed speed of the granulated powder, the rotational speed and the slope of the rotary kiln were set so that the degreased granulated powder passed the cracking zone at 0.5 minutes, and the granulated powder was placed at the inlet. The time required to enter the cracking zone and the time required to exit the rotary kiln after exiting the cracking zone were the same as in Example 15 except that all were 1.5 minutes. The results are shown in Table 3.
    [227]
    [228] Analysis of Shape Measurement Results of Assembled Particles
    [229] The circularity (circularity = 4π [area / (peripheral length) 2 )) and needle ratio (needle ratio = needle maximum) of secondary particles prepared in Examples 1 to 19 and Comparative Examples 1 to 7 shown in Tables 1 to 3 From the measurement result of length / diagonal width, it turned out that the positive electrode active material manufactured in the Example has a circularity of 0.7 or more and needle shape ratio of 1.35 or less.
    [230] The positive electrode active material of the present invention is essentially different in terms of granulation and sintering as compared with secondary particles using conventionally known cohesive force, and the particles are denser than the positive electrode active material obtained by the conventional method. In addition, it is spherical, has excellent chargeability to the electrode, and exhibits an effect of increasing initial capacity and capacity retention rate even in a high temperature environment as a secondary battery.
    [231] According to the method for producing a positive electrode active material of the present invention, by adding a sintering accelerator which forms a melt in a high temperature region to a Li-Mn-based composite oxide, densification of secondary particles is achieved, and in the conventional method, initial capacity and cycle characteristics Even when grown to such deteriorated crystallite size, excellent battery performance is obtained.
    [232] The problem of deterioration of initial capacity and cycle characteristics in which the primary particle size grows larger than 0.5 μm when the secondary particles are densified in the conventional method is that the sintering accelerator which forms a melt in the high temperature region is applied to the Li-Mn composite oxide. It is solved by the method of this invention to add, and the positive electrode active material which has high chargeability and excellent battery performance is obtained.
    [233] Since the lithium ion secondary battery of this invention uses the positive electrode active material excellent in chargeability, it is excellent in the initial stage capacity and capacity | capacitance retention at high temperature.
    权利要求:
    Claims (23)
    [1" claim-type="Currently amended] In the positive electrode active material for a lithium ion secondary battery mainly composed of Li-Mn-based composite oxide particles having a spinel structure,
    Porosity (%) = (A / B) × 100 (1)
    A positive electrode active material for a lithium ion secondary battery, characterized in that the average value of the porosity of the particles represented by (A is the total cross-sectional area of the pores contained in one cross-section of one secondary particle, and B is the cross-sectional area of one secondary particle) is 15% or less. .
    [2" claim-type="Currently amended] The positive electrode active material for lithium ion secondary batteries according to claim 1, wherein the average porosity is 10% or less, and the average particle diameter of the primary particles is 0.2 to 3 m.
    [3" claim-type="Currently amended] The positive electrode active material for lithium ion secondary batteries according to claim 1, wherein the tap density of the positive electrode active material is 1.9 g / ml or more.
    [4" claim-type="Currently amended] The positive electrode active material for lithium ion secondary batteries according to claim 3, wherein the tap density of the positive electrode active material is 2.2 g / ml or more.
    [5" claim-type="Currently amended] The cathode active material for lithium ion secondary batteries according to claim 1, wherein the crystallite size of the cathode active material is 400 to 960 kPa.
    [6" claim-type="Currently amended] The positive electrode active material for lithium ion secondary batteries according to claim 1, wherein the lattice constant of the positive electrode active material is 8.240 GPa or less.
    [7" claim-type="Currently amended] The positive electrode active material mainly comprises a Li-Mn-based composite oxide having a spinel structure, and the oxide contains an element or an element which can be an oxide or an oxide that melts at a temperature of 550 ° C to 900 ° C. A compound or an element or a compound containing an element which can be an oxide or an oxide which is dissolved or reacted with lithium or manganese and melts, and is an active material which is granulated and sintered. Positive electrode active material for lithium ion secondary battery.
    [8" claim-type="Currently amended] 8. The method according to claim 7, wherein the element or element containing the element may be an oxide or an oxide that melts at a temperature of 550 ° C to 900 ° C, or an oxide or oxide that melts or reacts with or melts with lithium or manganese. A compound containing at least one element or element selected from the group consisting of Bi, B, W, Mo, and Pb, or a compound combining B 2 O 3 and LiF A cathode active material for a lithium ion secondary battery, characterized in that the compound combines MnF 2 and LiF.
    [9" claim-type="Currently amended] In the method for producing a positive electrode active material for a lithium ion secondary battery mainly composed of a Li-Mn-based composite oxide having a spinel structure, it is melted at a temperature of 550 ° C to 900 ° C in a pulverized product of a Li-Mn-based composite oxide having a spinel structure. Assemble by adding and mixing an element or an element obtained by an oxide or an oxide, or an element or an element containing an element or an element which can be dissolved or reacted with lithium or manganese or melted and reacted to melt A method for producing a positive electrode active material for a lithium ion secondary battery, comprising the step of (iii).
    [10" claim-type="Currently amended] The method of manufacturing a positive electrode active material for a lithium ion secondary battery according to claim 9, further comprising a step of sintering the granulated material in addition to the granulation step.
    [11" claim-type="Currently amended] The method of claim 9, wherein, in addition to the granulation step, the granulated product is heated at a rate of at least 100 ° C / min from a sinter shrinkage start temperature to at least 100 ° C or higher and held at that temperature for 1 minute to 10 minutes. And a step of lowering and sintering to a sintering start temperature at a rate of at least 100 ° C./min, the method for producing a positive electrode active material for lithium ion secondary batteries.
    [12" claim-type="Currently amended] The method for producing a positive electrode active material for lithium ion secondary batteries according to claim 11, wherein the rotary kiln is sintered.
    [13" claim-type="Currently amended] The compound according to claim 10, wherein the sintering step contains at least one element or element selected from the group consisting of Bi, B, W, Mo, and Pb on the surface of the Li-Mn-based composite oxide particle, or B 2 A method for producing a positive electrode active material for a lithium ion secondary battery, characterized by melting and sintering a compound combining O 3 and LiF or a compound combining MnF 2 and LiF.
    [14" claim-type="Currently amended] The manufacturing method of the positive electrode active material for lithium ion secondary batteries of Claim 9 whose average particle diameter of the pulverized thing of the Li-Mn type | system | group composite oxide which has a spinel structure is 5 micrometers or less.
    [15" claim-type="Currently amended] The manufacturing method of the positive electrode active material for lithium ion secondary batteries of Claim 9 whose average particle diameter of the grinding | pulverization thing of the Li-Mn type complex oxide which has a spinel structure is 3 micrometers or less.
    [16" claim-type="Currently amended] The method of manufacturing a positive electrode active material for a lithium ion secondary battery according to claim 9, wherein the granulation step is performed by a spray granulation method, a stirring granulation method, a compression granulation method, or a flow assembly method.
    [17" claim-type="Currently amended] 10. The granulation aid according to claim 9, wherein in the granulation step, an acrylic resin, a copolymer of isobutylene and maleic anhydride, polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidene, and hydride are used as granulation aids. A method for producing a positive electrode active material for a lithium ion secondary battery, characterized by using at least one organic compound selected from the group consisting of oxypropyl cellulose, methyl cellulose, corn starch, gelatin, and lignin.
    [18" claim-type="Currently amended] 18. The method for producing a cathode active material for a lithium ion secondary battery according to claim 17, further comprising a degreasing step at a temperature of 300 ° C to 550 ° C in an atmosphere or a gas flow atmosphere containing oxygen.
    [19" claim-type="Currently amended] The positive electrode active material for lithium ion secondary batteries obtained by the method as described in any one of Claims 9-18.
    [20" claim-type="Currently amended] The electrode paste containing the positive electrode active material for lithium ion secondary batteries in any one of Claims 1-8.
    [21" claim-type="Currently amended] The positive electrode for lithium ion secondary batteries containing the positive electrode active material for lithium ion secondary batteries in any one of Claims 1-8.
    [22" claim-type="Currently amended] The lithium ion secondary battery provided with the positive electrode for lithium ion secondary batteries of Claim 21.
    [23" claim-type="Currently amended] The lithium ion secondary battery according to claim 22, wherein the lithium ion secondary battery is a coin-type battery, a wound battery, a cylindrical, a square battery or a stacked battery.
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    同族专利:
    公开号 | 公开日
    JP2011049180A|2011-03-10|
    AU5850200A|2001-01-30|
    CN1179437C|2004-12-08|
    JP5464717B2|2014-04-09|
    KR100653170B1|2006-12-04|
    JP2012074390A|2012-04-12|
    CN1360739A|2002-07-24|
    WO2001004975A1|2001-01-18|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1999-07-07|Priority to JP19331499
    1999-07-07|Priority to JPJP-P-1999-00193314
    2000-04-26|Priority to JPJP-P-2000-00126494
    2000-04-26|Priority to JP2000126494
    2000-07-07|Application filed by 오하시 미츠오, 쇼와 덴코 가부시키가이샤
    2002-02-15|Publication of KR20020012295A
    2006-12-04|Application granted
    2006-12-04|Publication of KR100653170B1
    优先权:
    申请号 | 申请日 | 专利标题
    JP19331499|1999-07-07|
    JPJP-P-1999-00193314|1999-07-07|
    JPJP-P-2000-00126494|2000-04-26|
    JP2000126494|2000-04-26|
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