WO2012128289A1 - Positive electrode active material for lithium-ion battery, positive electrode for lithium-ion battery, and lithium-ion battery - Google Patents
Positive electrode active material for lithium-ion battery, positive electrode for lithium-ion battery, and lithium-ion battery Download PDFInfo
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- WO2012128289A1 WO2012128289A1 PCT/JP2012/057209 JP2012057209W WO2012128289A1 WO 2012128289 A1 WO2012128289 A1 WO 2012128289A1 JP 2012057209 W JP2012057209 W JP 2012057209W WO 2012128289 A1 WO2012128289 A1 WO 2012128289A1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
- H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
- H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Definitions
- the present invention relates to a positive electrode active material for a lithium ion battery, a positive electrode for a lithium ion battery, and a lithium ion battery.
- Lithium-containing transition metal oxides are generally used as positive electrode active materials for lithium ion batteries. Specifically, lithium cobaltate (LiCoO 2 ), lithium nickelate (LiNiO 2 ), lithium manganate (LiMn 2 O 4 ), etc., improved characteristics (higher capacity, cycle characteristics, storage characteristics, reduced internal resistance) In order to improve the rate characteristics and safety, it is underway to combine them. Lithium ion batteries for large-scale applications such as in-vehicle use and load leveling are required to have different characteristics from those of conventional mobile phones and personal computers.
- Patent Document 1 discloses: Li x Ni 1- y My O 2- ⁇ (0.8 ⁇ x ⁇ 1.3, 0 ⁇ y ⁇ 0.5, and M is Co, Mn, Fe, Cr, V, Ti, Cu, Al, Ga, Bi, Sn, Zn, Mg, It represents at least one element selected from the group consisting of Ge, Nb, Ta, Be, B, Ca, Sc and Zr, ⁇ corresponds to oxygen deficiency or oxygen excess, ⁇ 0.1 ⁇ ⁇ 0.1
- a method for producing a positive electrode material for a lithium secondary battery characterized in that small substances are blended at a weight ratio of 0: 100 to 100: 0. And according to this, it is described that the positive electrode material for lithium secondary batteries with various balance of rate characteristics and capacity can be easily manufactured.
- Patent Document 1 Although the lithium nickel composite oxide described in Patent Document 1 has an excessive amount of oxygen in its composition formula, there is still room for improvement as a high-quality positive electrode active material for lithium ion batteries.
- an object of the present invention is to provide a positive electrode active material for a lithium ion battery having good battery characteristics.
- the present inventor has found that there is a close correlation between the amount of oxygen of the positive electrode active material, the particle size of the primary particles, and the battery characteristics. That is, it has been found that good battery characteristics can be obtained by setting the positive electrode active material oxygen amount to a certain value or more and controlling the primary particle size of the positive electrode active material within an appropriate range. Further, the present inventors have found that there is a close correlation between the carbon content of the positive electrode active material and the amount of lithium carbonate that is residual alkali on the particle surface of the positive electrode active material, and the battery characteristics. That is, it has been found that particularly good battery characteristics can be obtained when the carbon content of the positive electrode active material is below a certain value or when the amount of lithium carbonate on the particle surface of the positive electrode active material is below a certain value.
- Composition formula Li (Li x Ni 1- xy M y) O 2 + ⁇
- M is at least one selected from Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Ga, Ge, Bi, Sn, Mg, Ca, B and Zr; (0 ⁇ x ⁇ 0.1, 0 ⁇ y ⁇ 0.7, and ⁇ > 0)
- the particle size of the primary particles is 1.6 to 2.3 ⁇ m
- the carbon amount measured by the LECO method is 0.40% by mass or less
- the positive electrode active material for a lithium ion battery according to the present invention has a carbon content of 0.20% by mass or less as measured by LECO method, and is a carbonic acid that is residual alkali on the particle surface as measured by neutralization titration.
- the amount of lithium is 0.60 mass% or less.
- the positive electrode active material for a lithium ion battery according to the present invention is at least one selected from Mn and Co.
- the positive electrode active material for a lithium ion battery according to the present invention has ⁇ > 0.05 in the composition formula.
- the positive electrode active material for a lithium ion battery according to the present invention has ⁇ > 0.1 in the composition formula.
- the present invention is a positive electrode for a lithium ion battery using the positive electrode active material for a lithium ion battery according to the present invention.
- the present invention is a lithium ion battery using the positive electrode for a lithium ion battery according to the present invention.
- a positive electrode active material for a lithium ion battery having good battery characteristics can be provided.
- FIG. 1 is an appearance photograph of primary particles and secondary particles of a positive electrode active material.
- lithium cobaltate LiCoO 2
- lithium-containing transition metal oxides such as lithium nickelate (LiNiO 2 ) and lithium manganate (LiMn 2 O 4 ).
- the positive electrode active material for a lithium ion battery of the present invention produced using such a material is Composition formula: Li (Li x Ni 1- xy M y) O 2 + ⁇
- M is at least one selected from Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Ga, Ge, Bi, Sn, Mg, Ca, B and Zr; (0 ⁇ x ⁇ 0.1, 0 ⁇ y ⁇ 0.7, and ⁇ > 0) It is represented by
- oxygen is expressed as O 2 + ⁇ ( ⁇ > 0) as described above in the composition formula, and is excessively contained. Battery characteristics such as rate characteristics and capacity retention are improved.
- ⁇ is preferably ⁇ > 0.05, and more preferably ⁇ > 0.1.
- the positive electrode active material for lithium ion batteries is composed of primary particles, secondary particles formed by aggregation of primary particles, or a mixture of primary particles and secondary particles (see FIG. 1).
- the primary particles have a particle size of 1.6 to 2.3 ⁇ m.
- the particle size of the primary particles is less than 1.6 ⁇ m, there arises a problem that the particles are cracked by a press during battery production or are deteriorated due to particle cracks during battery cycle.
- the particle size of the primary particles is more than 2.3 ⁇ m, there is a problem of battery deterioration due to the withering of the electrolytic solution or increasing the amount of the electrolytic solution.
- the particle size of the primary particles is preferably 1.8 to 2.1 ⁇ m.
- the positive electrode active material for a lithium ion battery of the present invention has a carbon content measured by the LECO method of 0.40% by mass or less.
- the LECO method is an inert gas melting-infrared absorption method, and is defined in, for example, JIS R 1603.
- the amount of carbon measured by the LECO method is preferably 0.30% by mass or less, more preferably 0.20% by mass or less.
- the carbon contained in the positive electrode material does not exist alone in the inside or on the surface of the positive electrode material, but is present as lithium carbonate (Li 2 CO 3 ).
- Lithium carbonate is a weak alkali and lowers battery characteristics, so it is better that the residual alkali is less.
- “the amount of carbon contained in the positive electrode active material” indicates the amount of carbon contained in the form of lithium carbonate (Li 2 CO 3 ) in the positive electrode material, and if this amount is small ( If it is 0.40 mass% or less), battery characteristics are good.
- the amount of lithium carbonate that is residual alkali on the particle surface measured by neutralization titration is 0.70% by mass or less.
- Neutralization titration is performed using a normal neutralization titration method using hydrochloric acid or the like as a titrant. If the amount of lithium carbonate, which is residual alkali on the particle surface, is more than 0.7% by mass, it reacts with the electrolyte solution during repeated charge and discharge, resulting in deterioration and poor battery characteristics. Moreover, when there is much alkali, gas generation
- the amount of lithium carbonate that is residual alkali on the particle surface measured by neutralization titration is preferably 0.60% by mass or less, more preferably 0.55% by mass or less.
- the positive electrode active material for a lithium ion battery is composed of primary particles, secondary particles formed by aggregation of primary particles, or a mixture of primary particles and secondary particles.
- the positive electrode active material for a lithium ion battery preferably has an average particle diameter of primary particles or secondary particles of 2 to 15 ⁇ m. When the average particle size is less than 2 ⁇ m, it becomes difficult to apply to the current collector. When the average particle size is more than 15 ⁇ m, voids are likely to occur during filling, and the filling property is lowered.
- the average particle size is more preferably 3 to 10 ⁇ m.
- the positive electrode for a lithium ion battery includes, for example, a positive electrode mixture prepared by mixing a positive electrode active material for a lithium ion battery having the above-described configuration, a conductive additive, and a binder from an aluminum foil or the like.
- the current collector has a structure provided on one side or both sides.
- the lithium ion battery which concerns on embodiment of this invention is equipped with the positive electrode for lithium ion batteries of such a structure.
- a metal salt solution is prepared.
- the metal is at least one selected from Ni and Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Ga, Ge, Bi, Sn, Mg, Ca, B, and Zr.
- the metal salt is sulfate, chloride, nitrate, acetate, etc., and nitrate is particularly preferable.
- each metal contained in the metal salt is adjusted so as to have a desired molar ratio. Thereby, the molar ratio of each metal in the positive electrode active material is determined.
- lithium carbonate is suspended in pure water, and then the metal salt solution of the metal is added to prepare a metal carbonate solution slurry. At this time, fine particles of lithium-containing carbonate precipitate in the slurry. At this time, stirring is performed in order to mix the lithium carbonate and the metal salt solution. However, the more the stirring is performed, the smaller the particles of the slurry that are generated, and the more uniform and better the reaction proceeds. The amount of lithium carbonate can be reduced, whereby the carbon content in the lithium salt composite (precursor for lithium ion battery positive electrode material) produced can be suppressed. As a stirring condition, the solution is stirred at a rotation speed of about 250 rpm using a stirring blade having a predetermined size.
- the lithium compound does not react as a metal salt during heat treatment such as sulfate or chloride, the salt is washed with a saturated lithium carbonate solution and then filtered off.
- a saturated lithium carbonate solution When the lithium compound reacts as a lithium raw material during the heat treatment, such as nitrate or acetate, it can be used as a calcined precursor by washing and drying as it is without washing. Next, the lithium-containing carbonate separated by filtration is dried to obtain a lithium salt composite (precursor for lithium ion battery positive electrode material) powder.
- a firing container having a predetermined capacity is prepared, and this firing container is filled with a precursor powder for a lithium ion battery positive electrode material.
- the firing container filled with the precursor powder for the lithium ion battery positive electrode material is transferred to a firing furnace and fired. Firing is performed by heating and holding in an oxygen atmosphere for a predetermined time. Further, it is preferable to perform baking under a pressure of 101 to 202 KPa because the amount of oxygen in the composition further increases.
- the heating and holding temperature in the firing step affects the primary particle size of the lithium ion battery positive electrode material.
- the reactivity is weak compared with the case where lithium hydroxide is used as a raw material.
- the particle size of the primary particles is controlled to 1.6 to 2.3 ⁇ m.
- the firing temperature is lowered because the reactivity is high, and the firing time is reduced. Therefore, the primary particle size to be generated is as small as about 0.5 ⁇ m. End up.
- the powder is taken out from the firing container and pulverized using a commercially available pulverizer or the like to obtain a positive electrode active material powder.
- the crushing at this time is performed by appropriately adjusting the crushing strength and crushing time so that fine powder is not generated as much as possible.
- D90 the particle diameter ( ⁇ m) at the point where the cumulative curve becomes 90%
- D10 the particle diameter ( ⁇ m) at the point where the cumulative curve becomes 10% by the crushing
- (D90 ⁇ D10) / 2 is adjusted to 8 ⁇ m or less. Further, it is more preferable to adjust so that (D90-D10) / 2 is 6 ⁇ m or less.
- Examples 1 to 14 First, after suspending lithium carbonate of the input amount shown in Table 1 in 3.2 liters of pure water, 4.8 liter of metal salt solution was charged. Here, the nitrate hydrate of each metal was adjusted so that each metal might become the composition ratio of Table 1, and the total metal mole number might be set to 14 mol. Stirring was performed using a stirrer equipped with stirring blades at a rotational speed of 250 rpm. Incidentally, a suspension of lithium carbonate, the product (lithium ion secondary battery positive electrode material, i.e.
- A is 0.9 when lithium salt reacts as a firing raw material such as nitrate or acetate, and “1” when lithium salt does not react as a firing raw material such as sulfate or chloride. 0.
- fine particles of lithium-containing carbonate were precipitated in the solution, and this precipitate was filtered off using a filter press. Subsequently, the precipitate was dried to obtain a lithium-containing carbonate (a precursor for a lithium ion battery positive electrode material).
- a firing container was prepared, and this firing container was filled with a lithium-containing carbonate. Next, the firing container was placed in an oxygen atmosphere furnace under atmospheric pressure, heated and held at the firing temperature shown in Table 1 for 10 hours, and then cooled to obtain an oxide.
- the obtained oxide is crushed so that the fine powder having a predetermined particle size has a predetermined particle size distribution width, and a lithium ion secondary battery is obtained.
- a positive electrode powder was obtained.
- Example 15 Example 15 was carried out except that each material of the raw material had the composition shown in Table 1, the metal salt was chloride, the lithium-containing carbonate was precipitated, washed with a saturated lithium carbonate solution, and filtered. The same treatment as in Examples 1 to 14 was performed.
- Example 16 Example 16 was carried out except that each metal of the raw material had a composition as shown in Table 1, the metal salt was a sulfate, a lithium-containing carbonate was precipitated, washed with a saturated lithium carbonate solution, and filtered. The same treatment as in Examples 1 to 14 was performed.
- Example 17 As Example 17, the same processing as in Examples 1 to 14 was performed, except that each metal of the raw material had a composition as shown in Table 1 and firing was performed under a pressure of 120 KPa instead of atmospheric pressure.
- each metal of the raw material has a composition as shown in Table 1, the stirring condition in the reaction between lithium carbonate and the metal salt solution is 150 rpm, and the final oxide is crushed. The same processing as in Examples 1 to 14 was performed except that the adjustment as in Examples 1 to 14 was not performed.
- Comparative Examples 4 to 5 As Comparative Examples 4 to 5, the same processing as in Comparative Example 1 was performed except that each metal of the raw material had a composition as shown in Table 1 and the firing process was performed in an air atmosphere furnace instead of an oxygen atmosphere furnace.
- the amount of carbon in the positive electrode material was measured by the LECO method based on the provisions of JIS G1211, JIS G1215. That is, 0.1 to 0.3 g of powder of each positive electrode material was sampled, 2 g of an auxiliary combustion material not containing carbon was added and placed in a ceramic crucible, and then burned in a high frequency melting furnace. The amount of carbon was determined by detecting and quantifying the components during combustion with an infrared detector.
- Each positive electrode material, conductive material, and binder are weighed in a ratio of 85: 8: 7, and the positive electrode material and the conductive material are mixed into a slurry in which the binder is dissolved in an organic solvent (N-methylpyrrolidone). And coated on an Al foil, dried and pressed to obtain a positive electrode. Subsequently, a 2032 type coin cell for evaluation with Li as the counter electrode was prepared, and 1M-LiPF 6 dissolved in EC-DMC (1: 1) was used as the electrolyte, and the current density was 0.2C. The discharge capacity was measured.
- Examples 1 to 17 all had good battery characteristics. In addition, Examples 1 to 14 and 17 in which the metal salt of the raw material was nitrate had particularly good battery characteristics. Further, Example 17 in which the firing was performed under pressure rather than atmospheric pressure had the best battery characteristics. In Comparative Examples 1 to 3, the composition of the metal used as the raw material was excessive oxygen as in the present invention, but the battery characteristics were poor due to the stirring conditions and crushing conditions. . In Comparative Examples 4 to 5, the composition of the metal used as the raw material was outside the scope of the present invention, and the battery characteristics were poor due to the stirring conditions and the crushing conditions.
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Abstract
Provided is a positive electrode active material for a lithium-ion battery that exhibits excellent battery characteristics. The positive electrode active material for the lithium-ion battery is represented by the composition formula Li (Lix Ni1-x-y My) O2+
α (in the formula, M is one or more elements selected from Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Ga, Ge, Bi, Sn, Mg, Ca, B, and Zr, with 0≤x≤0.1, 0<y≤0.7, and α>0). The primary particle size is 1.6-2.3 μm, the carbon content as measured by the LECO method is 0.40 mass% or lower, and the lithium carbonate content that is the residual alkali of particle surfaces as measured by neutralization titration is 0.70 mass% or lower.
Description
本発明は、リチウムイオン電池用正極活物質、リチウムイオン電池用正極、及び、リチウムイオン電池に関する。
The present invention relates to a positive electrode active material for a lithium ion battery, a positive electrode for a lithium ion battery, and a lithium ion battery.
リチウムイオン電池の正極活物質には、一般にリチウム含有遷移金属酸化物が用いられている。具体的には、コバルト酸リチウム(LiCoO2)、ニッケル酸リチウム(LiNiO2)、マンガン酸リチウム(LiMn2O4)等であり、特性改善(高容量化、サイクル特性、保存特性、内部抵抗低減、レート特性)や安全性を高めるためにこれらを複合化することが進められている。車載用やロードレベリング用といった大型用途におけるリチウムイオン電池には、これまでの携帯電話用やパソコン用とは異なった特性が求められている。
Lithium-containing transition metal oxides are generally used as positive electrode active materials for lithium ion batteries. Specifically, lithium cobaltate (LiCoO 2 ), lithium nickelate (LiNiO 2 ), lithium manganate (LiMn 2 O 4 ), etc., improved characteristics (higher capacity, cycle characteristics, storage characteristics, reduced internal resistance) In order to improve the rate characteristics and safety, it is underway to combine them. Lithium ion batteries for large-scale applications such as in-vehicle use and load leveling are required to have different characteristics from those of conventional mobile phones and personal computers.
電池特性の改善には、従来、種々の方法が用いられており、例えば特許文献1には、
LixNi1-yMyO2-δ
(0.8≦x≦1.3、0<y≦0.5であり、Mは、Co、Mn、Fe、Cr、V、Ti、Cu、Al、Ga、Bi、Sn、Zn、Mg、Ge、Nb、Ta、Be、B、Ca、Sc及びZrからなる群から選ばれる少なくとも一種の元素を示し、δは酸素欠損又は酸素過剰量に相当し、-0.1<δ<0.1を表す。)の組成で表されるリチウムニッケル複合酸化物を分級機に通し、粒子径の大きい物と小さい物とに平衡分離粒子径Dh=1~10μmで分離し、粒子径の大きい物と小さい物を、重量比で0:100~100:0で配合することを特徴とするリチウム二次電池用正極材料の製造方法が開示されている。そして、これによれば、レート特性と容量のさまざまなバランスのリチウム二次電池用正極材料を容易に製造できる、と記載されている。 Various methods have been conventionally used to improve battery characteristics. For example, Patent Document 1 discloses:
Li x Ni 1- y My O 2- δ
(0.8 ≦ x ≦ 1.3, 0 <y ≦ 0.5, and M is Co, Mn, Fe, Cr, V, Ti, Cu, Al, Ga, Bi, Sn, Zn, Mg, It represents at least one element selected from the group consisting of Ge, Nb, Ta, Be, B, Ca, Sc and Zr, δ corresponds to oxygen deficiency or oxygen excess, −0.1 <δ <0.1 The lithium nickel composite oxide represented by the composition is passed through a classifier and separated into a large particle size and a small particle size with an equilibrium separation particle size Dh = 1 to 10 μm. A method for producing a positive electrode material for a lithium secondary battery, characterized in that small substances are blended at a weight ratio of 0: 100 to 100: 0. And according to this, it is described that the positive electrode material for lithium secondary batteries with various balance of rate characteristics and capacity can be easily manufactured.
LixNi1-yMyO2-δ
(0.8≦x≦1.3、0<y≦0.5であり、Mは、Co、Mn、Fe、Cr、V、Ti、Cu、Al、Ga、Bi、Sn、Zn、Mg、Ge、Nb、Ta、Be、B、Ca、Sc及びZrからなる群から選ばれる少なくとも一種の元素を示し、δは酸素欠損又は酸素過剰量に相当し、-0.1<δ<0.1を表す。)の組成で表されるリチウムニッケル複合酸化物を分級機に通し、粒子径の大きい物と小さい物とに平衡分離粒子径Dh=1~10μmで分離し、粒子径の大きい物と小さい物を、重量比で0:100~100:0で配合することを特徴とするリチウム二次電池用正極材料の製造方法が開示されている。そして、これによれば、レート特性と容量のさまざまなバランスのリチウム二次電池用正極材料を容易に製造できる、と記載されている。 Various methods have been conventionally used to improve battery characteristics. For example, Patent Document 1 discloses:
Li x Ni 1- y My O 2- δ
(0.8 ≦ x ≦ 1.3, 0 <y ≦ 0.5, and M is Co, Mn, Fe, Cr, V, Ti, Cu, Al, Ga, Bi, Sn, Zn, Mg, It represents at least one element selected from the group consisting of Ge, Nb, Ta, Be, B, Ca, Sc and Zr, δ corresponds to oxygen deficiency or oxygen excess, −0.1 <δ <0.1 The lithium nickel composite oxide represented by the composition is passed through a classifier and separated into a large particle size and a small particle size with an equilibrium separation particle size Dh = 1 to 10 μm. A method for producing a positive electrode material for a lithium secondary battery, characterized in that small substances are blended at a weight ratio of 0: 100 to 100: 0. And according to this, it is described that the positive electrode material for lithium secondary batteries with various balance of rate characteristics and capacity can be easily manufactured.
特許文献1に記載のリチウムニッケル複合酸化物は、その組成式中の酸素量が過剰のものであるが、それでもなお高品質のリチウムイオン電池用正極活物質としては改善の余地がある。
Although the lithium nickel composite oxide described in Patent Document 1 has an excessive amount of oxygen in its composition formula, there is still room for improvement as a high-quality positive electrode active material for lithium ion batteries.
そこで、本発明は、良好な電池特性を有するリチウムイオン電池用正極活物質を提供することを課題とする。
Therefore, an object of the present invention is to provide a positive electrode active material for a lithium ion battery having good battery characteristics.
本発明者は、鋭意検討した結果、正極活物質の酸素量及び一次粒子の粒径と電池特性との間に密接な相関関係があることを見出した。すなわち、正極活物質の酸素量がある値以上とし、正極活物質の一次粒子の粒径を適切な範囲に制御することにより、良好な電池特性が得られることを見出した。
また、正極活物質の炭素含有量及び正極活物質の粒子表面の残留アルカリである炭酸リチウム量と、電池特性との間に密接な相関関係があることを見出した。すなわち、正極活物質の炭素含有量がある値以下であるとき、また、正極活物質の粒子表面の炭酸リチウム量がある値以下であるとき、特に良好な電池特性が得られることを見出した。 As a result of intensive studies, the present inventor has found that there is a close correlation between the amount of oxygen of the positive electrode active material, the particle size of the primary particles, and the battery characteristics. That is, it has been found that good battery characteristics can be obtained by setting the positive electrode active material oxygen amount to a certain value or more and controlling the primary particle size of the positive electrode active material within an appropriate range.
Further, the present inventors have found that there is a close correlation between the carbon content of the positive electrode active material and the amount of lithium carbonate that is residual alkali on the particle surface of the positive electrode active material, and the battery characteristics. That is, it has been found that particularly good battery characteristics can be obtained when the carbon content of the positive electrode active material is below a certain value or when the amount of lithium carbonate on the particle surface of the positive electrode active material is below a certain value.
また、正極活物質の炭素含有量及び正極活物質の粒子表面の残留アルカリである炭酸リチウム量と、電池特性との間に密接な相関関係があることを見出した。すなわち、正極活物質の炭素含有量がある値以下であるとき、また、正極活物質の粒子表面の炭酸リチウム量がある値以下であるとき、特に良好な電池特性が得られることを見出した。 As a result of intensive studies, the present inventor has found that there is a close correlation between the amount of oxygen of the positive electrode active material, the particle size of the primary particles, and the battery characteristics. That is, it has been found that good battery characteristics can be obtained by setting the positive electrode active material oxygen amount to a certain value or more and controlling the primary particle size of the positive electrode active material within an appropriate range.
Further, the present inventors have found that there is a close correlation between the carbon content of the positive electrode active material and the amount of lithium carbonate that is residual alkali on the particle surface of the positive electrode active material, and the battery characteristics. That is, it has been found that particularly good battery characteristics can be obtained when the carbon content of the positive electrode active material is below a certain value or when the amount of lithium carbonate on the particle surface of the positive electrode active material is below a certain value.
上記知見を基礎にして完成した本発明は一側面において、
組成式:Li(LixNi1-x-yMy)O2+α
(前記式において、MはSc、Ti、V、Cr、Mn、Fe、Co、Cu、Zn、Ga、Ge、Bi、Sn、Mg、Ca、B及びZrから選択される1種以上であり、0≦x≦0.1であり、0<y≦0.7であり、α>0である。)
で表され、一次粒子の粒径が1.6~2.3μmであり、LECO法により測定された炭素量が0.40質量%以下であり、中和滴定により測定された粒子表面の残留アルカリである炭酸リチウム量が0.70質量%以下であるリチウムイオン電池用正極活物質である。 In one aspect of the present invention completed based on the above knowledge,
Composition formula: Li (Li x Ni 1- xy M y) O 2 + α
(In the above formula, M is at least one selected from Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Ga, Ge, Bi, Sn, Mg, Ca, B and Zr; (0 ≦ x ≦ 0.1, 0 <y ≦ 0.7, and α> 0)
The particle size of the primary particles is 1.6 to 2.3 μm, the carbon amount measured by the LECO method is 0.40% by mass or less, and the residual alkali on the particle surface measured by neutralization titration It is the positive electrode active material for lithium ion batteries whose lithium carbonate amount is 0.70 mass% or less.
組成式:Li(LixNi1-x-yMy)O2+α
(前記式において、MはSc、Ti、V、Cr、Mn、Fe、Co、Cu、Zn、Ga、Ge、Bi、Sn、Mg、Ca、B及びZrから選択される1種以上であり、0≦x≦0.1であり、0<y≦0.7であり、α>0である。)
で表され、一次粒子の粒径が1.6~2.3μmであり、LECO法により測定された炭素量が0.40質量%以下であり、中和滴定により測定された粒子表面の残留アルカリである炭酸リチウム量が0.70質量%以下であるリチウムイオン電池用正極活物質である。 In one aspect of the present invention completed based on the above knowledge,
Composition formula: Li (Li x Ni 1- xy M y) O 2 + α
(In the above formula, M is at least one selected from Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Ga, Ge, Bi, Sn, Mg, Ca, B and Zr; (0 ≦ x ≦ 0.1, 0 <y ≦ 0.7, and α> 0)
The particle size of the primary particles is 1.6 to 2.3 μm, the carbon amount measured by the LECO method is 0.40% by mass or less, and the residual alkali on the particle surface measured by neutralization titration It is the positive electrode active material for lithium ion batteries whose lithium carbonate amount is 0.70 mass% or less.
本発明に係るリチウムイオン電池用正極活物質は一実施形態において、LECO法により測定された炭素量が0.20質量%以下であり、中和滴定により測定された粒子表面の残留アルカリである炭酸リチウム量が0.60質量%以下である。
In one embodiment, the positive electrode active material for a lithium ion battery according to the present invention has a carbon content of 0.20% by mass or less as measured by LECO method, and is a carbonic acid that is residual alkali on the particle surface as measured by neutralization titration. The amount of lithium is 0.60 mass% or less.
本発明に係るリチウムイオン電池用正極活物質は別の実施形態において、Mが、Mn及びCoから選択される1種以上である。
In another embodiment, the positive electrode active material for a lithium ion battery according to the present invention is at least one selected from Mn and Co.
本発明に係るリチウムイオン電池用正極活物質は更に別の実施形態において、組成式において、α>0.05である。
In yet another embodiment, the positive electrode active material for a lithium ion battery according to the present invention has α> 0.05 in the composition formula.
本発明に係るリチウムイオン電池用正極活物質は更に別の実施形態において、組成式において、α>0.1である。
In yet another embodiment, the positive electrode active material for a lithium ion battery according to the present invention has α> 0.1 in the composition formula.
本発明は、別の側面において、本発明に係るリチウムイオン電池用正極活物質を用いたリチウムイオン電池用正極である。
In another aspect, the present invention is a positive electrode for a lithium ion battery using the positive electrode active material for a lithium ion battery according to the present invention.
本発明は、更に別の側面において、本発明に係るリチウムイオン電池用正極を用いたリチウムイオン電池である。
In still another aspect, the present invention is a lithium ion battery using the positive electrode for a lithium ion battery according to the present invention.
本発明によれば、良好な電池特性を有するリチウムイオン電池用正極活物質を提供することができる。
According to the present invention, a positive electrode active material for a lithium ion battery having good battery characteristics can be provided.
(リチウムイオン電池用正極活物質の構成)
本発明のリチウムイオン電池用正極活物質の材料としては、一般的なリチウムイオン電池用正極用の正極活物質として有用な化合物を広く用いることができるが、特に、コバルト酸リチウム(LiCoO2)、ニッケル酸リチウム(LiNiO2)、マンガン酸リチウム(LiMn2O4)等のリチウム含有遷移金属酸化物を用いるのが好ましい。このような材料を用いて作製される本発明のリチウムイオン電池用正極活物質は、
組成式:Li(LixNi1-x-yMy)O2+α
(前記式において、MはSc、Ti、V、Cr、Mn、Fe、Co、Cu、Zn、Ga、Ge、Bi、Sn、Mg、Ca、B及びZrから選択される1種以上であり、0≦x≦0.1であり、0<y≦0.7であり、α>0である。)
で表される。 (Configuration of positive electrode active material for lithium ion battery)
As a material of the positive electrode active material for lithium ion batteries of the present invention, compounds useful as a positive electrode active material for general positive electrodes for lithium ion batteries can be widely used. In particular, lithium cobaltate (LiCoO 2 ), It is preferable to use lithium-containing transition metal oxides such as lithium nickelate (LiNiO 2 ) and lithium manganate (LiMn 2 O 4 ). The positive electrode active material for a lithium ion battery of the present invention produced using such a material is
Composition formula: Li (Li x Ni 1- xy M y) O 2 + α
(In the above formula, M is at least one selected from Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Ga, Ge, Bi, Sn, Mg, Ca, B and Zr; (0 ≦ x ≦ 0.1, 0 <y ≦ 0.7, and α> 0)
It is represented by
本発明のリチウムイオン電池用正極活物質の材料としては、一般的なリチウムイオン電池用正極用の正極活物質として有用な化合物を広く用いることができるが、特に、コバルト酸リチウム(LiCoO2)、ニッケル酸リチウム(LiNiO2)、マンガン酸リチウム(LiMn2O4)等のリチウム含有遷移金属酸化物を用いるのが好ましい。このような材料を用いて作製される本発明のリチウムイオン電池用正極活物質は、
組成式:Li(LixNi1-x-yMy)O2+α
(前記式において、MはSc、Ti、V、Cr、Mn、Fe、Co、Cu、Zn、Ga、Ge、Bi、Sn、Mg、Ca、B及びZrから選択される1種以上であり、0≦x≦0.1であり、0<y≦0.7であり、α>0である。)
で表される。 (Configuration of positive electrode active material for lithium ion battery)
As a material of the positive electrode active material for lithium ion batteries of the present invention, compounds useful as a positive electrode active material for general positive electrodes for lithium ion batteries can be widely used. In particular, lithium cobaltate (LiCoO 2 ), It is preferable to use lithium-containing transition metal oxides such as lithium nickelate (LiNiO 2 ) and lithium manganate (LiMn 2 O 4 ). The positive electrode active material for a lithium ion battery of the present invention produced using such a material is
Composition formula: Li (Li x Ni 1- xy M y) O 2 + α
(In the above formula, M is at least one selected from Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Ga, Ge, Bi, Sn, Mg, Ca, B and Zr; (0 ≦ x ≦ 0.1, 0 <y ≦ 0.7, and α> 0)
It is represented by
本発明のリチウムイオン電池用正極活物質は、酸素が組成式において上記のようにO2+α(α>0)と示され、過剰に含まれており、リチウムイオン電池に用いた場合、容量、レート特性及び容量保持率等の電池特性が良好となる。ここで、αについて、好ましくはα>0.05であり、より好ましくはα>0.1である。
In the positive electrode active material for a lithium ion battery of the present invention, oxygen is expressed as O 2 + α (α> 0) as described above in the composition formula, and is excessively contained. Battery characteristics such as rate characteristics and capacity retention are improved. Here, α is preferably α> 0.05, and more preferably α> 0.1.
リチウムイオン電池用正極活物質は、一次粒子、一次粒子が凝集して形成された二次粒子、又は、一次粒子及び二次粒子の混合物で構成されている(図1参照)。このうち、一次粒子の粒径は1.6~2.3μmである。一次粒子の粒径が1.6μm未満であると、電池作製の際のプレスによる粒子の割れを引き起こしたり、電池のサイクル時の粒子のクラックによる劣化という問題が生じる。また、一次粒子の粒径が2.3μm超えであると、電解液の液枯れや電解液の量を増やすことにより電池劣化という問題が生じる。一次粒子の粒径は、好ましくは1.8~2.1μmである。
The positive electrode active material for lithium ion batteries is composed of primary particles, secondary particles formed by aggregation of primary particles, or a mixture of primary particles and secondary particles (see FIG. 1). Among these, the primary particles have a particle size of 1.6 to 2.3 μm. When the particle size of the primary particles is less than 1.6 μm, there arises a problem that the particles are cracked by a press during battery production or are deteriorated due to particle cracks during battery cycle. Moreover, when the particle size of the primary particles is more than 2.3 μm, there is a problem of battery deterioration due to the withering of the electrolytic solution or increasing the amount of the electrolytic solution. The particle size of the primary particles is preferably 1.8 to 2.1 μm.
本発明のリチウムイオン電池用正極活物質は、LECO法により測定された炭素量が0.40質量%以下である。LECO法は、不活性ガス融解-赤外線吸収法であり、例えばJIS R 1603に規定されている。正極活物質の含有炭素量が0.40質量%超であると、その正極活物質を用いたリチウムイオン電池の電池特性、特にサイクル特性が不良となる。LECO法により測定される炭素量は、好ましくは0.30質量%以下であり、より好ましくは0.20質量%以下である。正極材に含まれる炭素については、正極材の粒子内部や表面に炭素単独で存在するのではなく、炭酸リチウム(Li2CO3)として存在している。炭酸リチウムは、弱アルカリであり、電池特性を低下させるため、残留アルカリは少ない方が良い。このように、本発明において「正極活物質の含有炭素量」とは、正極材中に炭酸リチウム(Li2CO3)の形態で含まれる炭素の量を示しており、この量が少なければ(0.40質量%以下であれば)、電池特性が良好となる。
The positive electrode active material for a lithium ion battery of the present invention has a carbon content measured by the LECO method of 0.40% by mass or less. The LECO method is an inert gas melting-infrared absorption method, and is defined in, for example, JIS R 1603. When the carbon content of the positive electrode active material is more than 0.40% by mass, battery characteristics, particularly cycle characteristics, of a lithium ion battery using the positive electrode active material become poor. The amount of carbon measured by the LECO method is preferably 0.30% by mass or less, more preferably 0.20% by mass or less. The carbon contained in the positive electrode material does not exist alone in the inside or on the surface of the positive electrode material, but is present as lithium carbonate (Li 2 CO 3 ). Lithium carbonate is a weak alkali and lowers battery characteristics, so it is better that the residual alkali is less. Thus, in the present invention, “the amount of carbon contained in the positive electrode active material” indicates the amount of carbon contained in the form of lithium carbonate (Li 2 CO 3 ) in the positive electrode material, and if this amount is small ( If it is 0.40 mass% or less), battery characteristics are good.
本発明のリチウムイオン電池用正極活物質は、中和滴定により測定された粒子表面の残留アルカリである炭酸リチウム量が0.70質量%以下である。中和滴定は、塩酸等を滴定液として通常の中和滴定法を用いて行う。粒子表面の残留アルカリである炭酸リチウム量が0.7質量%超であると、充放電を繰り返すうちに電解液と反応し、劣化が起こり、電池特性が悪くなる。また、アルカリが多いとガス発生がおこり、電池特性の劣化を引き起こす。中和滴定により測定される粒子表面の残留アルカリである炭酸リチウム量は、好ましくは0.60質量%以下であり、より好ましくは0.55量%以下である。
In the positive electrode active material for a lithium ion battery of the present invention, the amount of lithium carbonate that is residual alkali on the particle surface measured by neutralization titration is 0.70% by mass or less. Neutralization titration is performed using a normal neutralization titration method using hydrochloric acid or the like as a titrant. If the amount of lithium carbonate, which is residual alkali on the particle surface, is more than 0.7% by mass, it reacts with the electrolyte solution during repeated charge and discharge, resulting in deterioration and poor battery characteristics. Moreover, when there is much alkali, gas generation | occurrence | production will arise and deterioration of a battery characteristic will be caused. The amount of lithium carbonate that is residual alkali on the particle surface measured by neutralization titration is preferably 0.60% by mass or less, more preferably 0.55% by mass or less.
リチウムイオン電池用正極活物質は、一次粒子、一次粒子が凝集して形成された二次粒子、又は、一次粒子及び二次粒子の混合物で構成されている。リチウムイオン電池用正極活物質は、その一次粒子又は二次粒子の平均粒径が2~15μmであるのが好ましい。
平均粒径が2μm未満であると集電体への塗布が困難となる。平均粒径が15μm超であると充填時に空隙が生じやすくなり、充填性が低下する。また、平均粒径は、より好ましくは3~10μmである。 The positive electrode active material for a lithium ion battery is composed of primary particles, secondary particles formed by aggregation of primary particles, or a mixture of primary particles and secondary particles. The positive electrode active material for a lithium ion battery preferably has an average particle diameter of primary particles or secondary particles of 2 to 15 μm.
When the average particle size is less than 2 μm, it becomes difficult to apply to the current collector. When the average particle size is more than 15 μm, voids are likely to occur during filling, and the filling property is lowered. The average particle size is more preferably 3 to 10 μm.
平均粒径が2μm未満であると集電体への塗布が困難となる。平均粒径が15μm超であると充填時に空隙が生じやすくなり、充填性が低下する。また、平均粒径は、より好ましくは3~10μmである。 The positive electrode active material for a lithium ion battery is composed of primary particles, secondary particles formed by aggregation of primary particles, or a mixture of primary particles and secondary particles. The positive electrode active material for a lithium ion battery preferably has an average particle diameter of primary particles or secondary particles of 2 to 15 μm.
When the average particle size is less than 2 μm, it becomes difficult to apply to the current collector. When the average particle size is more than 15 μm, voids are likely to occur during filling, and the filling property is lowered. The average particle size is more preferably 3 to 10 μm.
(リチウムイオン電池用正極及びそれを用いたリチウムイオン電池の構成)
本発明の実施形態に係るリチウムイオン電池用正極は、例えば、上述の構成のリチウムイオン電池用正極活物質と、導電助剤と、バインダーとを混合して調製した正極合剤をアルミニウム箔等からなる集電体の片面または両面に設けた構造を有している。また、本発明の実施形態に係るリチウムイオン電池は、このような構成のリチウムイオン電池用正極を備えている。 (Configuration of positive electrode for lithium ion battery and lithium ion battery using the same)
The positive electrode for a lithium ion battery according to an embodiment of the present invention includes, for example, a positive electrode mixture prepared by mixing a positive electrode active material for a lithium ion battery having the above-described configuration, a conductive additive, and a binder from an aluminum foil or the like. The current collector has a structure provided on one side or both sides. Moreover, the lithium ion battery which concerns on embodiment of this invention is equipped with the positive electrode for lithium ion batteries of such a structure.
本発明の実施形態に係るリチウムイオン電池用正極は、例えば、上述の構成のリチウムイオン電池用正極活物質と、導電助剤と、バインダーとを混合して調製した正極合剤をアルミニウム箔等からなる集電体の片面または両面に設けた構造を有している。また、本発明の実施形態に係るリチウムイオン電池は、このような構成のリチウムイオン電池用正極を備えている。 (Configuration of positive electrode for lithium ion battery and lithium ion battery using the same)
The positive electrode for a lithium ion battery according to an embodiment of the present invention includes, for example, a positive electrode mixture prepared by mixing a positive electrode active material for a lithium ion battery having the above-described configuration, a conductive additive, and a binder from an aluminum foil or the like. The current collector has a structure provided on one side or both sides. Moreover, the lithium ion battery which concerns on embodiment of this invention is equipped with the positive electrode for lithium ion batteries of such a structure.
(リチウムイオン電池用正極活物質の製造方法)
次に、本発明の実施形態に係るリチウムイオン電池用正極活物質の製造方法について詳細に説明する。
まず、金属塩溶液を作製する。当該金属は、Ni、及び、Sc、Ti、V、Cr、Mn、Fe、Co、Cu、Zn、Ga、Ge、Bi、Sn、Mg、Ca、B及びZrから選択される1種以上である。また、金属塩は硫酸塩、塩化物、硝酸塩、酢酸塩等であり、特に硝酸塩が好ましい。これは、焼成原料中に不純物として混入してもそのまま焼成できるため洗浄工程が省けることと、硝酸塩が酸化剤として機能し、焼成原料中の金属の酸化を促進する働きがあるためである。金属塩に含まれる各金属を所望のモル比率となるように調整しておく。これにより、正極活物質中の各金属のモル比率が決定する。 (Method for producing positive electrode active material for lithium ion battery)
Next, the manufacturing method of the positive electrode active material for lithium ion batteries which concerns on embodiment of this invention is demonstrated in detail.
First, a metal salt solution is prepared. The metal is at least one selected from Ni and Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Ga, Ge, Bi, Sn, Mg, Ca, B, and Zr. . The metal salt is sulfate, chloride, nitrate, acetate, etc., and nitrate is particularly preferable. This is because even if it is mixed as an impurity in the firing raw material, it can be fired as it is, so that the washing step can be omitted, and nitrate functions as an oxidant, and promotes the oxidation of the metal in the firing raw material. Each metal contained in the metal salt is adjusted so as to have a desired molar ratio. Thereby, the molar ratio of each metal in the positive electrode active material is determined.
次に、本発明の実施形態に係るリチウムイオン電池用正極活物質の製造方法について詳細に説明する。
まず、金属塩溶液を作製する。当該金属は、Ni、及び、Sc、Ti、V、Cr、Mn、Fe、Co、Cu、Zn、Ga、Ge、Bi、Sn、Mg、Ca、B及びZrから選択される1種以上である。また、金属塩は硫酸塩、塩化物、硝酸塩、酢酸塩等であり、特に硝酸塩が好ましい。これは、焼成原料中に不純物として混入してもそのまま焼成できるため洗浄工程が省けることと、硝酸塩が酸化剤として機能し、焼成原料中の金属の酸化を促進する働きがあるためである。金属塩に含まれる各金属を所望のモル比率となるように調整しておく。これにより、正極活物質中の各金属のモル比率が決定する。 (Method for producing positive electrode active material for lithium ion battery)
Next, the manufacturing method of the positive electrode active material for lithium ion batteries which concerns on embodiment of this invention is demonstrated in detail.
First, a metal salt solution is prepared. The metal is at least one selected from Ni and Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Ga, Ge, Bi, Sn, Mg, Ca, B, and Zr. . The metal salt is sulfate, chloride, nitrate, acetate, etc., and nitrate is particularly preferable. This is because even if it is mixed as an impurity in the firing raw material, it can be fired as it is, so that the washing step can be omitted, and nitrate functions as an oxidant, and promotes the oxidation of the metal in the firing raw material. Each metal contained in the metal salt is adjusted so as to have a desired molar ratio. Thereby, the molar ratio of each metal in the positive electrode active material is determined.
次に、炭酸リチウムを純水に懸濁させ、その後、上記金属の金属塩溶液を投入して金属炭酸塩溶液スラリーを作製する。この際、スラリー中に微小粒のリチウム含有炭酸塩が析出する。また、このとき、炭酸リチウムと金属塩溶液とを混ぜ合わせるために撹拌するが、撹拌が十分であればあるほど生成するスラリーの粒子が小さくなり、より均一且つ良好に反応が進み、未反応の炭酸リチウム量が少なくすることができ、それによって作製するリチウム塩の複合体(リチウムイオン電池正極材用前駆体)中の炭素含有量を抑制することができる。撹拌条件としては、所定の大きさの攪拌羽根を用いて回転数を250rpm程度で溶液を攪拌させる。
なお、金属塩として硫酸塩や塩化物等熱処理時にそのリチウム化合物が反応しない場合は飽和炭酸リチウム溶液でそれらの塩を洗浄した後、濾別する。硝酸塩や酢酸塩のように、そのリチウム化合物が熱処理中にリチウム原料として反応する場合は洗浄せず、そのまま濾別し、乾燥することにより焼成前駆体として用いることができる。
次に、濾別したリチウム含有炭酸塩を乾燥することにより、リチウム塩の複合体(リチウムイオン電池正極材用前駆体)の粉末を得る。 Next, lithium carbonate is suspended in pure water, and then the metal salt solution of the metal is added to prepare a metal carbonate solution slurry. At this time, fine particles of lithium-containing carbonate precipitate in the slurry. At this time, stirring is performed in order to mix the lithium carbonate and the metal salt solution. However, the more the stirring is performed, the smaller the particles of the slurry that are generated, and the more uniform and better the reaction proceeds. The amount of lithium carbonate can be reduced, whereby the carbon content in the lithium salt composite (precursor for lithium ion battery positive electrode material) produced can be suppressed. As a stirring condition, the solution is stirred at a rotation speed of about 250 rpm using a stirring blade having a predetermined size.
If the lithium compound does not react as a metal salt during heat treatment such as sulfate or chloride, the salt is washed with a saturated lithium carbonate solution and then filtered off. When the lithium compound reacts as a lithium raw material during the heat treatment, such as nitrate or acetate, it can be used as a calcined precursor by washing and drying as it is without washing.
Next, the lithium-containing carbonate separated by filtration is dried to obtain a lithium salt composite (precursor for lithium ion battery positive electrode material) powder.
なお、金属塩として硫酸塩や塩化物等熱処理時にそのリチウム化合物が反応しない場合は飽和炭酸リチウム溶液でそれらの塩を洗浄した後、濾別する。硝酸塩や酢酸塩のように、そのリチウム化合物が熱処理中にリチウム原料として反応する場合は洗浄せず、そのまま濾別し、乾燥することにより焼成前駆体として用いることができる。
次に、濾別したリチウム含有炭酸塩を乾燥することにより、リチウム塩の複合体(リチウムイオン電池正極材用前駆体)の粉末を得る。 Next, lithium carbonate is suspended in pure water, and then the metal salt solution of the metal is added to prepare a metal carbonate solution slurry. At this time, fine particles of lithium-containing carbonate precipitate in the slurry. At this time, stirring is performed in order to mix the lithium carbonate and the metal salt solution. However, the more the stirring is performed, the smaller the particles of the slurry that are generated, and the more uniform and better the reaction proceeds. The amount of lithium carbonate can be reduced, whereby the carbon content in the lithium salt composite (precursor for lithium ion battery positive electrode material) produced can be suppressed. As a stirring condition, the solution is stirred at a rotation speed of about 250 rpm using a stirring blade having a predetermined size.
If the lithium compound does not react as a metal salt during heat treatment such as sulfate or chloride, the salt is washed with a saturated lithium carbonate solution and then filtered off. When the lithium compound reacts as a lithium raw material during the heat treatment, such as nitrate or acetate, it can be used as a calcined precursor by washing and drying as it is without washing.
Next, the lithium-containing carbonate separated by filtration is dried to obtain a lithium salt composite (precursor for lithium ion battery positive electrode material) powder.
次に、所定の大きさの容量を有する焼成容器を準備し、この焼成容器にリチウムイオン電池正極材用前駆体の粉末を充填する。次に、リチウムイオン電池正極材用前駆体の粉末が充填された焼成容器を、焼成炉へ移設し、焼成を行う。焼成は、酸素雰囲気下で所定時間加熱保持することにより行う。また、101~202KPaでの加圧下で焼成を行うと、さらに組成中の酸素量が増加するため、好ましい。
焼成工程における加熱保持温度は、リチウムイオン電池正極材の一次粒子の粒径に影響を与える。本発明では、原料に炭酸リチウムを用いているため、水酸化リチウムを原料として用いる場合に比べて反応性が弱い。従って、高温で長時間の焼成が必要となるが、この高温且つ長時間の焼成によって粒子の結晶性が向上し正極材の一次粒子の粒径が大きくなる。本発明では、原料に炭酸リチウムを用いて、750℃以上で12時間以上の焼成を行うことで、一次粒子の粒径を1.6~2.3μmに制御している。これに対し、水酸化リチウムを原料とする場合、通常、反応性が高いために焼成温度は低下し、焼成時間は少なくなるため、生成する一次粒子の粒径は0.5μm程度と小さくなってしまう。
その後、焼成容器から粉末を取り出し、市販の解砕装置等を用いて解砕を行うことにより正極活物質の粉体を得る。このときの解砕は、微粉がなるべく生じないように適宜解砕強度及び解砕時間を調整して行う。具体的には、当該解砕により、D90:累積カーブが90%となる点の粒子径(μm)、D10:累積カーブが10%となる点の粒子径(μm)としたとき、(D90-D10)/2が8μm以下となるように調整する。また、(D90-D10)/2が6μm以下となるように調整するのがより好ましい。解砕性が良い場合は微粉の発生が少なく、且つ、粗大粉の発生も少ないため、D90は相対的に小さく、D10は相対的に大きい値になる。特に、解砕性が劣る場合は、粒径の小さい領域に長く裾をひく(テールが出来る)状態になり易く、そうするとD10は相対的に小さくなり、結果として(D90-D10)/2が大きくなる。すなわち、(D90-D10)/2は粒度のばらつきが少ないことを示す指標といえる。
本発明では、このように解砕時の微粉の発生を制御することにより、体積当たりの粉末の表面積が減少するため、粒子表面の残留炭酸リチウム量を抑制することができる。 Next, a firing container having a predetermined capacity is prepared, and this firing container is filled with a precursor powder for a lithium ion battery positive electrode material. Next, the firing container filled with the precursor powder for the lithium ion battery positive electrode material is transferred to a firing furnace and fired. Firing is performed by heating and holding in an oxygen atmosphere for a predetermined time. Further, it is preferable to perform baking under a pressure of 101 to 202 KPa because the amount of oxygen in the composition further increases.
The heating and holding temperature in the firing step affects the primary particle size of the lithium ion battery positive electrode material. In this invention, since lithium carbonate is used as a raw material, the reactivity is weak compared with the case where lithium hydroxide is used as a raw material. Therefore, firing at a high temperature for a long time is required, but this high temperature and long-time firing improves the crystallinity of the particles and increases the primary particle size of the positive electrode material. In the present invention, by using lithium carbonate as a raw material and firing at 750 ° C. or more for 12 hours or more, the particle size of the primary particles is controlled to 1.6 to 2.3 μm. On the other hand, when lithium hydroxide is used as a raw material, the firing temperature is lowered because the reactivity is high, and the firing time is reduced. Therefore, the primary particle size to be generated is as small as about 0.5 μm. End up.
Thereafter, the powder is taken out from the firing container and pulverized using a commercially available pulverizer or the like to obtain a positive electrode active material powder. The crushing at this time is performed by appropriately adjusting the crushing strength and crushing time so that fine powder is not generated as much as possible. Specifically, when D90: the particle diameter (μm) at the point where the cumulative curve becomes 90%, and D10: the particle diameter (μm) at the point where the cumulative curve becomes 10% by the crushing, (D90− D10) / 2 is adjusted to 8 μm or less. Further, it is more preferable to adjust so that (D90-D10) / 2 is 6 μm or less. When crushability is good, the generation of fine powder is small and the generation of coarse powder is also small, so that D90 is relatively small and D10 is a relatively large value. In particular, when the crushability is inferior, it tends to be in a state where a long tail is formed (a tail is formed) in a region having a small particle diameter, so that D10 becomes relatively small, and as a result, (D90-D10) / 2 becomes large. Become. That is, (D90-D10) / 2 can be said to be an index indicating that there is little variation in particle size.
In the present invention, by controlling the generation of fine powder at the time of crushing as described above, the surface area of the powder per volume is reduced, so that the amount of residual lithium carbonate on the particle surface can be suppressed.
焼成工程における加熱保持温度は、リチウムイオン電池正極材の一次粒子の粒径に影響を与える。本発明では、原料に炭酸リチウムを用いているため、水酸化リチウムを原料として用いる場合に比べて反応性が弱い。従って、高温で長時間の焼成が必要となるが、この高温且つ長時間の焼成によって粒子の結晶性が向上し正極材の一次粒子の粒径が大きくなる。本発明では、原料に炭酸リチウムを用いて、750℃以上で12時間以上の焼成を行うことで、一次粒子の粒径を1.6~2.3μmに制御している。これに対し、水酸化リチウムを原料とする場合、通常、反応性が高いために焼成温度は低下し、焼成時間は少なくなるため、生成する一次粒子の粒径は0.5μm程度と小さくなってしまう。
その後、焼成容器から粉末を取り出し、市販の解砕装置等を用いて解砕を行うことにより正極活物質の粉体を得る。このときの解砕は、微粉がなるべく生じないように適宜解砕強度及び解砕時間を調整して行う。具体的には、当該解砕により、D90:累積カーブが90%となる点の粒子径(μm)、D10:累積カーブが10%となる点の粒子径(μm)としたとき、(D90-D10)/2が8μm以下となるように調整する。また、(D90-D10)/2が6μm以下となるように調整するのがより好ましい。解砕性が良い場合は微粉の発生が少なく、且つ、粗大粉の発生も少ないため、D90は相対的に小さく、D10は相対的に大きい値になる。特に、解砕性が劣る場合は、粒径の小さい領域に長く裾をひく(テールが出来る)状態になり易く、そうするとD10は相対的に小さくなり、結果として(D90-D10)/2が大きくなる。すなわち、(D90-D10)/2は粒度のばらつきが少ないことを示す指標といえる。
本発明では、このように解砕時の微粉の発生を制御することにより、体積当たりの粉末の表面積が減少するため、粒子表面の残留炭酸リチウム量を抑制することができる。 Next, a firing container having a predetermined capacity is prepared, and this firing container is filled with a precursor powder for a lithium ion battery positive electrode material. Next, the firing container filled with the precursor powder for the lithium ion battery positive electrode material is transferred to a firing furnace and fired. Firing is performed by heating and holding in an oxygen atmosphere for a predetermined time. Further, it is preferable to perform baking under a pressure of 101 to 202 KPa because the amount of oxygen in the composition further increases.
The heating and holding temperature in the firing step affects the primary particle size of the lithium ion battery positive electrode material. In this invention, since lithium carbonate is used as a raw material, the reactivity is weak compared with the case where lithium hydroxide is used as a raw material. Therefore, firing at a high temperature for a long time is required, but this high temperature and long-time firing improves the crystallinity of the particles and increases the primary particle size of the positive electrode material. In the present invention, by using lithium carbonate as a raw material and firing at 750 ° C. or more for 12 hours or more, the particle size of the primary particles is controlled to 1.6 to 2.3 μm. On the other hand, when lithium hydroxide is used as a raw material, the firing temperature is lowered because the reactivity is high, and the firing time is reduced. Therefore, the primary particle size to be generated is as small as about 0.5 μm. End up.
Thereafter, the powder is taken out from the firing container and pulverized using a commercially available pulverizer or the like to obtain a positive electrode active material powder. The crushing at this time is performed by appropriately adjusting the crushing strength and crushing time so that fine powder is not generated as much as possible. Specifically, when D90: the particle diameter (μm) at the point where the cumulative curve becomes 90%, and D10: the particle diameter (μm) at the point where the cumulative curve becomes 10% by the crushing, (D90− D10) / 2 is adjusted to 8 μm or less. Further, it is more preferable to adjust so that (D90-D10) / 2 is 6 μm or less. When crushability is good, the generation of fine powder is small and the generation of coarse powder is also small, so that D90 is relatively small and D10 is a relatively large value. In particular, when the crushability is inferior, it tends to be in a state where a long tail is formed (a tail is formed) in a region having a small particle diameter, so that D10 becomes relatively small, and as a result, (D90-D10) / 2 becomes large. Become. That is, (D90-D10) / 2 can be said to be an index indicating that there is little variation in particle size.
In the present invention, by controlling the generation of fine powder at the time of crushing as described above, the surface area of the powder per volume is reduced, so that the amount of residual lithium carbonate on the particle surface can be suppressed.
以下、本発明及びその利点をより良く理解するための実施例を提供するが、本発明はこれらの実施例に限られるものではない。
Hereinafter, examples for better understanding of the present invention and its advantages will be provided, but the present invention is not limited to these examples.
(実施例1~14)
まず、表1に記載の投入量の炭酸リチウムを純水3.2リットルに懸濁させた後、金属塩溶液を4.8リットル投入した。ここで、金属塩溶液は、各金属の硝酸塩の水和物を、各金属が表1に記載の組成比になるように調整し、また全金属モル数が14モルになるように調整した。攪拌は、攪拌羽根を備えた攪拌機により回転数を250rpmとして行った。
なお、炭酸リチウムの懸濁量は、製品(リチウムイオン二次電池正極材料、すなわち正極活物質)をLi(LixNi1-x-yMy)O2+αでxが表1の値となる量であって、それぞれ次式で算出されたものである。
W(g)=73.9×14×(1+0.5{(1+X)/(1-X)}×A
上記式において、「A」は、析出反応として必要な量の他に、ろ過後の原料に残留する炭酸リチウム以外のリチウム化合物によるリチウムの量をあらかじめ懸濁量から引いておくために掛ける数値である。「A」は、硝酸塩や酢酸塩のように、リチウム塩が焼成原料として反応する場合は0.9であり、硫酸塩や塩化物のように、リチウム塩が焼成原料として反応しない場合は1.0である。
この処理により溶液中に微小粒のリチウム含有炭酸塩が析出したが、この析出物を、フィルタープレスを使用して濾別した。
続いて、析出物を乾燥してリチウム含有炭酸塩(リチウムイオン電池正極材用前駆体)を得た。
次に、焼成容器を準備し、この焼成容器内にリチウム含有炭酸塩を充填した。次に、焼成容器を、大気圧下、酸素雰囲気炉に入れて、表1に記載の焼成温度で10時間加熱保持した後冷却して酸化物を得た。
次に、小型粉砕機(ホソカワミクロン ACM-2EC)を用いて、所定の粒径の微粉が所定の粒度分布の分布幅となるように、得られた酸化物を解砕し、リチウムイオン二次電池正極材の粉末を得た。 (Examples 1 to 14)
First, after suspending lithium carbonate of the input amount shown in Table 1 in 3.2 liters of pure water, 4.8 liter of metal salt solution was charged. Here, the nitrate hydrate of each metal was adjusted so that each metal might become the composition ratio of Table 1, and the total metal mole number might be set to 14 mol. Stirring was performed using a stirrer equipped with stirring blades at a rotational speed of 250 rpm.
Incidentally, a suspension of lithium carbonate, the product (lithium ion secondary battery positive electrode material, i.e. a cathode active material) x with Li (Li x Ni 1-xy M y) O 2 + α becomes a value shown in Table 1 Each of which is calculated by the following equation.
W (g) = 73.9 × 14 × (1 + 0.5 {(1 + X) / (1-X)} × A
In the above formula, “A” is a numerical value to be multiplied in order to subtract the amount of lithium from the lithium compound other than lithium carbonate remaining in the raw material after filtration from the amount of suspension in addition to the amount necessary for the precipitation reaction. is there. “A” is 0.9 when lithium salt reacts as a firing raw material such as nitrate or acetate, and “1” when lithium salt does not react as a firing raw material such as sulfate or chloride. 0.
By this treatment, fine particles of lithium-containing carbonate were precipitated in the solution, and this precipitate was filtered off using a filter press.
Subsequently, the precipitate was dried to obtain a lithium-containing carbonate (a precursor for a lithium ion battery positive electrode material).
Next, a firing container was prepared, and this firing container was filled with a lithium-containing carbonate. Next, the firing container was placed in an oxygen atmosphere furnace under atmospheric pressure, heated and held at the firing temperature shown in Table 1 for 10 hours, and then cooled to obtain an oxide.
Next, using a small pulverizer (Hosokawa Micron ACM-2EC), the obtained oxide is crushed so that the fine powder having a predetermined particle size has a predetermined particle size distribution width, and a lithium ion secondary battery is obtained. A positive electrode powder was obtained.
まず、表1に記載の投入量の炭酸リチウムを純水3.2リットルに懸濁させた後、金属塩溶液を4.8リットル投入した。ここで、金属塩溶液は、各金属の硝酸塩の水和物を、各金属が表1に記載の組成比になるように調整し、また全金属モル数が14モルになるように調整した。攪拌は、攪拌羽根を備えた攪拌機により回転数を250rpmとして行った。
なお、炭酸リチウムの懸濁量は、製品(リチウムイオン二次電池正極材料、すなわち正極活物質)をLi(LixNi1-x-yMy)O2+αでxが表1の値となる量であって、それぞれ次式で算出されたものである。
W(g)=73.9×14×(1+0.5{(1+X)/(1-X)}×A
上記式において、「A」は、析出反応として必要な量の他に、ろ過後の原料に残留する炭酸リチウム以外のリチウム化合物によるリチウムの量をあらかじめ懸濁量から引いておくために掛ける数値である。「A」は、硝酸塩や酢酸塩のように、リチウム塩が焼成原料として反応する場合は0.9であり、硫酸塩や塩化物のように、リチウム塩が焼成原料として反応しない場合は1.0である。
この処理により溶液中に微小粒のリチウム含有炭酸塩が析出したが、この析出物を、フィルタープレスを使用して濾別した。
続いて、析出物を乾燥してリチウム含有炭酸塩(リチウムイオン電池正極材用前駆体)を得た。
次に、焼成容器を準備し、この焼成容器内にリチウム含有炭酸塩を充填した。次に、焼成容器を、大気圧下、酸素雰囲気炉に入れて、表1に記載の焼成温度で10時間加熱保持した後冷却して酸化物を得た。
次に、小型粉砕機(ホソカワミクロン ACM-2EC)を用いて、所定の粒径の微粉が所定の粒度分布の分布幅となるように、得られた酸化物を解砕し、リチウムイオン二次電池正極材の粉末を得た。 (Examples 1 to 14)
First, after suspending lithium carbonate of the input amount shown in Table 1 in 3.2 liters of pure water, 4.8 liter of metal salt solution was charged. Here, the nitrate hydrate of each metal was adjusted so that each metal might become the composition ratio of Table 1, and the total metal mole number might be set to 14 mol. Stirring was performed using a stirrer equipped with stirring blades at a rotational speed of 250 rpm.
Incidentally, a suspension of lithium carbonate, the product (lithium ion secondary battery positive electrode material, i.e. a cathode active material) x with Li (Li x Ni 1-xy M y) O 2 + α becomes a value shown in Table 1 Each of which is calculated by the following equation.
W (g) = 73.9 × 14 × (1 + 0.5 {(1 + X) / (1-X)} × A
In the above formula, “A” is a numerical value to be multiplied in order to subtract the amount of lithium from the lithium compound other than lithium carbonate remaining in the raw material after filtration from the amount of suspension in addition to the amount necessary for the precipitation reaction. is there. “A” is 0.9 when lithium salt reacts as a firing raw material such as nitrate or acetate, and “1” when lithium salt does not react as a firing raw material such as sulfate or chloride. 0.
By this treatment, fine particles of lithium-containing carbonate were precipitated in the solution, and this precipitate was filtered off using a filter press.
Subsequently, the precipitate was dried to obtain a lithium-containing carbonate (a precursor for a lithium ion battery positive electrode material).
Next, a firing container was prepared, and this firing container was filled with a lithium-containing carbonate. Next, the firing container was placed in an oxygen atmosphere furnace under atmospheric pressure, heated and held at the firing temperature shown in Table 1 for 10 hours, and then cooled to obtain an oxide.
Next, using a small pulverizer (Hosokawa Micron ACM-2EC), the obtained oxide is crushed so that the fine powder having a predetermined particle size has a predetermined particle size distribution width, and a lithium ion secondary battery is obtained. A positive electrode powder was obtained.
(実施例15)
実施例15として、原料の各金属を表1に示すような組成とし、金属塩を塩化物とし、リチウム含有炭酸塩を析出させた後、飽和炭酸リチウム溶液で洗浄し、濾過する以外は、実施例1~14と同様の処理を行った。 (Example 15)
Example 15 was carried out except that each material of the raw material had the composition shown in Table 1, the metal salt was chloride, the lithium-containing carbonate was precipitated, washed with a saturated lithium carbonate solution, and filtered. The same treatment as in Examples 1 to 14 was performed.
実施例15として、原料の各金属を表1に示すような組成とし、金属塩を塩化物とし、リチウム含有炭酸塩を析出させた後、飽和炭酸リチウム溶液で洗浄し、濾過する以外は、実施例1~14と同様の処理を行った。 (Example 15)
Example 15 was carried out except that each material of the raw material had the composition shown in Table 1, the metal salt was chloride, the lithium-containing carbonate was precipitated, washed with a saturated lithium carbonate solution, and filtered. The same treatment as in Examples 1 to 14 was performed.
(実施例16)
実施例16として、原料の各金属を表1に示すような組成とし、金属塩を硫酸塩とし、リチウム含有炭酸塩を析出させた後、飽和炭酸リチウム溶液で洗浄し、濾過する以外は、実施例1~14と同様の処理を行った。 (Example 16)
Example 16 was carried out except that each metal of the raw material had a composition as shown in Table 1, the metal salt was a sulfate, a lithium-containing carbonate was precipitated, washed with a saturated lithium carbonate solution, and filtered. The same treatment as in Examples 1 to 14 was performed.
実施例16として、原料の各金属を表1に示すような組成とし、金属塩を硫酸塩とし、リチウム含有炭酸塩を析出させた後、飽和炭酸リチウム溶液で洗浄し、濾過する以外は、実施例1~14と同様の処理を行った。 (Example 16)
Example 16 was carried out except that each metal of the raw material had a composition as shown in Table 1, the metal salt was a sulfate, a lithium-containing carbonate was precipitated, washed with a saturated lithium carbonate solution, and filtered. The same treatment as in Examples 1 to 14 was performed.
(実施例17)
実施例17として、原料の各金属を表1に示すような組成とし、焼成を大気圧下ではなく120KPaの加圧下で行った以外は、実施例1~14と同様の処理を行った。 (Example 17)
As Example 17, the same processing as in Examples 1 to 14 was performed, except that each metal of the raw material had a composition as shown in Table 1 and firing was performed under a pressure of 120 KPa instead of atmospheric pressure.
実施例17として、原料の各金属を表1に示すような組成とし、焼成を大気圧下ではなく120KPaの加圧下で行った以外は、実施例1~14と同様の処理を行った。 (Example 17)
As Example 17, the same processing as in Examples 1 to 14 was performed, except that each metal of the raw material had a composition as shown in Table 1 and firing was performed under a pressure of 120 KPa instead of atmospheric pressure.
(比較例1~3)
比較例1~3として、原料の各金属を表1に示すような組成とし、炭酸リチウムと金属塩溶液との反応における撹拌条件を攪拌羽根の回転数を150rpmとし、最後の酸化物の解砕について実施例1~14のような調整を行わない以外は、実施例1~14と同様の処理を行った。 (Comparative Examples 1 to 3)
As Comparative Examples 1 to 3, each metal of the raw material has a composition as shown in Table 1, the stirring condition in the reaction between lithium carbonate and the metal salt solution is 150 rpm, and the final oxide is crushed. The same processing as in Examples 1 to 14 was performed except that the adjustment as in Examples 1 to 14 was not performed.
比較例1~3として、原料の各金属を表1に示すような組成とし、炭酸リチウムと金属塩溶液との反応における撹拌条件を攪拌羽根の回転数を150rpmとし、最後の酸化物の解砕について実施例1~14のような調整を行わない以外は、実施例1~14と同様の処理を行った。 (Comparative Examples 1 to 3)
As Comparative Examples 1 to 3, each metal of the raw material has a composition as shown in Table 1, the stirring condition in the reaction between lithium carbonate and the metal salt solution is 150 rpm, and the final oxide is crushed. The same processing as in Examples 1 to 14 was performed except that the adjustment as in Examples 1 to 14 was not performed.
(比較例4~5)
比較例4~5として、原料の各金属を表1に示すような組成とし、酸素雰囲気炉ではなく空気雰囲気炉で焼成工程を行った点以外は、比較例1と同様の処理を行った。 (Comparative Examples 4 to 5)
As Comparative Examples 4 to 5, the same processing as in Comparative Example 1 was performed except that each metal of the raw material had a composition as shown in Table 1 and the firing process was performed in an air atmosphere furnace instead of an oxygen atmosphere furnace.
比較例4~5として、原料の各金属を表1に示すような組成とし、酸素雰囲気炉ではなく空気雰囲気炉で焼成工程を行った点以外は、比較例1と同様の処理を行った。 (Comparative Examples 4 to 5)
As Comparative Examples 4 to 5, the same processing as in Comparative Example 1 was performed except that each metal of the raw material had a composition as shown in Table 1 and the firing process was performed in an air atmosphere furnace instead of an oxygen atmosphere furnace.
(評価)
-正極材組成の評価-
各正極材中の金属含有量は、誘導結合プラズマ発光分光分析装置(ICP-OES)で測定し、各金属の組成比(モル比)を算出した。また、酸素含有量はLECO法で測定しαを算出した。これらの結果が表1に記載の通りであることを確認した。 (Evaluation)
-Evaluation of composition of positive electrode material-
The metal content in each positive electrode material was measured with an inductively coupled plasma optical emission spectrometer (ICP-OES), and the composition ratio (molar ratio) of each metal was calculated. The oxygen content was measured by the LECO method and α was calculated. These results were confirmed to be as shown in Table 1.
-正極材組成の評価-
各正極材中の金属含有量は、誘導結合プラズマ発光分光分析装置(ICP-OES)で測定し、各金属の組成比(モル比)を算出した。また、酸素含有量はLECO法で測定しαを算出した。これらの結果が表1に記載の通りであることを確認した。 (Evaluation)
-Evaluation of composition of positive electrode material-
The metal content in each positive electrode material was measured with an inductively coupled plasma optical emission spectrometer (ICP-OES), and the composition ratio (molar ratio) of each metal was calculated. The oxygen content was measured by the LECO method and α was calculated. These results were confirmed to be as shown in Table 1.
-一次粒子の粒径の評価-
各正極材の粉末を採取し、一次粒子の粒径をレーザー回折粒度分布測定機(マイクロトラックMT3300EX II)によって測定した。 -Evaluation of primary particle size-
The powder of each positive electrode material was sampled, and the particle size of the primary particles was measured with a laser diffraction particle size distribution analyzer (Microtrack MT3300EX II).
各正極材の粉末を採取し、一次粒子の粒径をレーザー回折粒度分布測定機(マイクロトラックMT3300EX II)によって測定した。 -Evaluation of primary particle size-
The powder of each positive electrode material was sampled, and the particle size of the primary particles was measured with a laser diffraction particle size distribution analyzer (Microtrack MT3300EX II).
-炭素量の評価-
正極材中の炭素量は、JIS G1211、JIS G1215の規定に基づき、LECO法により測定した。すなわち、各正極材の粉末を0.1~0.3g採取し、炭素を含有していない助燃材2gを加えてセラミック製るつぼへ入れた後、高周波溶解炉によって燃焼させた。燃焼時の成分を赤外線検出器によって検出し、定量することで炭素量を求めた。 -Evaluation of carbon content-
The amount of carbon in the positive electrode material was measured by the LECO method based on the provisions of JIS G1211, JIS G1215. That is, 0.1 to 0.3 g of powder of each positive electrode material was sampled, 2 g of an auxiliary combustion material not containing carbon was added and placed in a ceramic crucible, and then burned in a high frequency melting furnace. The amount of carbon was determined by detecting and quantifying the components during combustion with an infrared detector.
正極材中の炭素量は、JIS G1211、JIS G1215の規定に基づき、LECO法により測定した。すなわち、各正極材の粉末を0.1~0.3g採取し、炭素を含有していない助燃材2gを加えてセラミック製るつぼへ入れた後、高周波溶解炉によって燃焼させた。燃焼時の成分を赤外線検出器によって検出し、定量することで炭素量を求めた。 -Evaluation of carbon content-
The amount of carbon in the positive electrode material was measured by the LECO method based on the provisions of JIS G1211, JIS G1215. That is, 0.1 to 0.3 g of powder of each positive electrode material was sampled, 2 g of an auxiliary combustion material not containing carbon was added and placed in a ceramic crucible, and then burned in a high frequency melting furnace. The amount of carbon was determined by detecting and quantifying the components during combustion with an infrared detector.
-残留炭酸リチウム量の評価-
正極材の粒子表面の残留炭酸リチウム量は、塩酸を滴定液として用い、中和滴定により測定した。 -Evaluation of residual lithium carbonate amount-
The amount of residual lithium carbonate on the particle surface of the positive electrode material was measured by neutralization titration using hydrochloric acid as a titrant.
正極材の粒子表面の残留炭酸リチウム量は、塩酸を滴定液として用い、中和滴定により測定した。 -Evaluation of residual lithium carbonate amount-
The amount of residual lithium carbonate on the particle surface of the positive electrode material was measured by neutralization titration using hydrochloric acid as a titrant.
-電池特性の評価-
各正極材と、導電材と、バインダーとを85:8:7の割合で秤量し、バインダーを有機溶媒(N-メチルピロリドン)に溶解したものに、正極材料と導電材とを混合してスラリー化し、Al箔上に塗布して乾燥後にプレスして正極とした。続いて、対極をLiとした評価用の2032型コインセルを作製し、電解液に1M-LiPF6をEC-DMC(1:1)に溶解したものを用いて、電流密度0.2Cの際の放電容量を測定した。また電流密度0.2Cのときの電池容量に対する電流密度2Cのときの、放電容量の比を算出してレート特性を得た。さらに、容量保持率は、室温で1Cの放電電流で得られた初期放電容量と100サイクル後の放電容量を比較することによって測定した。
これらの結果を表1及び2に示す。 -Evaluation of battery characteristics-
Each positive electrode material, conductive material, and binder are weighed in a ratio of 85: 8: 7, and the positive electrode material and the conductive material are mixed into a slurry in which the binder is dissolved in an organic solvent (N-methylpyrrolidone). And coated on an Al foil, dried and pressed to obtain a positive electrode. Subsequently, a 2032 type coin cell for evaluation with Li as the counter electrode was prepared, and 1M-LiPF 6 dissolved in EC-DMC (1: 1) was used as the electrolyte, and the current density was 0.2C. The discharge capacity was measured. Further, a rate characteristic was obtained by calculating a ratio of the discharge capacity when the current density was 2C to the battery capacity when the current density was 0.2C. Furthermore, the capacity retention was measured by comparing the initial discharge capacity obtained with a 1 C discharge current at room temperature with the discharge capacity after 100 cycles.
These results are shown in Tables 1 and 2.
各正極材と、導電材と、バインダーとを85:8:7の割合で秤量し、バインダーを有機溶媒(N-メチルピロリドン)に溶解したものに、正極材料と導電材とを混合してスラリー化し、Al箔上に塗布して乾燥後にプレスして正極とした。続いて、対極をLiとした評価用の2032型コインセルを作製し、電解液に1M-LiPF6をEC-DMC(1:1)に溶解したものを用いて、電流密度0.2Cの際の放電容量を測定した。また電流密度0.2Cのときの電池容量に対する電流密度2Cのときの、放電容量の比を算出してレート特性を得た。さらに、容量保持率は、室温で1Cの放電電流で得られた初期放電容量と100サイクル後の放電容量を比較することによって測定した。
これらの結果を表1及び2に示す。 -Evaluation of battery characteristics-
Each positive electrode material, conductive material, and binder are weighed in a ratio of 85: 8: 7, and the positive electrode material and the conductive material are mixed into a slurry in which the binder is dissolved in an organic solvent (N-methylpyrrolidone). And coated on an Al foil, dried and pressed to obtain a positive electrode. Subsequently, a 2032 type coin cell for evaluation with Li as the counter electrode was prepared, and 1M-LiPF 6 dissolved in EC-DMC (1: 1) was used as the electrolyte, and the current density was 0.2C. The discharge capacity was measured. Further, a rate characteristic was obtained by calculating a ratio of the discharge capacity when the current density was 2C to the battery capacity when the current density was 0.2C. Furthermore, the capacity retention was measured by comparing the initial discharge capacity obtained with a 1 C discharge current at room temperature with the discharge capacity after 100 cycles.
These results are shown in Tables 1 and 2.
(評価)
実施例1~17は、いずれも電池特性が良好であった。また、原料の金属塩を硝酸塩とした実施例1~14、17は特に電池特性が良好であった。さらに、焼成を大気圧下ではなく加圧下で行った実施例17は最も電池特性が良好であった。
比較例1~3は、原料とした金属の組成は本発明と同様に酸素が過剰に含まれているものであったが、攪拌条件及び解砕条件が原因で、電池特性が不良であった。比較例4~5は、原料とした金属の組成が本発明の範囲外のものであり、さらに攪拌条件及び解砕条件が原因で、電池特性が不良であった。 (Evaluation)
Examples 1 to 17 all had good battery characteristics. In addition, Examples 1 to 14 and 17 in which the metal salt of the raw material was nitrate had particularly good battery characteristics. Further, Example 17 in which the firing was performed under pressure rather than atmospheric pressure had the best battery characteristics.
In Comparative Examples 1 to 3, the composition of the metal used as the raw material was excessive oxygen as in the present invention, but the battery characteristics were poor due to the stirring conditions and crushing conditions. . In Comparative Examples 4 to 5, the composition of the metal used as the raw material was outside the scope of the present invention, and the battery characteristics were poor due to the stirring conditions and the crushing conditions.
実施例1~17は、いずれも電池特性が良好であった。また、原料の金属塩を硝酸塩とした実施例1~14、17は特に電池特性が良好であった。さらに、焼成を大気圧下ではなく加圧下で行った実施例17は最も電池特性が良好であった。
比較例1~3は、原料とした金属の組成は本発明と同様に酸素が過剰に含まれているものであったが、攪拌条件及び解砕条件が原因で、電池特性が不良であった。比較例4~5は、原料とした金属の組成が本発明の範囲外のものであり、さらに攪拌条件及び解砕条件が原因で、電池特性が不良であった。 (Evaluation)
Examples 1 to 17 all had good battery characteristics. In addition, Examples 1 to 14 and 17 in which the metal salt of the raw material was nitrate had particularly good battery characteristics. Further, Example 17 in which the firing was performed under pressure rather than atmospheric pressure had the best battery characteristics.
In Comparative Examples 1 to 3, the composition of the metal used as the raw material was excessive oxygen as in the present invention, but the battery characteristics were poor due to the stirring conditions and crushing conditions. . In Comparative Examples 4 to 5, the composition of the metal used as the raw material was outside the scope of the present invention, and the battery characteristics were poor due to the stirring conditions and the crushing conditions.
Claims (7)
- 組成式:Li(LixNi1-x-yMy)O2+α
(前記式において、MはSc、Ti、V、Cr、Mn、Fe、Co、Cu、Zn、Ga、Ge、Bi、Sn、Mg、Ca、B及びZrから選択される1種以上であり、0≦x≦0.1であり、0<y≦0.7であり、α>0である。)
で表され、
一次粒子の粒径が1.6~2.3μmであり、
LECO法により測定された炭素量が0.40質量%以下であり、中和滴定により測定された粒子表面の残留アルカリである炭酸リチウム量が0.70質量%以下であるリチウムイオン電池用正極活物質。 Composition formula: Li (Li x Ni 1- xy M y) O 2 + α
(In the above formula, M is at least one selected from Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Ga, Ge, Bi, Sn, Mg, Ca, B and Zr; (0 ≦ x ≦ 0.1, 0 <y ≦ 0.7, and α> 0)
Represented by
The primary particles have a particle size of 1.6 to 2.3 μm,
The positive electrode active for lithium ion batteries in which the amount of carbon measured by the LECO method is 0.40% by mass or less and the amount of lithium carbonate that is residual alkali on the particle surface measured by neutralization titration is 0.70% by mass or less. material. - LECO法により測定された炭素量が0.20質量%以下であり、中和滴定により測定された粒子表面の残留アルカリである炭酸リチウム量が0.60質量%以下である請求項1に記載のリチウムイオン電池用正極活物質。 The amount of carbon as measured by LECO method is 0.20% by mass or less, and the amount of lithium carbonate as residual alkali on the particle surface measured by neutralization titration is 0.60% by mass or less. Positive electrode active material for lithium ion batteries.
- 前記Mが、Mn及びCoから選択される1種以上である請求項1又は2に記載のリチウムイオン電池用正極活物質。 The positive electrode active material for a lithium ion battery according to claim 1 or 2, wherein the M is at least one selected from Mn and Co.
- 前記組成式において、α>0.05である請求項1~3のいずれかに記載のリチウムイオン電池用正極活物質。 4. The positive electrode active material for a lithium ion battery according to claim 1, wherein α> 0.05 in the composition formula.
- 前記組成式において、α>0.1である請求項4に記載のリチウムイオン電池用正極活物質。 The positive electrode active material for a lithium ion battery according to claim 4, wherein α> 0.1 in the composition formula.
- 請求項1~5のいずれかに記載のリチウムイオン電池用正極活物質を用いたリチウムイオン電池用正極。 A positive electrode for a lithium ion battery using the positive electrode active material for a lithium ion battery according to any one of claims 1 to 5.
- 請求項6に記載のリチウムイオン電池用正極を用いたリチウムイオン電池。 A lithium ion battery using the positive electrode for a lithium ion battery according to claim 6.
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