JP7421372B2 - Method for manufacturing positive electrode active material composite for lithium ion secondary battery - Google Patents
Method for manufacturing positive electrode active material composite for lithium ion secondary battery Download PDFInfo
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- JP7421372B2 JP7421372B2 JP2020033710A JP2020033710A JP7421372B2 JP 7421372 B2 JP7421372 B2 JP 7421372B2 JP 2020033710 A JP2020033710 A JP 2020033710A JP 2020033710 A JP2020033710 A JP 2020033710A JP 7421372 B2 JP7421372 B2 JP 7421372B2
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- Prior art keywords
- lithium
- particles
- positive electrode
- composite
- electrode active
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- 239000002131 composite material Substances 0.000 title claims description 176
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims description 73
- 229910001416 lithium ion Inorganic materials 0.000 title claims description 73
- 239000007774 positive electrode material Substances 0.000 title claims description 67
- 238000004519 manufacturing process Methods 0.000 title claims description 49
- 238000000034 method Methods 0.000 title claims description 27
- 229910052744 lithium Inorganic materials 0.000 claims description 152
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 150
- 239000002245 particle Substances 0.000 claims description 117
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- 239000011163 secondary particle Substances 0.000 claims description 66
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 55
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- 239000002002 slurry Substances 0.000 claims description 40
- 238000002156 mixing Methods 0.000 claims description 32
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- 239000003960 organic solvent Substances 0.000 claims description 25
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- 239000011702 manganese sulphate Substances 0.000 description 1
- 235000007079 manganese sulphate Nutrition 0.000 description 1
- UOGMEBQRZBEZQT-UHFFFAOYSA-L manganese(2+);diacetate Chemical compound [Mn+2].CC([O-])=O.CC([O-])=O UOGMEBQRZBEZQT-UHFFFAOYSA-L 0.000 description 1
- MIVBAHRSNUNMPP-UHFFFAOYSA-N manganese(2+);dinitrate Chemical compound [Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MIVBAHRSNUNMPP-UHFFFAOYSA-N 0.000 description 1
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 description 1
- SCVOEYLBXCPATR-UHFFFAOYSA-L manganese(II) sulfate pentahydrate Chemical compound O.O.O.O.O.[Mn+2].[O-]S([O-])(=O)=O SCVOEYLBXCPATR-UHFFFAOYSA-L 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- DRLFMBDRBRZALE-UHFFFAOYSA-N melatonin Chemical compound COC1=CC=C2NC=C(CCNC(C)=O)C2=C1 DRLFMBDRBRZALE-UHFFFAOYSA-N 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 150000002772 monosaccharides Chemical class 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 1
- 239000007773 negative electrode material Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- RRIWRJBSCGCBID-UHFFFAOYSA-L nickel sulfate hexahydrate Chemical compound O.O.O.O.O.O.[Ni+2].[O-]S([O-])(=O)=O RRIWRJBSCGCBID-UHFFFAOYSA-L 0.000 description 1
- 229940116202 nickel sulfate hexahydrate Drugs 0.000 description 1
- 150000002825 nitriles Chemical class 0.000 description 1
- 239000010450 olivine Substances 0.000 description 1
- 229910052609 olivine Inorganic materials 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 150000003016 phosphoric acids Chemical class 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920001282 polysaccharide Polymers 0.000 description 1
- 239000005017 polysaccharide Substances 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- ULWHHBHJGPPBCO-UHFFFAOYSA-N propane-1,1-diol Chemical compound CCC(O)O ULWHHBHJGPPBCO-UHFFFAOYSA-N 0.000 description 1
- 229940005657 pyrophosphoric acid Drugs 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000000790 scattering method Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000008107 starch Substances 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 235000002906 tartaric acid Nutrition 0.000 description 1
- 239000011975 tartaric acid Substances 0.000 description 1
- RBTVSNLYYIMMKS-UHFFFAOYSA-N tert-butyl 3-aminoazetidine-1-carboxylate;hydrochloride Chemical compound Cl.CC(C)(C)OC(=O)N1CC(N)C1 RBTVSNLYYIMMKS-UHFFFAOYSA-N 0.000 description 1
- 150000007984 tetrahydrofuranes Chemical class 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- UNXRWKVEANCORM-UHFFFAOYSA-N triphosphoric acid Chemical compound OP(O)(=O)OP(O)(=O)OP(O)(O)=O UNXRWKVEANCORM-UHFFFAOYSA-N 0.000 description 1
- 229940048102 triphosphoric acid Drugs 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
Classifications
-
- 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
Description
本発明は、優れた電池特性と安全性を兼ね備えたリチウムイオン二次電池用正極活物質複合体の製造方法に関する。 The present invention relates to a method for producing a positive electrode active material composite for lithium ion secondary batteries that has both excellent battery characteristics and safety.
従来より、リチウム複合酸化物は高出力及び高容量のリチウムイオン二次電池を構成できる正極活物質として使用されている。かかるリチウム複合酸化物は、リチウム原子層と遷移金属原子層とが、酸素原子層を介して交互に積み重なった層状結晶構造を呈し、遷移金属の１原子あたりに１個のリチウム原子が含まれる、いわゆる層状岩塩構造を有することでも知られている。 Conventionally, lithium composite oxides have been used as positive electrode active materials that can constitute high-output and high-capacity lithium ion secondary batteries. Such a lithium composite oxide exhibits a layered crystal structure in which lithium atomic layers and transition metal atomic layers are stacked alternately with oxygen atomic layers interposed therebetween, and one lithium atom is contained per transition metal atom. It is also known for having a so-called layered rock salt structure.
こうしたリチウム複合酸化物を正極活物質として用いたリチウムイオン二次電池では、リチウムイオンがリチウム複合酸化物に脱離・挿入されることによって充電・放電が行われるが、通常、充放電サイクルを重ねるにつれて容量低下が生じ、特に長期間使用すると、電池の容量低下が著しくなるおそれがある。これは、充電時にリチウム複合酸化物の遷移金属成分が電解液へ溶出することにより、かかる結晶構造の崩壊が生じやすくなることが原因であると考えられている。また、リチウム複合酸化物の結晶構造の崩壊が生じると、リチウム複合酸化物の遷移金属成分が周囲の電解液へ溶出し、熱的安定性が低下して安全性が損なわれるおそれもある。 In lithium ion secondary batteries that use such lithium composite oxide as the positive electrode active material, charging and discharging are performed by desorption and insertion of lithium ions into the lithium composite oxide, but normally charge and discharge cycles are repeated. As the battery ages, the capacity decreases, and especially when used for a long period of time, there is a risk that the capacity decrease of the battery will become significant. This is thought to be because the transition metal component of the lithium composite oxide is eluted into the electrolyte during charging, making the crystal structure more likely to collapse. Furthermore, if the crystal structure of the lithium composite oxide collapses, the transition metal component of the lithium composite oxide will be eluted into the surrounding electrolyte, which may reduce thermal stability and impair safety.
こうしたなか、より優れた電池特性を有するリチウムイオン二次電池を実現すべく、種々の正極活物質材料が開発されている。例えば、特許文献１には、核となる二次粒子が特定の組成及び平均二次粒子径を有するＬｉ－Ｎｉ複合酸化物において、二次粒子の表面に特定の組成であるＬｉ－Ｎｉ複合酸化物を被覆又は存在させたＬｉ－Ｎｉ複合酸化物粒子粉末が開示されており、かかる粉末の製造方法として、湿式による化学的処理、又は乾式による機械的処理等によりＬｉ－Ｎｉ複合酸化物を被覆又は存在させる技術も開示されている。 Under these circumstances, various positive electrode active materials have been developed in order to realize lithium ion secondary batteries with better battery characteristics. For example, in Patent Document 1, in a Li-Ni composite oxide in which the secondary particles serving as the core have a specific composition and an average secondary particle diameter, Li-Ni composite oxide with a specific composition is coated on the surface of the secondary particles. A Li-Ni composite oxide particle powder coated with or in the presence of a substance is disclosed, and as a method for producing such powder, the Li-Ni composite oxide is coated by a wet chemical treatment, a dry mechanical treatment, etc. Alternatively, a technique for making it exist is also disclosed.
しかしながら、リチウムイオン二次電池に水分が混入すると、電解液に含まれるＬｉＰＦ６と水分が反応することによりフッ酸が発生し、電池性能の劣化の原因となるため、リチウムイオン二次電池正極活物質に含まれる水分は低減することが必要である。しかしながら、上記特許文献に記載される湿式法による化学的処理では、得られる正極活物質材料中における水分を充分に低減できないおそれがある。
一方、乾式法により正極活物質材料を得る場合、正極活物質材料が大気中の水分を吸着しやすいため、低湿度雰囲気中での機械的処理が必要となる。しかしながら、上記特許文献に記載される乾式法による機械的処理であると、装置や湿度管理等の煩雑化が避けられず、工業的な実施には依然として困難を伴う状況にある。
However, if water enters a lithium ion secondary battery, the water reacts with LiPF 6 contained in the electrolyte, generating hydrofluoric acid, which causes deterioration of battery performance. It is necessary to reduce the moisture content of substances. However, the chemical treatment using the wet method described in the above-mentioned patent document may not be able to sufficiently reduce the water content in the resulting positive electrode active material.
On the other hand, when obtaining a positive electrode active material by a dry method, mechanical treatment in a low humidity atmosphere is required because the positive electrode active material easily adsorbs moisture in the atmosphere. However, the mechanical treatment using the dry method described in the above-mentioned patent documents inevitably complicates the equipment, humidity control, etc., and is still difficult to implement industrially.
したがって、本発明の課題は、リチウムイオン二次電池用正極活物質材料として、水分含有量が充分に低減されてなり、リチウムイオン二次電池の電池特性を有効に向上させるリチウムイオン二次電池用正極活物質複合体を簡易に得ることのできる製造方法を提供することにある。 Therefore, an object of the present invention is to provide a cathode active material for lithium ion secondary batteries that has sufficiently reduced water content and that effectively improves the battery characteristics of lithium ion secondary batteries. An object of the present invention is to provide a manufacturing method that allows a positive electrode active material composite to be easily obtained.
そこで本発明者は、上記課題を解決すべく鋭意検討を行った結果、原料化合物に対し、特定の有機溶媒を特定量で用いて圧縮力及びせん断力を付加しながら混合する等の簡易な方法により、水分含有量が充分に低減されてなるリチウムイオン二次電池用正極活物質複合体を得ることのできる製造方法を見出した。 Therefore, as a result of intensive studies to solve the above problems, the inventors of the present invention have developed a simple method such as mixing raw material compounds while applying compressive force and shear force using a specific amount of a specific organic solvent. As a result, we have discovered a manufacturing method that can produce a positive electrode active material composite for lithium ion secondary batteries in which the water content is sufficiently reduced.
すなわち、本発明は、下記式（Ｉ）又は式（II）：
ＬｉＮｉａＣｏｂＭｎｃＭ１
ｘＯ２・・・（Ｉ）
（式（Ｉ）中、Ｍ１はＭｇ、Ｔｉ、Ｎｂ、Ｆｅ、Ｃｒ、Ｓｉ、Ａｌ、Ｇａ、Ｖ、Ｚｎ、Ｃｕ、Ｓｒ、Ｍｏ、Ｚｒ、Ｓｎ、Ｔａ、Ｗ、Ｌａ、Ｃｅ、Ｐｂ、Ｂｉ及びＧｅから選ばれる１種又は２種以上の元素を示す。ａ、ｂ、ｃ、ｘは、０．３≦ａ＜１、０＜ｂ≦０．７、０＜ｃ≦０．７、０≦ｘ≦０．３、かつ３ａ＋３ｂ＋３ｃ＋（Ｍ１の価数）×ｘ＝３を満たす数を示す。）
ＬｉＮｉｄＣｏｅＡｌｆＭ２
ｙＯ２・・・（II）
（式（II）中、Ｍ２はＭｇ、Ｔｉ、Ｎｂ、Ｆｅ、Ｃｒ、Ｓｉ、Ｇａ、Ｖ、Ｚｎ、Ｃｕ、Ｓｒ、Ｍｏ、Ｚｒ、Ｓｎ、Ｔａ、Ｗ、Ｌａ、Ｃｅ、Ｐｂ、Ｂｉ及びＧｅから選ばれる１種又は２種以上の元素を示す。ｄ、ｅ、ｆ、ｙは、０．４≦ｄ＜１、０＜ｅ≦０．６、０＜ｆ≦０．３、０≦ｙ≦０．３、かつ３ｄ＋３ｅ＋３ｆ＋（Ｍ２の価数）×ｙ＝３を満たす数を示す。）
で表されるリチウム複合酸化物粒子からなる層状型リチウム複合酸化物二次粒子（Ａ）の表面において、下記式（III）又は式（IV）:
ＬｉＣｏｐＭ３
ｚＰＯ４・・・（III）
（式（III）中、Ｍ３はＦｅ、Ｍｎ、Ｍｇ、Ｃａ、Ｓｒ、Ｙ、Ｚｒ、Ｍｏ、Ｂａ、Ｐｂ、Ｂｉ、Ｌａ、Ｃｅ、Ｎｄ又はＧｄを示す。ｐ及びｚは、０．３＜ｐ≦１、０≦ｚ≦０．３、及び２ｐ＋（Ｍ３の価数）×ｚ＝２を満たす数を示す。）
ＬｉＦｅｑＭｎｒＭ４
ｖＰＯ４・・・（IV）
（式（IV）中、Ｍ４はＣｏ、Ｍｇ、Ｃａ、Ｓｒ、Ｙ、Ｚｒ、Ｍｏ、Ｂａ、Ｐｂ、Ｂｉ、Ｌａ、Ｃｅ、Ｎｄ又はＧｄを示す。ｑ、ｒ、及びｖは、０≦ｑ≦１、０≦ｒ≦１、０≦ｖ≦０．３、及びｑ＋ｒ≠０を満たし、かつ２ｑ＋２ｒ＋（Ｍ４の価数）×ｖ＝２を満たす数を示す。）
で表され、表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）と、リチウム複合酸化物粒子とが複合化してなるリチウムイオン二次電池用正極活物質の製造方法であって、次の工程（Ｘ）～（Ｙ）：
（Ｘ）層状型リチウム複合酸化物二次粒子（Ａ）、及び表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）と、リチウム系ポリアニオン粒子（Ｂ）１００質量部に対して３０質量部～３０００質量部である沸点５０℃～１５０℃の有機溶媒（Ｄ）とを配合し、得られた配合スラリーを圧縮力及びせん断力を付加しながら混合して複合化物スラリーを得る工程
（Ｙ）得られた複合化物スラリーを乾燥する工程
を備えるリチウムイオン二次電池用正極活物質複合体の製造方法を提供するものである。
That is, the present invention provides the following formula (I) or formula (II):
LiNi a Co b Mn c M 1 x O 2 ...(I)
(In formula (I), M1 is Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Represents one or more elements selected from Bi and Ge. a, b, c, x are 0.3≦a<1, 0<b≦0.7, 0<c≦0.7, Indicates a number that satisfies 0≦x≦0.3 and 3a+3b+3c+(M valence of 1 )×x=3.)
LiNi d Co e Al f M 2 y O 2 ...(II)
(In formula (II), M2 is Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi and Represents one or more elements selected from Ge. d, e, f, y are 0.4≦d<1, 0<e≦0.6, 0<f≦0.3, 0≦ Indicates a number that satisfies y≦0.3 and 3d+3e+3f+(valence of M2 )×y=3.)
On the surface of layered lithium composite oxide secondary particles (A) consisting of lithium composite oxide particles represented by the following formula (III) or formula (IV):
LiCo p M 3 z PO 4 ...(III)
(In formula (III), M3 represents Fe, Mn, Mg, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. p and z are 0.3 <Indicates a number that satisfies p≦1, 0≦z≦0.3, and 2p+(valence of M3 )×z=2.)
LiFe q Mn r M 4 v PO 4 ...(IV)
(In formula (IV), M 4 represents Co, Mg, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. q, r, and v are 0≦ Indicates a number that satisfies q≦1, 0≦r≦1, 0≦v≦0.3, and q+r≠0, and 2q+2r+(valence of M4 )×v=2.)
A method for producing a positive electrode active material for a lithium ion secondary battery comprising a composite of lithium-based polyanion particles (B) represented by the following and carbon (c) supported on the surface and lithium composite oxide particles, , the following steps (X) to (Y):
(X) Layered lithium composite oxide secondary particles (A), lithium-based polyanion particles (B) with carbon (c) supported on the surface, and 100 parts by mass of the lithium-based polyanion particles (B) A step of blending 30 parts by mass to 3000 parts by mass of an organic solvent (D) with a boiling point of 50°C to 150°C and mixing the resulting blended slurry while applying compressive force and shearing force to obtain a composite slurry. (Y) A method for producing a positive electrode active material composite for a lithium ion secondary battery is provided, which includes a step of drying the obtained composite slurry.
本発明の製造方法によれば、水分含有量が充分に低減されてなり、リチウムイオン二次電池の電池特性を有効に向上させることが可能なリチウムイオン二次電池用正極活物質複合体を簡易な方法により得ることができ、工業的にも有用性の高い製造方法である。 According to the manufacturing method of the present invention, a positive electrode active material composite for a lithium ion secondary battery, which has a sufficiently reduced water content and can effectively improve the battery characteristics of a lithium ion secondary battery, can be easily produced. This production method is highly useful industrially.
以下、本発明について詳細に説明する。 The present invention will be explained in detail below.
本発明のリチウムイオン二次電池用正極活物質複合体の製造方法は、上記式（Ｉ）又は式（II）で表されるリチウム複合酸化物粒子からなる層状型リチウム複合酸化物二次粒子（Ａ）の表面において、上記式（III）又は式（IV）で表され、表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）と、リチウム複合酸化物粒子とが複合化してなるリチウムイオン二次電池用正極活物質複合体を得るための製造方法である。
かかるリチウムイオン二次電池用正極活物質複合体は、層状型リチウム複合酸化物二次粒子（Ａ）の表面において、上記式（Ｉ）又は式（II）で表されるリチウム複合酸化物粒子である一次粒子とリチウム系ポリアニオン粒子（Ｂ）とが複合化してなるか、或いはリチウム複合酸化物粒子である一次粒子が凝集してなる層状型リチウム複合酸化物二次粒子（Ａ）の一部と直接複合化してなり、かつリチウム系ポリアニオン粒子（Ｂ）の表面には炭素（ｃ）が担持してなる。すなわち、かかるリチウムイオン二次電池用正極活物質複合体は、層状型リチウム複合酸化物二次粒子（Ａ）の表面を覆うように、リチウム系ポリアニオン粒子（Ｂ）とリチウム複合酸化物粒子とが強固に複合化しつつ、リチウム系ポリアニオン粒子（Ｂ）の表面を密に覆うように担持されてなる炭素（ｃ）が、層状型リチウム複合酸化物二次粒子（Ａ）とリチウム系ポリアニオン粒子（Ｂ）の間隙に介在してなる構造を有しており、層状型リチウム複合酸化物二次粒子（Ａ）とリチウム系ポリアニオン粒子（Ｂ）との不要な剥離を有効に抑制しながら電池特性を効果的に高めることのできる複合体である。本発明の製造方法であれば、簡易な方法でありながら、かかるリチウムイオン二次電池用正極活物質複合体の水分含有量をも効果的に低減することができるため、工業的にも有用性の高い製造方法である。
The method for producing a positive electrode active material composite for a lithium ion secondary battery of the present invention includes layered lithium composite oxide secondary particles ( On the surface of A), lithium-based polyanion particles (B) represented by the above formula (III) or formula (IV) and having carbon (c) supported on the surface and lithium composite oxide particles are composited. This is a manufacturing method for obtaining a positive electrode active material composite for a lithium ion secondary battery.
Such a positive electrode active material composite for a lithium ion secondary battery has lithium composite oxide particles represented by the above formula (I) or formula (II) on the surface of the layered lithium composite oxide secondary particles (A). Some of the layered lithium composite oxide secondary particles (A) are formed by a composite of certain primary particles and lithium-based polyanion particles (B), or are formed by agglomeration of primary particles that are lithium composite oxide particles. It is directly composited, and carbon (c) is supported on the surface of the lithium-based polyanion particles (B). That is, in such a positive electrode active material composite for a lithium ion secondary battery, the lithium-based polyanion particles (B) and the lithium composite oxide particles cover the surface of the layered lithium composite oxide secondary particles (A). Carbon (c), which is strongly composited and supported so as to densely cover the surface of the lithium-based polyanion particles (B), forms a composite between the layered lithium composite oxide secondary particles (A) and the lithium-based polyanion particles (B). ), which effectively suppresses unnecessary separation between the layered lithium composite oxide secondary particles (A) and the lithium-based polyanion particles (B) while improving battery characteristics. It is a complex that can be used to increase Although the manufacturing method of the present invention is a simple method, it is possible to effectively reduce the water content of the positive electrode active material composite for lithium ion secondary batteries, so it is industrially useful. This is a highly efficient manufacturing method.
本発明のリチウムイオン二次電池用正極活物質複合体の製造方法は、具体的には、次の工程（Ｘ）～（Ｙ）：
（Ｘ）層状型リチウム複合酸化物二次粒子（Ａ）、及び表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）と、リチウム系ポリアニオン粒子（Ｂ）１００質量部に対して３０質量部～３０００質量部である沸点５０℃～１５０℃の有機溶媒（Ｄ）とを配合し、得られた配合スラリーを圧縮力及びせん断力を付加しながら混合して複合化物スラリーを得る工程
（Ｙ）得られた複合化物スラリーを乾燥する工程
を備える。すなわち、いわゆる湿式法による機械的処理によって、リチウムイオン二次電池用正極活物質材料としてのリチウムイオン二次電池用正極活物質複合体を得る方法である。本発明の製造方法であれば、層状型リチウム複合酸化物二次粒子（Ａ）や炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）等の所定の原料粒子を配合してから最終生成物を得るまでの間、すなわち工程（Ｘ）を経て工程（Ｙ）を経るまでの工程中において、生成物が不要に水分を吸着してしまうことを懸念する必要がなく、また上記原料粒子の劣化を助長することなく、有効かつ効率的にリチウムイオン二次電池用正極活物質複合体を得ることができる。
Specifically, the method for producing a positive electrode active material composite for a lithium ion secondary battery of the present invention includes the following steps (X) to (Y):
(X) Layered lithium composite oxide secondary particles (A), lithium-based polyanion particles (B) with carbon (c) supported on the surface, and 100 parts by mass of the lithium-based polyanion particles (B) A step of blending 30 parts by mass to 3000 parts by mass of an organic solvent (D) with a boiling point of 50°C to 150°C and mixing the resulting blended slurry while applying compressive force and shearing force to obtain a composite slurry. (Y) A step of drying the obtained composite slurry is provided. That is, it is a method of obtaining a positive electrode active material composite for a lithium ion secondary battery as a positive electrode active material material for a lithium ion secondary battery by mechanical treatment using a so-called wet method. In the production method of the present invention, predetermined raw material particles such as layered lithium composite oxide secondary particles (A) and lithium-based polyanion particles (B) supported by carbon (c) are blended, and then the final Until the product is obtained, that is, during the process from step (X) to step (Y), there is no need to worry about the product unnecessarily adsorbing moisture, and the above-mentioned raw material particles A positive electrode active material composite for a lithium ion secondary battery can be obtained effectively and efficiently without promoting deterioration of the lithium ion secondary battery.
工程（Ｘ）は、層状型リチウム複合酸化物二次粒子（Ａ）、及び表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）と、リチウム系ポリアニオン粒子（Ｂ）１００質量部に対して３０質量部～３０００質量部である沸点５０℃～１５０℃の有機溶媒（Ｄ）とを配合し、得られた配合スラリーを圧縮力及びせん断力を付加しながら混合して複合化物スラリーを得る工程である。 Step (X) includes layered lithium composite oxide secondary particles (A), lithium-based polyanion particles (B) having carbon (c) supported on their surfaces, and 100 parts by mass of the lithium-based polyanion particles (B). 30 parts by mass to 3000 parts by mass of an organic solvent (D) with a boiling point of 50°C to 150°C, and the resulting blended slurry is mixed while applying compressive force and shear force to form a composite slurry. This is the process of obtaining
工程（Ｘ）において用いる層状型リチウム複合酸化物二次粒子（Ａ）は、下記式（Ｉ）又は式（II）で表される。
ＬｉＮｉａＣｏｂＭｎｃＭ１
ｘＯ２・・・（Ｉ）
（式（Ｉ）中、Ｍ１はＭｇ、Ｔｉ、Ｎｂ、Ｆｅ、Ｃｒ、Ｓｉ、Ａｌ、Ｇａ、Ｖ、Ｚｎ、Ｃｕ、Ｓｒ、Ｍｏ、Ｚｒ、Ｓｎ、Ｔａ、Ｗ、Ｌａ、Ｃｅ、Ｐｂ、Ｂｉ及びＧｅから選ばれる１種又は２種以上の元素を示す。ａ、ｂ、ｃ、ｘは、０．３≦ａ＜１、０＜ｂ≦０．７、０＜ｃ≦０．７、０≦ｘ≦０．３、かつ３ａ＋３ｂ＋３ｃ＋（Ｍ１の価数）×ｘ＝３を満たす数を示す。）
ＬｉＮｉｄＣｏｅＡｌｆＭ２
ｙＯ２・・・（II）
（式（II）中、Ｍ２はＭｇ、Ｔｉ、Ｎｂ、Ｆｅ、Ｃｒ、Ｓｉ、Ｇａ、Ｖ、Ｚｎ、Ｃｕ、Ｓｒ、Ｍｏ、Ｚｒ、Ｓｎ、Ｔａ、Ｗ、Ｌａ、Ｃｅ、Ｐｂ、Ｂｉ及びＧｅから選ばれる１種又は２種以上の元素を示す。ｄ、ｅ、ｆ、ｙは、０．４≦ｄ＜１、０＜ｅ≦０．６、０＜ｆ≦０．３、０≦ｙ≦０．３、かつ３ｄ＋３ｅ＋３ｆ＋（Ｍ２の価数）×ｙ＝３を満たす数を示す。）
The layered lithium composite oxide secondary particles (A) used in step (X) are represented by the following formula (I) or formula (II).
LiNi a Co b Mn c M 1 x O 2 ...(I)
(In formula (I), M1 is Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Represents one or more elements selected from Bi and Ge. a, b, c, x are 0.3≦a<1, 0<b≦0.7, 0<c≦0.7, Indicates a number that satisfies 0≦x≦0.3 and 3a+3b+3c+(M valence of 1 )×x=3.)
LiNi d Co e Al f M 2 y O 2 ...(II)
(In formula (II), M2 is Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi and Represents one or more elements selected from Ge. d, e, f, y are 0.4≦d<1, 0<e≦0.6, 0<f≦0.3, 0≦ Indicates a number that satisfies y≦0.3 and 3d+3e+3f+(valence of M2 )×y=3.)
上記式（Ｉ）で表されるリチウムニッケル複合酸化物（いわゆるＬｉ－Ｎｉ－Ｃｏ－Ｍｎ酸化物であり、以後「ＮＣＭ系複合酸化物」とも称する。）粒子、並びに上記式（II）で表されるリチウムニッケル複合酸化物（いわゆるＬｉ－Ｎｉ－Ｃｏ－Ａｌ酸化物であり、以後「ＮＣＡ系複合酸化物」とも称する。）粒子は、いずれも層状岩塩構造を有する粒子である。
これらの粒子は、一次粒子が凝集することによって形成される。したがって、かかる層状型リチウム複合酸化物二次粒子（Ａ）についても、同様に「ＮＣＭ系複合酸化物二次粒子（Ａ）」、「ＮＣＡ系複合酸化物二次粒子（Ａ）」とも称する。
Lithium-nickel composite oxide (so-called Li-Ni-Co-Mn oxide, hereinafter also referred to as "NCM composite oxide") particles represented by the above formula (I), and particles represented by the above formula (II). All of the lithium-nickel composite oxide (so-called Li-Ni-Co-Al oxide, hereinafter also referred to as "NCA-based composite oxide") particles have a layered rock salt structure.
These particles are formed by agglomeration of primary particles. Therefore, such layered lithium composite oxide secondary particles (A) are also referred to as "NCM composite oxide secondary particles (A)" and "NCA composite oxide secondary particles (A)."
上記式（Ｉ）中のＭ１は、Ｍｇ、Ｔｉ、Ｎｂ、Ｆｅ、Ｃｒ、Ｓｉ、Ａｌ、Ｇａ、Ｖ、Ｚｎ、Ｃｕ、Ｓｒ、Ｍｏ、Ｚｒ、Ｓｎ、Ｔａ、Ｗ、Ｌａ、Ｃｅ、Ｐｂ、Ｂｉ及びＧｅから選ばれる１種又は２種以上の元素を示す。
また、上記式（Ｉ）中のａ、ｂ、ｃ、ｘは、０．３≦ａ＜１、０＜ｂ≦０．７、０＜ｃ≦０．７、０≦ｘ≦０．３、かつ３ａ＋３ｂ＋３ｃ＋（Ｍ１の価数）×ｘ＝３を満たす数である。
M 1 in the above formula (I) is Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb , Bi, and Ge.
In addition, a, b, c, and x in the above formula (I) are 0.3≦a<1, 0<b≦0.7, 0<c≦0.7, 0≦x≦0.3, And it is a number that satisfies 3a+3b+3c+(valence of M1 )×x=3.
上記ＮＣＭ系複合酸化物二次粒子（Ａ）において、Ｎｉ、Ｃｏ及びＭｎは、電子伝導性に優れ、電池容量及び出力特性に寄与することが知られている。また、サイクル特性の観点からは、かかる遷移元素の一部が他の金属元素Ｍ１により置換されていることが好ましい。 In the NCM-based composite oxide secondary particles (A), Ni, Co, and Mn are known to have excellent electronic conductivity and contribute to battery capacity and output characteristics. Further, from the viewpoint of cycle characteristics, it is preferable that a part of the transition element is replaced by another metal element M1 .
上記ＮＣＭ系複合酸化物二次粒子（Ａ）としては、具体的には、例えばＬｉＮｉ0.33Ｃｏ0.33 Ｍｎ0.34Ｏ2、ＬｉＮｉ0.8Ｃｏ0.1Ｍｎ 0.1Ｏ2、ＬｉＮｉ0.6Ｃｏ0.2Ｍｎ 0.2Ｏ2、ＬｉＮｉ0.33Ｃｏ0.31Ｍｎ0.33Ｍｇ0.045Ｏ2、又はＬｉＮｉ0.33Ｃｏ0.31Ｍｎ0.33Ｚｎ0.045Ｏ2等が挙げられる。なかでも、放電容量を重視する場合には、ＬｉＮｉ0.8Ｃｏ0.1Ｍｎ 0.1Ｏ2、ＬｉＮｉ0.6Ｃｏ0.2Ｍｎ 0.2Ｏ2等のＮｉ量の多い組成からなる粒子が好ましく、サイクル特性を重視する場合には、ＬｉＮｉ0.33Ｃｏ0.33 Ｍｎ0.34Ｏ2、ＬｉＮｉ0.33Ｃｏ0.31Ｍｎ0.33Ｍｇ0.045Ｏ2等のＮｉ量の少ない組成からなる粒子が好ましい。 Specifically, the NCM-based composite oxide secondary particles (A) include, for example, LiNi 0.33 Co 0.33 Mn 0.34 O 2 , LiNi 0.8 Co 0.1 Mn 0.1 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2 , LiNi 0.33 Examples include Co 0.31 Mn 0.33 Mg 0.045 O 2 or LiNi 0.33 Co 0.31 Mn 0.33 Zn 0.045 O 2 . Among these, particles having a composition with a large amount of Ni such as LiNi 0.8 Co 0.1 Mn 0.1 O 2 and LiNi 0.6 Co 0.2 Mn 0.2 O 2 are preferable when emphasis is placed on discharge capacity, and when emphasis is placed on cycle characteristics. , LiNi 0.33 Co 0.33 Mn 0.34 O 2 , LiNi 0.33 Co 0.31 Mn 0.33 Mg 0.045 O 2 and the like are preferred.
上記式（II）中のＭ２は、Ｍｇ、Ｔｉ、Ｎｂ、Ｆｅ、Ｃｒ、Ｓｉ、Ｇａ、Ｖ、Ｚｎ、Ｃｕ、Ｓｒ、Ｍｏ、Ｚｒ、Ｓｎ、Ｔａ、Ｗ、Ｌａ、Ｃｅ、Ｐｂ、Ｂｉ及びＧｅから選ばれる１種又は２種以上の元素を示す。
また、上記式（II）中のｄ、ｅ、ｆ、ｙは、０．４≦ｄ＜１、０＜ｅ≦０．６、０＜ｆ≦０．３、０≦ｙ≦０．３、かつ３ｄ＋３ｅ＋３ｆ＋（Ｍ２の価数）×ｙ＝３を満たす数である。
M2 in the above formula (II) is Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi and Ge.
In addition, d, e, f, and y in the above formula (II) are 0.4≦d<1, 0<e≦0.6, 0<f≦0.3, 0≦y≦0.3, And it is a number that satisfies 3d+3e+3f+(valence of M2 )×y=3.
上記ＮＣＡ系複合酸化物二次粒子（Ａ）は、式（Ｉ）で表されるＮＣＭ系複合酸化物粒子よりも、さらに電池容量及び出力特性に優れている。加えて、Ａｌの含有により、雰囲気中の湿分による変質も生じ難く、安全性にも優れている。
上記ＮＣＡ系複合酸化物二次粒子（Ａ）としては、具体的には、例えばＬｉＮｉ0.8Ｃｏ0.1Ａｌ0.1Ｏ2、ＬｉＮｉ0.8Ｃｏ0.15Ａｌ0.03Ｍｇ0.03Ｏ2、ＬｉＮｉ0.8Ｃｏ0.15Ａｌ0.03Ｚｎ0.03Ｏ2等からなる粒子が挙げられる。なかでもＬｉＮｉ0.8Ｃｏ0.15Ａｌ0.03Ｍｇ0.03Ｏ2からなる粒子が好ましい。
The NCA-based composite oxide secondary particles (A) have even better battery capacity and output characteristics than the NCM-based composite oxide particles represented by formula (I). In addition, due to the Al content, deterioration due to moisture in the atmosphere is less likely to occur, and it is also excellent in safety.
As for the above NCA -based composite oxide secondary particles (a), for example, Lini 0.8 CO 0.1 AL 0.1 O 2 , LINI 0.8 CO 0.03 MG 0.03 O2 , Lini 0.8 CO 0.15 AL 0.03 ZN 0.03 Examples include particles consisting of 2 etc. Among these, particles made of LiNi 0.8 Co 0.15 Al 0.03 Mg 0.03 O 2 are preferred.
層状型リチウム複合酸化物二次粒子（Ａ）の一次粒子としての平均粒径は、好ましくは５００ｎｍ以下であり、より好ましくは３００ｎｍ以下である。また、上記一次粒子の平均粒径の下限値は特に限定されないが、ハンドリングの観点から、５０ｎｍ以上が好ましい。
ここで、平均粒径とは、ＳＥＭ又はＴＥＭの電子顕微鏡による観察において、数十個の粒子の粒径（長軸の長さ）の測定値の平均値を意味し、以後の説明においても同義である。
The average particle size of the layered lithium composite oxide secondary particles (A) as primary particles is preferably 500 nm or less, more preferably 300 nm or less. Further, the lower limit of the average particle diameter of the primary particles is not particularly limited, but from the viewpoint of handling, it is preferably 50 nm or more.
Here, the average particle size means the average value of the measured values of the particle size (long axis length) of several dozen particles in observation using an SEM or TEM electron microscope, and has the same meaning in the following explanation. It is.
また、上記一次粒子が凝集して形成する層状型リチウム複合酸化物二次粒子（Ａ）の平均粒径は、好ましくは２５μｍ以下であり、より好ましくは２０μｍ以下である。また、上記二次粒子の平均粒径の下限値は特に限定されないが、ハンドリングの観点から１μｍ以上が好ましく、５μｍ以上がより好ましい。 Further, the average particle size of the layered lithium composite oxide secondary particles (A) formed by agglomeration of the primary particles is preferably 25 μm or less, more preferably 20 μm or less. Further, the lower limit of the average particle diameter of the secondary particles is not particularly limited, but from the viewpoint of handling, it is preferably 1 μm or more, and more preferably 5 μm or more.
層状型リチウム複合酸化物二次粒子（Ａ）を製造するには、例えば、
リチウム化合物、ニッケル化合物、コバルト化合物、及びマンガン化合物を含有する混合粉体を焼成して、ＮＣＭ系複合酸化物二次粒子（Ａ）を得るか（製法ａ１）、或いは
リチウム化合物、ニッケル化合物、コバルト化合物、及びアルミニウム化合物を含有する混合粉体を焼成して、ＮＣＡ系複合酸化物二次粒子（Ａ）を得ればよい（製法ａ２）。
To produce the layered lithium composite oxide secondary particles (A), for example,
Either a mixed powder containing a lithium compound, a nickel compound, a cobalt compound, and a manganese compound is calcined to obtain NCM-based composite oxide secondary particles (A) (manufacturing method a1), or a lithium compound, a nickel compound, and a cobalt compound are obtained. The mixed powder containing the compound and the aluminum compound may be fired to obtain the NCA-based composite oxide secondary particles (A) (manufacturing method a2).
具体的には、製法ａ１の場合、まず原料化合物、例えば、ニッケル化合物、コバルト化合物、及びマンガン化合物を、所望する複合酸化物の組成となるように水に溶解させて水溶液ａを得る。
次に、上記水溶液ａに、水酸化ナトリウムや水酸化カリウム等のアルカリ剤を添加して水溶液ｂとし、溶解している金属成分を中和反応によって共沈させ、金属複合水酸化物を得る。次いで水溶液ｂを３０℃～６０℃の温度で３０分間～１２０分間撹拌して、金属複合水酸化物を生成させる。
Specifically, in the case of production method a1, raw material compounds, for example, a nickel compound, a cobalt compound, and a manganese compound, are first dissolved in water to obtain a desired composite oxide composition to obtain an aqueous solution a.
Next, an alkali agent such as sodium hydroxide or potassium hydroxide is added to the aqueous solution a to obtain an aqueous solution b, and the dissolved metal components are co-precipitated by a neutralization reaction to obtain a metal composite hydroxide. Next, the aqueous solution b is stirred at a temperature of 30° C. to 60° C. for 30 minutes to 120 minutes to produce a metal composite hydroxide.
撹拌後、水溶液ｂを濾過して金属複合水酸化物を回収し、水で洗浄後、乾燥するのが好ましい。
次いで、所望する複合酸化物の組成となるように、上記金属複合水酸化物とリチウム化合物を乾式混合し、酸素雰囲気下で焼成することにより、ＮＣＭ系複合酸化物を得る。
最後に、得られた焼成物を水洗した後、濾過、及び乾燥してＮＣＭ系複合酸化物粒子（Ａ）を得る。
After stirring, the aqueous solution b is preferably filtered to recover the metal composite hydroxide, washed with water, and then dried.
Next, the metal composite hydroxide and the lithium compound are dry mixed to obtain a desired composite oxide composition, and the mixture is fired in an oxygen atmosphere to obtain an NCM-based composite oxide.
Finally, the obtained fired product is washed with water, filtered, and dried to obtain NCM-based composite oxide particles (A).
なお、製法ａ２の場合、原料化合物としてリチウム化合物、ニッケル化合物、コバルト化合物、及びアルミニウム化合物を用いる以外、製法ａ１と同様にしてＮＣＡ系複合酸化物二次粒子（Ａ）を得ることができる。 In the case of production method a2, the NCA-based composite oxide secondary particles (A) can be obtained in the same manner as production method a1, except that a lithium compound, a nickel compound, a cobalt compound, and an aluminum compound are used as raw material compounds.
工程（Ｘ）において用いるリチウム複合酸化物二次粒子（Ａ）の表面において、リチウム複合酸化物粒子と複合化されてなる、リチウム系ポリアニオン粒子（Ｂ）は、下記式（III）又は式（IV）で表される。
ＬｉＣｏｐＭ３
ｚＰＯ４・・・（III）
（式（III）中、Ｍ３はＦｅ、Ｍｎ、Ｍｇ、Ｃａ、Ｓｒ、Ｙ、Ｚｒ、Ｍｏ、Ｂａ、Ｐｂ、Ｂｉ、Ｌａ、Ｃｅ、Ｎｄ又はＧｄを示す。ｐ及びｚは、０．３＜ｐ≦１、０≦ｚ≦０．３、及び２ｐ＋（Ｍ３の価数）×ｚ＝２を満たす数を示す。）
ＬｉＦｅｑＭｎｒＭ４
ｖＰＯ４・・・（IV）
（式（IV）中、Ｍ４はＣｏ、Ｍｇ、Ｃａ、Ｓｒ、Ｙ、Ｚｒ、Ｍｏ、Ｂａ、Ｐｂ、Ｂｉ、Ｌａ、Ｃｅ、Ｎｄ又はＧｄを示す。ｑ、ｒ、及びｖは、０≦ｑ≦１、０≦ｒ≦１、０≦ｖ≦０．３、及びｑ＋ｒ≠０を満たし、かつ２ｑ＋２ｒ＋（Ｍ４の価数）×ｖ＝２を満たす数を示す。）
すなわち、式（III）で表されるリチウム系ポリアニオン粒子（Ｂ）は、Ｃｏ単独で、又はＣｏと1種以上の金属（Ｍ）を含み、式（IV）で表されるリチウム系ポリアニオン粒子（Ｂ）は、Ｆｅ又はＭｎの少なくともいずれか一方の遷移金属を含む。そして、これら式（III）で表されるリチウム系ポリアニオン粒子（Ｂ）、及び式（IV）で表されるリチウム系ポリアニオン粒子（Ｂ）は、いずれもオリビン型構造を有し、良好なリチウムイオン伝導性をもたらし得る化合物である。
On the surface of the lithium composite oxide secondary particles (A) used in step (X), the lithium-based polyanion particles (B) composited with the lithium composite oxide particles have the following formula (III) or formula (IV ).
LiCo p M 3 z PO 4 ...(III)
(In formula (III), M3 represents Fe, Mn, Mg, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. p and z are 0.3 <Indicates a number that satisfies p≦1, 0≦z≦0.3, and 2p+(valence of M3 )×z=2.)
LiFe q Mn r M 4 v PO 4 ...(IV)
(In formula (IV), M 4 represents Co, Mg, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. q, r, and v are 0≦ Indicates a number that satisfies q≦1, 0≦r≦1, 0≦v≦0.3, and q+r≠0, and 2q+2r+(valence of M4 )×v=2.)
That is, the lithium-based polyanion particles (B) represented by the formula (III) contain Co alone or Co and one or more metals (M), and the lithium-based polyanion particles (B) represented by the formula (IV) B) contains at least one transition metal of Fe or Mn. The lithium-based polyanion particles (B) represented by the formula (III) and the lithium-based polyanion particles (B) represented by the formula (IV) both have an olivine structure and are good lithium ion particles. It is a compound that can provide conductivity.
上記式（III）で表されるリチウム系ポリアニオン粒子（Ｂ）としては、二次電池用正極活物質の平均放電電圧の観点から０．３≦ｐ≦１が好ましく、０．４≦ｐ≦１がより好ましく、０．５≦ｐ≦１がさらに好ましい。具体的には、例えばＬｉＣｏＰＯ４、ＬｉＣｏ０．９Ｍｎ０．１ＰＯ４、ＬｉＣｏ０．8Ｍｎ０．2ＰＯ４、ＬｉＣｏ０．７Ｍｎ０．3ＰＯ４、ＬｉＣｏ０．９Ｆｅ０．１ＰＯ４、ＬｉＣｏ０．8Ｆｅ０．2ＰＯ４、ＬｉＣｏ０．7Ｆｅ０．3ＰＯ４、ＬｉＣｏ０．8Ｍｎ０．1Ｆｅ０．1ＰＯ４が挙げられ、なかでもＬｉＣｏＰＯ４、ＬｉＣｏ０．8Ｍｎ０．2ＰＯ４、ＬｉＣｏ０．8Ｆｅ０．2ＰＯ４、ＬｉＣｏ０．8Ｍｎ０．1Ｆｅ０．1ＰＯ４が好ましい。 The lithium-based polyanion particles (B) represented by the above formula (III) are preferably 0.3≦p≦1 from the viewpoint of the average discharge voltage of the positive electrode active material for secondary batteries, and 0.4≦p≦1. is more preferable, and even more preferably 0.5≦p≦1. Specifically , for example , LiCoPO4 , LiCo0.9Mn0.1PO4 , LiCo0.8Mn0.2PO4 , LiCo0.7Mn0.3PO4 , LiCo0.9Fe0.1 PO4 , LiCo0.8 Fe0.2 PO4 , LiCo0.7 Fe0.3 PO4 , LiCo0.8 Mn0.1 Fe0.1 PO4 , among which LiCoPO4 , LiCo0 .8 Mn 0.2 PO 4 , LiCo 0.8 Fe 0.2 PO 4 and LiCo 0.8 Mn 0.1 Fe 0.1 PO 4 are preferred.
上記式（IV）で表されるリチウム系ポリアニオン粒子（Ｂ）としては、二次電池用正極活物質の平均放電電圧の観点から、０．５≦ｒ≦１が好ましく、０．６≦ｒ≦１がより好ましく、０．６５≦ｒ≦１がさらに好ましい。具体的には、例えばＬｉＭｎＰＯ４、ＬｉＦｅ0.1Ｍｎ0.9ＰＯ４、ＬｉＦｅ0.2Ｍｎ0.8ＰＯ４、ＬｉＦｅ0.15Ｍｎ0.75Ｍｇ0.1ＰＯ４、ＬｉＦｅ0.19Ｍｎ0.75Ｚｒ0.03ＰＯ４、ＬｉＦｅ0.3Ｍｎ0.7ＰＯ４、ＬｉＦｅ0.4Ｍｎ0.6ＰＯ４、ＬｉＦｅ0.5Ｍｎ0.5ＰＯ４等が挙げられ、なかでもＬｉＦｅ0.3Ｍｎ0.7ＰＯ４、ＬｉＦｅ0.2Ｍｎ0.8ＰＯ４が好ましい。 The lithium-based polyanion particles (B) represented by the above formula (IV) are preferably 0.5≦r≦1, and 0.6≦r≦ from the viewpoint of the average discharge voltage of the positive electrode active material for secondary batteries. 1 is more preferable, and 0.65≦r≦1 is even more preferable. Specifically, for example, LiMnPO 4 , LiFe 0.1 Mn 0.9 PO 4 , LiFe 0.2 Mn 0.8 PO 4 , LiFe 0.15 Mn 0.75 Mg 0.1 PO 4 , LiFe 0.19 Mn 0.75 Zr 0.03 PO 4 , LiFe 0.3 Mn 0.7 PO 4 , LiFe 0.4 Examples include Mn 0.6 PO 4 , LiFe 0.5 Mn 0.5 PO 4 , and among them, LiFe 0.3 Mn 0.7 PO 4 and LiFe 0.2 Mn 0.8 PO 4 are preferred.
リチウム系ポリアニオン粒子（Ｂ）の平均粒径は、これを用いて得られる正極が良好な体積エネルギー密度を発現する観点から、好ましくは２０ｎｍ～２００ｎｍであり、より好ましくは３０ｎｍ～１５０ｎｍである。 The average particle size of the lithium-based polyanion particles (B) is preferably 20 nm to 200 nm, more preferably 30 nm to 150 nm, from the viewpoint that the positive electrode obtained using the particles exhibits good volume energy density.
リチウム系ポリアニオン粒子（Ｂ）の２５℃での２０ＭＰａ加圧時におけるリチウムイオン伝導度は、１×１０－７Ｓ／ｃｍ以上であることが好ましく、１×１０－６Ｓ／ｃｍ以上であることがより好ましい。リチウム系ポリアニオン粒子（Ｂ）のリチウムイオン伝導度の上限値は特に限定されない。 The lithium ion conductivity of the lithium-based polyanion particles (B) when pressurized at 20 MPa at 25° C. is preferably 1×10 −7 S/cm or more, and preferably 1×10 −6 S/cm or more. is more preferable. The upper limit of the lithium ion conductivity of the lithium-based polyanion particles (B) is not particularly limited.
上記リチウム系ポリアニオン粒子（Ｂ）は、その表面に炭素（ｃ）が担持されてなる。かかる炭素（ｃ）の炭素源としては、セルロースナノファイバー、又は水溶性炭素材料が挙げられる。 The lithium-based polyanion particles (B) have carbon (c) supported on their surfaces. Examples of the carbon source of carbon (c) include cellulose nanofibers and water-soluble carbon materials.
炭素（ｃ）の炭素源となり得るセルロースナノファイバーとは、全ての植物細胞壁の約５割を占める骨格成分であって、かかる細胞壁を構成する植物繊維をナノサイズまで解繊等することにより得ることができる軽量高強度繊維であり、セルロースナノファイバー由来の炭素は、周期的構造を有する。かかるセルロースナノファイバーの繊維径は、１ｎｍ～１００ｎｍであり、水への良好な分散性も有している。リチウム系ポリアニオン粒子（Ｂ）の表面に堅固に担持されて、リチウム系ポリアニオン粒子（Ｂ）に電子伝導性を付与し、有用なリチウムイオン二次電池用正極活物質複合体を得ることができる。 Cellulose nanofibers, which can be a source of carbon (c), are skeletal components that account for about 50% of all plant cell walls, and can be obtained by fibrillating plant fibers that make up such cell walls to nano-size. The carbon derived from cellulose nanofibers has a periodic structure. The fiber diameter of such cellulose nanofibers is 1 nm to 100 nm, and they also have good dispersibility in water. It is firmly supported on the surface of the lithium-based polyanion particles (B), imparting electronic conductivity to the lithium-based polyanion particles (B), and a useful positive electrode active material composite for lithium ion secondary batteries can be obtained.
炭素（ｃ）の炭素源となり得る水溶性炭素材料とは、２５℃の水１００ｇに、水溶性炭素材料の炭素原子換算量で０．４ｇ以上、好ましくは１．０ｇ以上溶解する炭素材料を意味し、炭化されることで炭素として上記リチウム系ポリアニオン粒子（Ｂ）の表面に存在することとなる。かかる水溶性炭素材料としては、例えば、糖類、ポリオール、ポリエーテル、及び有機酸から選ばれる１種又は２種以上が挙げられる。より具体的には、例えば、グルコース、フルクトース、ガラクトース、マンノース等の単糖類；マルトース、スクロース、セロビオース等の二糖類；デンプン、デキストリン等の多糖類；エチレングリコール、プロピレングリコール、ジエチレングリコール、ポリエチレングリコール、ブタンジオール、プロパンジオール、ポリビニルアルコール、グリセリン等のポリオールやポリエーテル；クエン酸、酒石酸、アスコルビン酸等の有機酸が挙げられる。なかでも、溶媒への溶解性及び分散性を高めて炭素材料として効果的に機能させる観点から、グルコース、フルクトース、スクロース、デキストリンが好ましく、グルコースがより好ましい。 A water-soluble carbon material that can be a carbon source for carbon (c) means a carbon material that dissolves in 100 g of water at 25 ° C. in terms of carbon atom equivalent of 0.4 g or more, preferably 1.0 g or more. However, by being carbonized, it exists as carbon on the surface of the lithium-based polyanion particles (B). Examples of such water-soluble carbon materials include one or more selected from saccharides, polyols, polyethers, and organic acids. More specifically, for example, monosaccharides such as glucose, fructose, galactose, and mannose; disaccharides such as maltose, sucrose, and cellobiose; polysaccharides such as starch and dextrin; ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, and butane. Examples include polyols and polyethers such as diol, propanediol, polyvinyl alcohol, and glycerin; and organic acids such as citric acid, tartaric acid, and ascorbic acid. Among these, glucose, fructose, sucrose, and dextrin are preferred, and glucose is more preferred, from the viewpoint of improving solubility and dispersibility in solvents and functioning effectively as a carbon material.
なお、リチウム系ポリアニオン粒子（Ｂ）の表面に存在する炭素（ｃ）、すなわちセルロースナノファイバー由来の炭素又は水溶性炭素材料由来の炭素の原子換算量（炭素の担持量）は、リチウム系ポリアニオン粒子（Ｂ）について炭素・硫黄分析装置を用いて測定した炭素量として、確認することができる。 Note that the atomic equivalent amount (supported amount of carbon) of carbon (c) present on the surface of the lithium-based polyanion particles (B), that is, the carbon derived from cellulose nanofibers or the carbon derived from the water-soluble carbon material, is (B) can be confirmed as the amount of carbon measured using a carbon/sulfur analyzer.
かかる炭素（ｃ）の担持量は、炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）全量１００質量％中に、好ましくは０．１質量％以上５質量％未満であり、より好ましくは０．２質量％～４質量％であり、さらに好ましくは０．３質量％～３質量％である。 The amount of carbon (c) supported is preferably 0.1% by mass or more and less than 5% by mass, more preferably 0.1% by mass or more and less than 5% by mass based on 100% by mass of the lithium-based polyanion particles (B) supported by carbon (c). is 0.2% by mass to 4% by mass, more preferably 0.3% by mass to 3% by mass.
炭素（ｃ）が担持されてなるリチウム系ポリアニオン粒子（Ｂ）を製造するには、まず、
リチウム化合物、少なくともコバルト化合物を含む金属（Ｍ３）化合物（Ｍ３は式（III）と同義である）、並びにリン酸化合物を水熱反応に付すか（製法ｂ１）、或いは
リチウム化合物、少なくとも鉄化合物又はマンガン化合物を含む金属（Ｍ４）化合物（Ｍ４は式（IV）と同義である）、並びにリン酸化合物を水熱反応に付せばよい（製法ｂ２）。すなわち、製法ｂ１又は製法ｂ２のいずれかの方法により、リチウム化合物、所定の金属化合物、並びにリン酸化合物を、いわゆる湿式反応である水熱反応に付して、上記式（III）又は式（IV）で表されるリチウム系ポリアニオン一次粒子を得た後、得られた一次粒子に炭素を担持させればよい。
In order to produce lithium-based polyanion particles (B) on which carbon (c) is supported, first,
A lithium compound, a metal (M 3 ) compound containing at least a cobalt compound (M 3 has the same meaning as formula (III)), and a phosphoric acid compound are subjected to a hydrothermal reaction (manufacturing method b1), or a lithium compound, at least iron A compound or a metal (M 4 ) compound containing a manganese compound (M 4 is synonymous with formula (IV)) and a phosphoric acid compound may be subjected to a hydrothermal reaction (manufacturing method b2). That is, by either production method b1 or production method b2, a lithium compound, a predetermined metal compound, and a phosphoric acid compound are subjected to a hydrothermal reaction, which is a so-called wet reaction, to obtain the above formula (III) or formula (IV). ) After obtaining lithium-based polyanion primary particles represented by the following formula, carbon may be supported on the obtained primary particles.
具体的には、炭素（ｃ）が担持されてなるリチウム系ポリアニオン粒子（Ｂ）を製造する方法の一例として、リチウム化合物、鉄化合物、マンガン化合物及びリン酸化合物を用いて製法ｂ２を採用し、上記式（IV）で示されるリチウム系ポリアニオン粒子（Ｂ）の一次粒子を得た後に炭素（ｃ）を担持させる場合につき、以下に記す。 Specifically, as an example of a method for producing lithium-based polyanion particles (B) on which carbon (c) is supported, production method b2 is adopted using a lithium compound, an iron compound, a manganese compound, and a phosphoric acid compound, The case where carbon (c) is supported after obtaining the primary particles of the lithium-based polyanion particles (B) represented by the above formula (IV) will be described below.
製法ｂ２は、より具体的には、次の工程（ｉ）～（iii）：
（ｉ）リチウム化合物を含む混合物に、リン酸化合物を混合して一次粒子の前駆体を得る工程、及び
（ii）得られた前駆体と、少なくとも鉄化合物及び／又はマンガン化合物を含む金属塩を含有するスラリー水を水熱反応に付して、一次粒子を得る工程
（iii）得られた一次粒子と炭素源を含むスラリーを噴霧乾燥し、得られた造粒物を焼成して、一次粒子の表面に炭素が担持してなる焼成物を得る工程
を備えればよい。
More specifically, manufacturing method b2 includes the following steps (i) to (iii):
(i) mixing a phosphoric acid compound into a mixture containing a lithium compound to obtain a precursor of primary particles; and (ii) mixing the obtained precursor with a metal salt containing at least an iron compound and/or a manganese compound. A step of obtaining primary particles by subjecting the slurry water contained therein to a hydrothermal reaction (iii) Spray drying the slurry containing the obtained primary particles and a carbon source, and firing the obtained granules to obtain primary particles. The method may include a step of obtaining a fired product in which carbon is supported on the surface of the fired product.
工程（ｉ）において、用い得るリチウム化合物としては、水酸化リチウム（例えばＬｉＯＨ、ＬｉＯＨ・Ｈ２Ｏ）、炭酸リチウム、硫酸リチウム、酢酸リチウムが挙げられ、リン酸化合物としては、オルトリン酸（Ｈ３ＰＯ４、リン酸）、メタリン酸、ピロリン酸、三リン酸、四リン酸、リン酸アンモニウム、リン酸水素アンモニウム等が挙げられる。
なかでもリン酸を用い、これを混合物に滴下して少量ずつ加えながら混合するのが好ましく、混合した後に窒素をパージするのが好ましい。また、リン酸化合物を混合した後の混合物中における溶存酸素濃度を０．５ｍｇ／Ｌ以下とするのが好ましい。
In step (i), examples of lithium compounds that can be used include lithium hydroxide (for example, LiOH, LiOH.H 2 O), lithium carbonate, lithium sulfate, and lithium acetate, and examples of phosphoric acid compounds include orthophosphoric acid (H 3 PO 4 , phosphoric acid), metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, ammonium phosphate, ammonium hydrogen phosphate, and the like.
Among these, it is preferable to use phosphoric acid and add it dropwise to the mixture little by little while mixing, and it is preferable to purge with nitrogen after mixing. Moreover, it is preferable that the dissolved oxygen concentration in the mixture after mixing the phosphoric acid compound is 0.5 mg/L or less.
次いで、工程（ii）において、工程（ｉ）で得られた前駆体と、少なくとも鉄化合物及び／又はマンガン化合物を含む金属塩を含有するスラリー水を水熱反応に付す。 Next, in step (ii), the precursor obtained in step (i) and slurry water containing a metal salt containing at least an iron compound and/or a manganese compound are subjected to a hydrothermal reaction.
用い得る鉄化合物としては、酢酸鉄、硝酸鉄、硫酸鉄等が挙げられる。これらは１種単独で用いてもよく、２種以上組み合わせて用いてもよい。
用い得るマンガン化合物としては、酢酸マンガン、硝酸マンガン、硫酸マンガン等が挙げられる。これらは１種単独で用いてもよく、２種以上組み合わせて用いてもよい。
さらに、必要に応じて、金属塩として、鉄化合物及びマンガン化合物以外の金属（Ｍ４）塩を用いてもよい。金属塩におけるＭ１は、上記式（IV）中のＭ４と同義であり、かかる金属塩として、硫酸塩、ハロゲン化合物、有機酸塩、及びこれらの水和物等を用いることができる。これらは１種単独で用いてもよく、２種以上用いてもよい。
Examples of iron compounds that can be used include iron acetate, iron nitrate, iron sulfate, and the like. These may be used alone or in combination of two or more.
Manganese compounds that can be used include manganese acetate, manganese nitrate, manganese sulfate, and the like. These may be used alone or in combination of two or more.
Furthermore, if necessary, metal (M 4 ) salts other than iron compounds and manganese compounds may be used as the metal salt. M 1 in the metal salt has the same meaning as M 4 in the above formula (IV), and as the metal salt, sulfates, halogen compounds, organic acid salts, hydrates thereof, etc. can be used. These may be used alone or in combination of two or more.
水熱反応の温度は、１００℃以上であればよく、１３０℃～１８０℃が好ましく、圧力は０．３ＭＰａ～０．９ＭＰａであるのが好ましく、水熱反応時間は０．１時間～４８時間が好ましい。 The temperature of the hydrothermal reaction may be 100°C or higher, preferably 130°C to 180°C, the pressure is preferably 0.3 MPa to 0.9 MPa, and the hydrothermal reaction time is 0.1 hour to 48 hours. is preferred.
工程（iii）は、上記得られた一次粒子と炭素源を含むスラリーを噴霧乾燥し、得られた造粒物を焼成して、一次粒子の表面に炭素が担持してなる焼成物を得る工程である。かかる炭素源として、上記セルロースナノファイバー又は水溶性炭素材料を用いればよく、これらが焼成されることにより炭化されて、炭素（ｃ）が担持されてなるリチウム系ポリアニオン粒子（Ｂ）を得ることができる。
噴霧乾燥に付するスラリーは、一次粒子、炭素源、及び水を混合すればよく、スラリー中における一次粒子及び炭素源の含有量は、炭素源の炭素原子換算量が、得られる焼成物中に０．１質量％～２０質量％となるような量であるのが望ましい。
Step (iii) is a step of spray-drying the slurry containing the primary particles and carbon source obtained above, and firing the obtained granules to obtain a fired product in which carbon is supported on the surface of the primary particles. It is. As such a carbon source, the above-mentioned cellulose nanofibers or water-soluble carbon materials may be used, and these can be carbonized by firing to obtain lithium-based polyanion particles (B) on which carbon (c) is supported. can.
The slurry to be subjected to spray drying can be prepared by mixing primary particles, a carbon source, and water. The amount is preferably 0.1% by mass to 20% by mass.
噴霧乾燥により得られる造粒物の粒径は、レーザー回折・散乱法に基づく粒度分布におけるＤ50値で、１～２０μｍであるのが好ましい。
得られた造粒物は還元雰囲気又は不活性雰囲気中において焼成するのがよい。焼成条件としては、焼成温度が４００℃～８００℃であり、焼成時間が１０分～３時間であるのが好ましい。
なお、上記式（III）で表される、炭素（ｃ）が担持されてなるリチウム系ポリアニオン粒子（Ｂ）についても、適宜原料化合物を選択しつつ、上記製法に準じて製造すればよい。
The particle size of the granulated product obtained by spray drying is preferably 1 to 20 μm in terms of D 50 value in particle size distribution based on laser diffraction/scattering method.
The obtained granules are preferably fired in a reducing atmosphere or an inert atmosphere. As for the firing conditions, it is preferable that the firing temperature is 400° C. to 800° C. and the firing time is 10 minutes to 3 hours.
Note that the lithium-based polyanion particles (B) on which carbon (c) is supported, represented by the above formula (III), may also be produced according to the above production method while selecting an appropriate raw material compound.
本発明のリチウムイオン二次電池用正極活物質複合体の製造方法が備える工程（Ｘ）では、上記層状型リチウム複合酸化物二次粒子（Ａ）、及び表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）と、リチウム系ポリアニオン粒子（Ｂ）１００質量部に対して３０質量部～３０００質量部である沸点５０℃～１５０℃の有機溶媒（Ｄ）とを配合し、配合スラリーを得る。
このように、本発明では、特定の有機溶媒（Ｄ）を特定量で用いた、いわゆる湿式法を採用することにより、有機溶媒（Ｄ）中に層状型リチウム複合酸化物二次粒子（Ａ）と表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）とが均一に分散し、層状型リチウム複合酸化物二次粒子（Ａ）が中核となりながらリチウム系ポリアニオン粒子（Ｂ）が微細に解砕され、層状型リチウム複合酸化物二次粒子（Ａ）の表面を被覆することができる。また、後に付す配合スラリーを圧縮力及び剪断力を付加しながらの混合処理中や、リチウム複合酸化物二次粒子（Ａ）及びリチウム系ポリアニオン粒子（Ｂ）の投入・配合時、或いはリチウムイオン二次電池用正極活物質複合体の排出時において、過度に大気に接することを有効に防止することができる。これにより、湿式法でありながらも予想外に、工程中において、リチウム複合酸化物二次粒子（Ａ）やリチウム系ポリアニオン粒子（Ｂ）に水分が吸着してしまうのを有効に防止することができる。
In the step (X) of the method for producing a positive electrode active material composite for a lithium ion secondary battery of the present invention, the layered lithium composite oxide secondary particles (A) and carbon (c) supported on the surface thereof are provided. The lithium-based polyanion particles (B) are blended with an organic solvent (D) having a boiling point of 50° C. to 150° C. in an amount of 30 parts by mass to 3000 parts by mass based on 100 parts by mass of the lithium-based polyanion particles (B). Get slurry.
As described above, in the present invention, by employing a so-called wet method using a specific amount of a specific organic solvent (D), layered lithium composite oxide secondary particles (A) are added to the organic solvent (D). and lithium-based polyanion particles (B) having carbon (c) supported on their surfaces are uniformly dispersed, and the lithium-based polyanion particles (B) are formed with the layered lithium composite oxide secondary particles (A) serving as the core. It can be finely crushed and coat the surface of the layered lithium composite oxide secondary particles (A). In addition, during the mixing process while applying compressive force and shear force to the blended slurry to be added later, when adding and blending the lithium composite oxide secondary particles (A) and the lithium-based polyanion particles (B), or when lithium ion secondary particles (A) and lithium-based polyanion particles (B) are added, When discharging the positive electrode active material composite for a next battery, excessive contact with the atmosphere can be effectively prevented. As a result, even though it is a wet method, it is possible to effectively prevent water from unexpectedly adsorbing to the lithium composite oxide secondary particles (A) and lithium-based polyanion particles (B) during the process. can.
なお、リチウム二次電池用の正極を作製する際においても、正極活物質と有機溶媒等の分散媒との混合処理を経る、いわゆる湿式法を採用した方法であるが、ここでの湿式法は、本発明の湿式法とは異なる。例えば、正極活物質としてリチウム複合酸化物二次粒子（Ａ）と、粒子（Ａ）よりも脆弱で解砕されやすいリチウム系ポリアニオン粒子（Ｂ）の２種類の粒子を混合して正極を作製する場合、リチウム系ポリアニオン粒子（Ｂ）の解砕によって、粘度が上昇し、得られる電極スラリーが不均一化してしまうことや、集電体に塗工する際のスラリーとしての塗工性が悪化してしまうのを回避するため、リチウム系ポリアニオン粒子（Ｂ）が解砕されないための細部にわたる混合条件の設定や混合装置の選択等が必要となる。
しかしながら、本発明の製造方法であれば、湿式法でありながら、リチウム複合酸化物二次粒子（Ａ）及びリチウム系ポリアニオン粒子（Ｂ）に対して、有機溶媒（Ｄ）を最適な量で用いつつ特定の混合処理を施すことにより、リチウム系ポリアニオン粒子（Ｂ）の造粒物が解砕されるとともに、リチウム系ポリアニオン粒子（Ｂ）がリチウム複合酸化物二次粒子（Ａ）表面に被覆されるため、低い粘度を維持したまま電極スラリーを得ることができる。これによって、集電体への塗工性を有効に高めることも可能となる。
In addition, when producing positive electrodes for lithium secondary batteries, a so-called wet method is used, which involves mixing the positive electrode active material with a dispersion medium such as an organic solvent. , which is different from the wet method of the present invention. For example, a positive electrode is prepared by mixing two types of particles as positive electrode active materials: lithium composite oxide secondary particles (A) and lithium-based polyanion particles (B), which are more fragile than particles (A) and easily crushed. In this case, the viscosity increases due to the crushing of the lithium-based polyanion particles (B), and the resulting electrode slurry becomes non-uniform, and the coating properties of the slurry when applied to the current collector deteriorate. In order to avoid this, it is necessary to set detailed mixing conditions and select a mixing device so that the lithium-based polyanion particles (B) are not crushed.
However, with the production method of the present invention, although it is a wet method, the organic solvent (D) is used in an optimal amount for the lithium composite oxide secondary particles (A) and the lithium-based polyanion particles (B). By carrying out a specific mixing treatment, the granules of the lithium-based polyanion particles (B) are crushed, and the lithium-based polyanion particles (B) are coated on the surface of the lithium composite oxide secondary particles (A). Therefore, electrode slurry can be obtained while maintaining low viscosity. This also makes it possible to effectively improve the coating properties on the current collector.
用い得る有機溶媒（Ｄ）としては、沸点５０℃～１５０℃であり、かつ層状型リチウム複合酸化物二次粒子（Ａ）及びリチウム系ポリアニオン粒子（Ｂ）に対して、不要な化学反応や溶解、物理的吸着を起こさなければ、特に制限されないが、具体的には、メタノール、エタノール、プロパノール、イソブチルアルコール等のアルコール類；アセトン、メチルエチルケトン、ジエチルケトン、メチルプロピルケトン等のケトン類；ヘキサン；ケロシン；Ｎ－メチル－２－ピロリドン；ポリフッ化ビニリデン等から選ばれる１種又は２種以上が挙げられる。なかでも、工程（Ｘ）中における熱によって有機溶媒（Ｄ）が不要に揮発してしまうのを抑制する一方、続く工程（Ｙ）においては有機溶媒（Ｄ）を容易に揮発させる観点から、エタノール、プロパノール、アセトン、ヘキサンから選ばれる１種又は２種以上が好ましく、エタノールがより好ましい。 The organic solvent (D) that can be used has a boiling point of 50°C to 150°C and does not cause unnecessary chemical reactions or dissolution with respect to the layered lithium composite oxide secondary particles (A) and the lithium-based polyanion particles (B). There are no particular restrictions as long as they do not cause physical adsorption, but specifically, alcohols such as methanol, ethanol, propanol, and isobutyl alcohol; ketones such as acetone, methyl ethyl ketone, diethyl ketone, and methyl propyl ketone; hexane; kerosene; ; N-methyl-2-pyrrolidone; polyvinylidene fluoride, and the like. Among them, ethanol is used from the viewpoint of suppressing unnecessary volatilization of the organic solvent (D) due to heat during step (X), while easily volatilizing the organic solvent (D) in the subsequent step (Y). , propanol, acetone, and hexane are preferred, and ethanol is more preferred.
有機溶媒（Ｄ）の配合量は、リチウム系ポリアニオン粒子（Ｂ）１００質量部に対し、３０～３０００質量部であって、好ましくは４０～２５００質量部であり、より好ましくは５０～２４００質量部であり、さらに好ましくは５０～２０００質量部である。
また、有機溶媒（Ｄ）の配合量と、層状型リチウム複合酸化物二次粒子（Ａ）、及び表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）の配合量との質量比（｛（Ａ）+（Ｂ）｝／（Ｄ））は、好ましくは０．２～１０であり、より好ましくは０．２～８であり、さらに好ましくは０．２～６である。
The blending amount of the organic solvent (D) is 30 to 3000 parts by mass, preferably 40 to 2500 parts by mass, and more preferably 50 to 2400 parts by mass, based on 100 parts by mass of the lithium-based polyanion particles (B). and more preferably 50 to 2000 parts by mass.
Also, the mass of the blending amount of the organic solvent (D) and the blending amount of the layered lithium composite oxide secondary particles (A) and the lithium-based polyanion particles (B) having carbon (c) supported on the surface. The ratio ({(A)+(B)}/(D)) is preferably 0.2 to 10, more preferably 0.2 to 8, and even more preferably 0.2 to 6.
リチウム複合酸化物二次粒子（Ａ）の配合量と、表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）の配合量（炭素（ｃ）の担持量を含む）との質量比（（Ａ）：（Ｂ））は、好ましくは９５：５～５０：５０であり、より好ましくは９３：７～５０：５０であり、さらに好ましくは９０：１０～５０：５０である。 Mass of the blending amount of lithium composite oxide secondary particles (A) and the blending amount of lithium-based polyanion particles (B) having carbon (c) supported on the surface (including the supported amount of carbon (c)) The ratio ((A):(B)) is preferably 95:5 to 50:50, more preferably 93:7 to 50:50, even more preferably 90:10 to 50:50.
配合スラリーの温度は、好ましくは１０℃～５０℃であり、より好ましくは１０℃～４５℃である。また、２５℃におけるｐＨは、好ましくは５～１０であり、より好ましくは６～９．５である。 The temperature of the blended slurry is preferably 10°C to 50°C, more preferably 10°C to 45°C. Further, the pH at 25° C. is preferably 5 to 10, more preferably 6 to 9.5.
次いで、工程（Ｘ）では、得られた配合スラリーを圧縮力及びせん断力を付加しながら混合して複合化物スラリーを得る。圧縮力及びせん断力を付加しながらの混合処理としては、具体的には、リチウム系ポリアニオン粒子（Ｂ）の造粒体を解砕しながら、解砕されたリチウム系ポリアニオン粒子（Ｂ）が層状型リチウム複合酸化物二次粒子（Ａ）に被覆するような処理であればよく、かかる処理をインペラ又はロータ工具を備える装置を用いて行うのが好ましい。 Next, in step (X), the obtained blended slurry is mixed while applying compressive force and shear force to obtain a composite slurry. Specifically, the mixing treatment while applying compressive force and shear force includes crushing the granules of the lithium-based polyanion particles (B), and forming the crushed lithium-based polyanion particles (B) into a layered structure. Any treatment may be used as long as it coats the type lithium composite oxide secondary particles (A), and such treatment is preferably carried out using a device equipped with an impeller or rotor tool.
かかるインペラ又はロータ工具を備える装置を用いる場合、インペラ又はロータ工具の周速度は、効果的にリチウム系ポリアニオン粒子（Ｂ）の造粒体を解砕しつつ、層状型リチウム複合酸化物二次粒子（Ａ）に被覆させる観点から、好ましくは１０ｍ／ｓ～４０ｍ／ｓであり、より好ましくは１２ｍ／ｓ～４０ｍ／ｓである。また、混合時間は、好ましくは１分間～９０分間であり、より好ましくは２分間～８０分間である。また混合処理における仕事量は、好ましくは０．５Ｗｈ～７５Ｗｈであり、より好ましくは１Ｗｈ～５０Ｗｈである。
なお、インペラ又はロータ工具の周速度とは、回転式攪拌翼（インペラ）又はロータ工具の最外端部の速度を意味し、下記式（１）により表すことができ、また圧縮力及びせん断力を付加しながら混合する処理を行う時間は、インペラ又はロータ工具の周速度が遅いほど長くなるように、インペラ又はロータ工具の周速度によっても変動し得る。
インペラ又はロータ工具の周速度（ｍ／ｓ）＝
インペラ又はロータ工具の直径（ｍ）×π×回転数（ｒｐｍ）÷６０・・・（１）
仕事量とは、装置の負荷（Ｗ）と処理時間（ｈ）の積で表され、下記式（２）となる。
仕事量（Ｗｈ）＝装置の負荷（Ｗ）×時間（ｈ）・・・（２）
When using a device equipped with such an impeller or rotor tool, the circumferential speed of the impeller or rotor tool is set such that the circumferential speed of the impeller or rotor tool is adjusted to effectively crush the granules of lithium-based polyanion particles (B) while crushing the layered lithium composite oxide secondary particles. From the viewpoint of coating (A), the speed is preferably 10 m/s to 40 m/s, more preferably 12 m/s to 40 m/s. Further, the mixing time is preferably 1 minute to 90 minutes, more preferably 2 minutes to 80 minutes. Further, the amount of work in the mixing process is preferably 0.5Wh to 75Wh, more preferably 1Wh to 50Wh.
Note that the peripheral speed of the impeller or rotor tool means the speed of the outermost end of the rotary stirring blade (impeller) or the rotor tool, and can be expressed by the following formula (1), and the compressive force and shear force The time for performing the mixing process while adding may also vary depending on the circumferential speed of the impeller or rotor tool, such that the slower the circumferential speed of the impeller or rotor tool, the longer it takes.
Circumferential speed of impeller or rotor tool (m/s) =
Impeller or rotor tool diameter (m) x π x rotation speed (rpm) ÷ 60... (1)
The workload is expressed as the product of the device load (W) and the processing time (h), and is expressed by the following formula (2).
Work load (Wh) = Equipment load (W) x time (h)...(2)
かかるインペラ又はロータ工具を備える装置としては、フィルミックス（プライミクス社製）、ヘンシェルミキサ（井元製作所社製）、ハイスピーダー（大平洋機工社製）が挙げられる。例えば、フィルミックス（プライミクス社製）を用いると、容易に高圧縮力とせん断力を付加することが可能であるため、工程（Ｘ）における好ましい装置である。 Examples of devices equipped with such an impeller or rotor tool include Filmix (manufactured by Primix Co., Ltd.), Henschel mixer (manufactured by Imoto Seisakusho Co., Ltd.), and Hi-Speeder (manufactured by Taiheiyo Kiko Co., Ltd.). For example, if Filmix (manufactured by Primix) is used, it is possible to easily apply high compressive force and shearing force, so it is a preferable device in step (X).
本発明のリチウムイオン二次電池用正極活物質複合体の製造方法が備える工程（Ｙ）は、工程（Ｘ）で得られた複合化物スラリーを乾燥する工程である。
具体的には、例えば、真空定温乾燥器（ＶＯＳ－３０１ＳＤ東京理化器械社製）を用い、予め８０℃まで乾燥室内を昇温させた後に、工程（Ｘ）で得られた複合化物スラリーを入れ、真空ポンプを用いて０．９ＭＰａまで減圧し、６時間乾燥を行えばよい。乾燥雰囲気としては真空乾燥が好ましいが、この限りではない。
乾燥温度は、好ましくは５０℃～１５０℃であり、より好ましくは６０℃～１２０℃である。また乾燥時間は、好ましくは３０分～７２００分であり、より好ましくは６０分～１４４０分である。
Step (Y) included in the method for producing a positive electrode active material composite for a lithium ion secondary battery of the present invention is a step of drying the composite slurry obtained in step (X).
Specifically, for example, using a vacuum constant temperature dryer (VOS-301SD manufactured by Tokyo Rikakikai Co., Ltd.), the temperature inside the drying chamber is raised to 80°C in advance, and then the composite compound slurry obtained in step (X) is poured into the drying chamber. , the pressure may be reduced to 0.9 MPa using a vacuum pump, and drying may be performed for 6 hours. Although vacuum drying is preferable as the drying atmosphere, it is not limited to this.
The drying temperature is preferably 50°C to 150°C, more preferably 60°C to 120°C. Further, the drying time is preferably 30 minutes to 7200 minutes, more preferably 60 minutes to 1440 minutes.
本発明の製造方法により得られるリチウムイオン二次電池用正極活物質複合体において、水分含有量は、好ましくは３０００ｐｐｍ以下であり、より好ましくは２０００ｐｐｍ以下であり、さらに好ましくは１０００ｐｐｍ以下である。
なお、本明細書において水分含有量とは、リチウムイオン二次電池用正極活物質複合体を１５０℃まで昇温して２０分間保持した後、さらに温度２５０℃まで昇温して２０分間保持した際に揮発した水分量について、カールフィッシャー水分計（ＭＫＣ－６１０、京都電子工業（株）製）を用いて測定し、リチウムイオン二次電池用正極活物質複合体全量１００質量％中の水分含有量（質量％）に換算した値を意味する。
In the positive electrode active material composite for a lithium ion secondary battery obtained by the production method of the present invention, the water content is preferably 3000 ppm or less, more preferably 2000 ppm or less, and still more preferably 1000 ppm or less.
In this specification, water content refers to the temperature of the positive electrode active material composite for lithium ion secondary batteries heated to 150°C and held for 20 minutes, and then further heated to 250°C and held for 20 minutes. The amount of water vaporized during the process was measured using a Karl Fischer moisture meter (MKC-610, manufactured by Kyoto Electronics Industry Co., Ltd.), and the water content in 100% by mass of the total positive electrode active material composite for lithium ion secondary batteries was measured. It means the value converted to amount (mass%).
本発明の製造方法により得られるリチウムイオン二次電池用正極活物質複合体において、リチウム複合酸化物二次粒子（Ａ）の含有量と、表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）の含有量（炭素（ｃ）の担持量を含む）との質量比（（Ａ）：（Ｂ））は、好ましくは９５：５～５０：５０であり、より好ましくは９３：７～５０：５０であり、さらに好ましくは９０：１０～５０：５０である。 In the positive electrode active material composite for a lithium ion secondary battery obtained by the production method of the present invention, the content of lithium composite oxide secondary particles (A) and the lithium-based polyanion having carbon (c) supported on the surface The mass ratio ((A):(B)) of the content of particles (B) (including the supported amount of carbon (c)) is preferably 95:5 to 50:50, more preferably 93: The ratio is 7 to 50:50, more preferably 90:10 to 50:50.
なお、本発明の製造方法により得られるリチウムイオン二次電池用正極活物質複合体について、層状型リチウム複合酸化物二次粒子（Ａ）の表面において、表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）とリチウム複合酸化物粒子とが複合化してなる程度は、ラマン分光法によって評価することができる。具体的には、ラマン分光法により求められるラマンスペクトルにおいて、リチウム系ポリアニオン粒子（Ｂ）の表面に存在する炭素（ｃ）のピーク強度（Ｇバンド、１６００ｃｍ－１付近、Ｉ（ｃ）とする。）と層状型リチウム複合酸化物二次粒子（Ａ）に含まれる遷移金属と酸素の結合に由来するピーク強度（６００ｃｍ－１付近、Ｉ（Ａ）とする。）との強度比（Ｉ（Ａ）／Ｉ（ｃ））を算出された値により確認することができる。したがって、強度比（Ｉ（Ａ）／Ｉ（ｃ））の値が低いほど、表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）とリチウム複合酸化物粒子とが強固に複合化されてなり、層状型リチウム複合酸化物二次粒子（Ａ）の表面が良好に被覆されていることを示す。
上記強度比（Ｉ（Ａ）／Ｉ（ｃ））の値は、より具体的には、好ましくは０．３以下であり、より好ましくは０．２５であり、さらに好ましくは０．１５以下である。
In addition, regarding the positive electrode active material composite for a lithium ion secondary battery obtained by the production method of the present invention, carbon (c) is supported on the surface of the layered lithium composite oxide secondary particles (A). The degree to which the lithium-based polyanion particles (B) and the lithium composite oxide particles are composited can be evaluated by Raman spectroscopy. Specifically, in the Raman spectrum determined by Raman spectroscopy, the peak intensity of carbon (c) present on the surface of the lithium-based polyanion particles (B) (G band, around 1600 cm-1, I (c)) is defined. ) and the peak intensity (near 600 cm-1, defined as I (A)) derived from the bond between the transition metal and oxygen contained in the layered lithium composite oxide secondary particles (A) (I (A) ) /I (c) ) can be confirmed by the calculated value. Therefore, the lower the value of the strength ratio (I (A) / I (c) ), the more strongly the lithium-based polyanion particles (B) carrying carbon (c) on the surface and the lithium composite oxide particles are combined. It shows that the surface of the layered lithium composite oxide secondary particles (A) is well coated.
More specifically, the value of the intensity ratio (I (A) / I (c) ) is preferably 0.3 or less, more preferably 0.25, and even more preferably 0.15 or less. be.
本発明の二次電池用正極活物質複合体を正極材料として適用し、これを含むリチウムイオン二次電池としては、正極と負極と電解液とセパレータ、若しくは正極と負極と固体電解質を必須構成とするものであれば特に限定されない。 The positive electrode active material composite for secondary batteries of the present invention is applied as a positive electrode material, and a lithium ion secondary battery containing the same includes a positive electrode, a negative electrode, an electrolyte, and a separator, or a positive electrode, a negative electrode, and a solid electrolyte as essential components. There is no particular limitation as long as it is.
ここで、負極については、リチウムイオンを充電時には吸蔵し、かつ放電時には放出することができれば、その材料構成で特に限定されるものではなく、公知の材料構成のものを用いることができる。たとえば、リチウム金属、グラファイト、シリコン系（Ｓｉ、ＳｉＯｘ）、チタン酸リチウム又は非晶質炭素等の炭素材料等を用いることができる。そしてリチウムイオンを電気化学的に吸蔵・放出し得るインターカレート材料で形成された電極、特に炭素材料を用いることが好ましい。さらに、２種以上の上記の負極材料を併用してもよく、たとえばグラファイトとシリコン系の組み合わせを用いることができる。 Here, the material composition of the negative electrode is not particularly limited as long as it can occlude lithium ions during charging and release them during discharging, and any known material composition can be used. For example, lithium metal, graphite, silicon-based (Si, SiO x ), lithium titanate, carbon materials such as amorphous carbon, etc. can be used. It is preferable to use an electrode made of an intercalating material that can electrochemically absorb and release lithium ions, particularly a carbon material. Furthermore, two or more of the above negative electrode materials may be used in combination; for example, a combination of graphite and silicon may be used.
電解液は、有機溶媒に支持塩を溶解させたものである。有機溶媒は、通常リチウムイオン二次電池の電解液の用いられる有機溶媒であれば特に限定されるものではなく、例えば、カーボネート類、ハロゲン化炭化水素、エーテル類、ケトン類、ニトリル類、ラクトン類、オキソラン化合物等を用いることができる。 The electrolytic solution is one in which a supporting salt is dissolved in an organic solvent. The organic solvent is not particularly limited as long as it is an organic solvent that is normally used in electrolytes of lithium ion secondary batteries, and examples include carbonates, halogenated hydrocarbons, ethers, ketones, nitriles, and lactones. , oxolane compounds, etc. can be used.
支持塩は、その種類が特に限定されるものではないが、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣｌＯ４及びＬｉＡｓＦ６から選ばれる無機塩、該無機塩の誘導体、ＬｉＳＯ３ＣＦ３、ＬｉＣ（ＳＯ３ＣＦ３）２及びＬｉＮ（ＳＯ３ＣＦ３）２、ＬｉＮ（ＳＯ２Ｃ２Ｆ５）２及びＬｉＮ（ＳＯ２ＣＦ３）（ＳＯ２Ｃ４Ｆ９）から選ばれる有機塩、並びに該有機塩の誘導体の少なくとも１種であることが好ましい。 The supporting salt is not particularly limited in type, but includes inorganic salts selected from LiPF 6 , LiBF 4 , LiClO 4 and LiAsF 6 , derivatives of the inorganic salts, LiSO 3 CF 3 , LiC(SO 3 CF 3 ) 2 and an organic salt selected from LiN(SO 3 CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 and LiN(SO 2 CF 3 ) (SO 2 C 4 F 9 ), and a derivative of the organic salt It is preferable that it is at least one kind of.
セパレータは、正極及び負極を電気的に絶縁し、電解液を保持する役割を果たすものである。たとえば、多孔性合成樹脂膜、特にポリオレフィン系高分子（ポリエチレン、ポリプロピレン）の多孔膜を用いればよい。 The separator serves to electrically insulate the positive electrode and the negative electrode and to retain the electrolyte. For example, a porous synthetic resin membrane, particularly a porous membrane of polyolefin polymer (polyethylene, polypropylene) may be used.
固体電解質は、正極及び負極を電気的に絶縁し、高いリチウムイオン電導性を示すものである。たとえば、Ｌａ０．５１Ｌｉ０．３４ＴｉＯ２．９４、Ｌｉ１．３Ａｌ０．３Ｔｉ１．７（ＰＯ４）３、Ｌｉ７Ｌａ３Ｚｒ２Ｏ１２、５０Ｌｉ４ＳｉＯ４・５０Ｌｉ３ＢＯ３、Ｌｉ２．９ＰＯ３．３Ｎ０．４６、Ｌｉ３．６Ｓｉ０．６Ｐ０．４Ｏ４、Ｌｉ１．０７Ａｌ０．６９Ｔｉ１．４６（ＰＯ４）３、Ｌｉ１．５Ａｌ０．５Ｇｅ１．５（ＰＯ４）３、Ｌｉ１０ＧｅＰ２Ｓ１２、Ｌｉ３．２５Ｇｅ０．２５Ｐ０．７５Ｓ４、３０Ｌｉ２Ｓ・２６Ｂ２Ｓ３・４４ＬｉＩ、６３Ｌｉ２Ｓ・３６ＳｉＳ２・１Ｌｉ３ＰＯ４、５７Ｌｉ２Ｓ・３８ＳｉＳ２・５Ｌｉ４ＳｉＯ４、７０Ｌｉ２Ｓ・３０Ｐ２Ｓ５、５０Ｌｉ２Ｓ・５０ＧｅＳ２、Ｌｉ７Ｐ３Ｓ１１、Ｌｉ３．２５Ｐ０．９５Ｓ４を用いればよい。 A solid electrolyte electrically insulates a positive electrode and a negative electrode and exhibits high lithium ion conductivity. For example, La 0.51 Li 0.34 TiO 2.94 , Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 , Li 7 La 3 Zr 2 O 12 , 50Li 4 SiO 4.50Li 3 BO 3 , Li 2.9 PO 3.3 N 0.46 , Li 3.6 Si 0.6 P 0.4 O 4 , Li 1.07 Al 0.69 Ti 1.46 (PO 4 ) 3 , Li 1 .5 Al 0.5 Ge 1.5 (PO 4 ) 3 , Li 10 GeP 2 S 12 , Li 3.25 Ge 0.25 P 0.75 S 4 , 30Li 2 S・26B 2 S 3・44LiI, 63Li 2S・36SiS 2・1Li 3 PO 4 , 57Li 2 S・38SiS 2・5Li 4 SiO 4 , 70Li 2 S・30P 2 S 5 , 50Li 2 S・50GeS 2 , Li 7 P 3 S 11 , Li 3.25 P 0.95 S 4 may be used.
上記の構成を有するリチウムイオン二次電池の形状としては、特に制限を受けるものではなく、コイン型、円筒型、角型等種々の形状や、ラミネート外装体に封入した不定形状であってもよい。 The shape of the lithium ion secondary battery having the above configuration is not particularly limited, and may be various shapes such as a coin shape, a cylindrical shape, a square shape, or an irregular shape enclosed in a laminate exterior body. .
以下、本発明について、実施例に基づき具体的に説明するが、本発明はこれら実施例に限定されるものではない。 Hereinafter, the present invention will be specifically explained based on Examples, but the present invention is not limited to these Examples.
［製造例１：層状型リチウム複合酸化物二次粒子（Ａ）の製造］
Ｎｉ：Ｃｏ：Ｍｎのモル比が１：１：１となるように、硫酸ニッケル六水和物 ２６３ｇ、硫酸コバルト七水和物 ２８１ｇ、硫酸マンガン五水和物 ２４１ｇ、及び水 ３Ｌを混合した。次いで、かかる混合液に滴下速度３００ｍｌ／分で２５％アンモニア水を滴下し、２５℃におけるｐＨが１１の金属複合水酸化物を含むスラリーａ１を得た。
次いで、スラリーａ１をろ過、乾燥して、金属複合水酸化物の混合物ａ２を得た後、かかる混合物ａ２に炭酸リチウム３７gをボールミルで混合して粉末混合物ａ３を得た。
得られた粉末混合物ａ３を、空気雰囲気下で８００℃×５時間仮焼成して解砕した後、空気雰囲気下で８００℃×１０時間本焼成し、層状型リチウム複合酸化物二次粒子（ＬｉＮｉ0.33Ｃｏ0.33Ｍｎ0.34Ｏ2、平均粒径：１０μｍ、ＢＥＴ比表面積：０．３ｍ２／ｇ）を得た。
[Production Example 1: Production of layered lithium composite oxide secondary particles (A)]
263 g of nickel sulfate hexahydrate, 281 g of cobalt sulfate heptahydrate, 241 g of manganese sulfate pentahydrate, and 3 L of water were mixed so that the molar ratio of Ni:Co:Mn was 1:1:1. Next, 25% ammonia water was added dropwise to the mixed solution at a dropping rate of 300 ml/min to obtain a slurry a1 containing metal composite hydroxide having a pH of 11 at 25°C.
Next, the slurry a1 was filtered and dried to obtain a metal composite hydroxide mixture a2, and then 37 g of lithium carbonate was mixed with the mixture a2 using a ball mill to obtain a powder mixture a3.
The obtained powder mixture a3 was pre-calcined in an air atmosphere at 800°C for 5 hours and crushed, and then main-calcined in an air atmosphere at 800°C for 10 hours to form layered lithium composite oxide secondary particles (LiNi 0.33 Co 0.33 Mn 0.34 O 2 , average particle size: 10 μm, BET specific surface area: 0.3 m 2 /g).
［製造例２：表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）の製造］
ＬｉＯＨ・Ｈ２Ｏ ４０７１ｇ、及び水９．６５７Ｌを混合してスラリーｂ１を得た。 次いで、得られたスラリーｂ１を、２５℃の温度に保持しながら３分間撹拌しつつ７５％のリン酸水溶液４２０４ｇを４０ｍＬ／分で滴下して、Ｌｉ３ＰＯ４を含むスラリーｂ２を得た。
得られたスラリーｂ２に窒素パージして、スラリーｂ２の溶存酸素濃度を０．１ｍｇ／Ｌとした後、スラリーｂ２全量に対し、ＭｎＳＯ４・５Ｈ２Ｏ ３８０７ｇ、ＦｅＳＯ４・７Ｈ２Ｏ ２６８４ｇを添加してスラリーｂ３を得た。添加したＭｎＳＯ４とＦｅＳＯ４のモル比（マンガン化合物：鉄化合物）は、７０：３０であった。
次いで、得られたスラリーｂ３をオートクレーブに投入し、１６０℃で１時間水熱反応を行った。オートクレーブ内の圧力は０．８ＭＰａであった。水熱反応後、生成した結晶をろ過し、次いで結晶１質量部に対し１２質量部の水により洗浄した。その後フィルタープレス装置で脱水し、脱水ケーキｂ４を得た。
脱水ケーキｂ４中のリチウム系ポリアニオン粒子の平均粒径は、ＳＥＭ観察を行った結果、１００ｎｍであった。
得られた脱水ケーキｂ４を８０００ｇ分取し、セルロースナノファイバー（ＦＤ１００Ｆ、ダイセルファインケム社製）１２００ｇ、水８．５Ｌを添加して、固形分濃度３０％のスラリーｂ５を得た。得られたスラリーｂ５を超音波攪拌機（Ｔ２５、ＩＫＡ社製）で１０分間分散処理して全体を均一に混合させた後、スプレードライ装置（ＭＤＬ－０５０Ｍ、藤崎電機株式会社製）を用いて乾燥温度１３０℃で噴霧乾燥し、造粒体ｂ６を得た。
得られた造粒体ｂ６を、アルゴン水素雰囲気下（水素濃度３％）、７００℃で１時間焼成して、２．４質量％のセルロースナノファイバー由来の炭素が担持されたリン酸マンガン鉄リチウム二次粒子（ＬｉＦｅ0.3Ｍｎ0.7ＰＯ4、炭素の担持量＝２．０質量％、平均粒径：１２μｍ、ＢＥＴ比表面積：２０．２ｍ２／ｇ）を得た。
[Production Example 2: Production of lithium-based polyanion particles (B) with carbon (c) supported on the surface]
Slurry b1 was obtained by mixing 4071 g of LiOH·H 2 O and 9.657 L of water. Next, 4204 g of a 75% phosphoric acid aqueous solution was added dropwise to the obtained slurry b1 at a rate of 40 mL/min while stirring for 3 minutes while maintaining the temperature at 25° C. to obtain a slurry b2 containing Li 3 PO 4 .
After purging the obtained slurry b2 with nitrogen to make the dissolved oxygen concentration of slurry b2 0.1 mg/L, 3807 g of MnSO 4 .5H 2 O and 2684 g of FeSO 4 .7H 2 O were added to the total amount of slurry b2. Slurry b3 was obtained. The molar ratio of added MnSO 4 and FeSO 4 (manganese compound: iron compound) was 70:30.
Next, the obtained slurry b3 was put into an autoclave, and a hydrothermal reaction was performed at 160° C. for 1 hour. The pressure inside the autoclave was 0.8 MPa. After the hydrothermal reaction, the produced crystals were filtered and then washed with 12 parts by weight of water per 1 part by weight of the crystals. Thereafter, it was dehydrated using a filter press to obtain a dehydrated cake b4.
As a result of SEM observation, the average particle size of the lithium-based polyanion particles in the dehydrated cake b4 was 100 nm.
8,000 g of the obtained dehydrated cake b4 was collected, and 1,200 g of cellulose nanofibers (FD100F, manufactured by Daicel FineChem) and 8.5 L of water were added to obtain slurry b5 with a solid content concentration of 30%. The obtained slurry b5 was dispersed for 10 minutes using an ultrasonic stirrer (T25, manufactured by IKA) to mix the whole uniformly, and then dried using a spray dryer (MDL-050M, manufactured by Fujisaki Electric Co., Ltd.). Spray drying was performed at a temperature of 130°C to obtain granules b6.
The obtained granules b6 were fired at 700°C for 1 hour in an argon-hydrogen atmosphere (hydrogen concentration 3%) to produce lithium manganese iron phosphate on which 2.4% by mass of carbon derived from cellulose nanofibers was supported. Secondary particles (LiFe 0.3 Mn 0.7 PO 4 , supported amount of carbon = 2.0% by mass, average particle size: 12 μm, BET specific surface area: 20.2 m 2 /g) were obtained.
［実施例１］
製造例１で得られた層状型リチウム複合酸化物二次粒子（Ａ） ８．１ｇ、製造例２で得られたリチウム系ポリアニオン粒子（Ｂ） ０．９ｇ、無水エタノール（富士フィルム和光純薬社製、一級） ６ｇを採取し、プライミックス社製フィルミックス３０－Ｌ型（インペラの直径：２３ｍｍ）を用いて１２０００ｒｐｍ（インペラの周速：２８．９ｍ／ｓ）にて１０分間混錬を行い、複合化物スラリーｘを得た。このとき、複合化装置の運転中の電力は３３Ｗであり、仕事量は５．５Ｗｈであった。次いで、得られた複合化物スラリーｘを８０℃の真空乾燥機内で６時間乾燥させて、リチウムイオン二次電池用正極活物質複合体を得た。このとき、インペラの周速（ｍ／ｓ）は、周速（ｍ／ｓ）＝インペラの直径（ｍ）×π×回転数／６０から算出した値とした。また、仕事量は、仕事量（Ｗｈ）＝複合化装置の運転中の電力（Ｗ）×装置運転時間（ｈ）の積から算出した値とした。
[Example 1]
8.1 g of layered lithium composite oxide secondary particles (A) obtained in Production Example 1, 0.9 g of lithium-based polyanion particles (B) obtained in Production Example 2, anhydrous ethanol (Fuji Film Wako Pure Chemical Industries, Ltd.) 6 g was collected and kneaded for 10 minutes at 12,000 rpm (impeller circumferential speed: 28.9 m/s) using Primex's Filmix 30-L type (impeller diameter: 23 mm). , a composite slurry x was obtained. At this time, the power during operation of the compounding device was 33 W, and the amount of work was 5.5 Wh. Next, the obtained composite slurry x was dried in a vacuum dryer at 80° C. for 6 hours to obtain a positive electrode active material composite for a lithium ion secondary battery. At this time, the circumferential speed (m/s) of the impeller was a value calculated from circumferential speed (m/s)=impeller diameter (m)×π×rotation speed/60. Further, the amount of work was a value calculated from the product of amount of work (Wh) = electric power (W) during operation of the compounding device x device operating time (h).
［実施例２］
層状型リチウム複合酸化物二次粒子（Ａ）を６．３ｇ、リチウム系ポリアニオン粒子（Ｂ）を２．７ｇ採取し、複合化装置における諸条件を表１に示す値とした以外、実施例１と同様にしてリチウムイオン二次電池用正極活物質複合体を得た。
[Example 2]
Example 1 except that 6.3 g of layered lithium composite oxide secondary particles (A) and 2.7 g of lithium-based polyanion particles (B) were collected, and the various conditions in the composite device were set to the values shown in Table 1. A positive electrode active material composite for a lithium ion secondary battery was obtained in the same manner as above.
［実施例３］
層状型リチウム複合酸化物二次粒子（Ａ）を４．５ｇ、リチウム系ポリアニオン粒子（Ｂ）を４．５ｇ採取し、複合化装置における諸条件を表１に示す値とした以外、実施例１と同様にしてリチウムイオン二次電池用正極活物質複合体を得た。
[Example 3]
Example 1 except that 4.5 g of layered lithium composite oxide secondary particles (A) and 4.5 g of lithium-based polyanion particles (B) were collected, and the various conditions in the composite device were set to the values shown in Table 1. A positive electrode active material composite for a lithium ion secondary battery was obtained in the same manner as above.
［実施例４］
層状型リチウム複合酸化物二次粒子（Ａ）を６．３ｇ、リチウム系ポリアニオン粒子（Ｂ）を２．７ｇ、無水エタノールを９ｇ採取し、複合化装置における諸条件を表１に示す値とした以外、実施例１と同様にしてリチウムイオン二次電池用正極活物質複合体を得た。
[Example 4]
6.3 g of layered lithium composite oxide secondary particles (A), 2.7 g of lithium-based polyanion particles (B), and 9 g of absolute ethanol were collected, and the various conditions in the composite device were set to the values shown in Table 1. Except for this, a positive electrode active material composite for a lithium ion secondary battery was obtained in the same manner as in Example 1.
［実施例５］
層状型リチウム複合酸化物二次粒子（Ａ）を６．３ｇ、リチウム系ポリアニオン粒子（Ｂ）を２．７ｇ、無水エタノールを２ｇ採取し、複合化装置における諸条件を表１に示す値とした以外、実施例１と同様にしてリチウムイオン二次電池用正極活物質複合体を得た。
[Example 5]
6.3 g of layered lithium composite oxide secondary particles (A), 2.7 g of lithium-based polyanion particles (B), and 2 g of absolute ethanol were collected, and the various conditions in the composite device were set to the values shown in Table 1. Except for this, a positive electrode active material composite for a lithium ion secondary battery was obtained in the same manner as in Example 1.
［実施例６］
層状型リチウム複合酸化物二次粒子（Ａ）を２．１ｇ、リチウム系ポリアニオン粒子（Ｂ）を０．９ｇ、無水エタノールを１５ｇ採取し、複合化装置における諸条件を表１に示す値とした以外、実施例１と同様にしてリチウムイオン二次電池用正極活物質複合体を得た。
[Example 6]
2.1 g of layered lithium composite oxide secondary particles (A), 0.9 g of lithium-based polyanion particles (B), and 15 g of absolute ethanol were collected, and the various conditions in the composite device were set to the values shown in Table 1. Except for this, a positive electrode active material composite for a lithium ion secondary battery was obtained in the same manner as in Example 1.
［実施例７］
有機溶媒（Ｄ）をメタノールとし、複合化装置における諸条件を表１に示す値とした以外、実施例２と同様にしてリチウムイオン二次電池用正極活物質複合体を得た。
[Example 7]
A positive electrode active material composite for a lithium ion secondary battery was obtained in the same manner as in Example 2, except that methanol was used as the organic solvent (D) and the various conditions in the composite device were set to the values shown in Table 1.
［実施例８］
有機溶媒（Ｄ）を２－プロパノールとし、複合化装置における諸条件を表１に示す値とした以外、実施例２と同様にしてリチウムイオン二次電池用正極活物質複合体を得た。
[Example 8]
A positive electrode active material composite for a lithium ion secondary battery was obtained in the same manner as in Example 2, except that the organic solvent (D) was 2-propanol and the various conditions in the composite device were set to the values shown in Table 1.
［実施例９］
有機溶媒（Ｄ）をアセトンとし、複合化装置における諸条件を表１に示す値とした以外、実施例２と同様にしてリチウムイオン二次電池用正極活物質複合体を得た。
[Example 9]
A positive electrode active material composite for a lithium ion secondary battery was obtained in the same manner as in Example 2, except that acetone was used as the organic solvent (D) and the various conditions in the composite apparatus were set to the values shown in Table 1.
［実施例１０～１３］
有機溶媒（Ｄ）をｎ－ヘキサンとし、複合化装置における諸条件を表１に示す値とした以外、実施例２と同様にしてリチウムイオン二次電池用正極活物質複合体を得た。
[Examples 10 to 13]
A positive electrode active material composite for a lithium ion secondary battery was obtained in the same manner as in Example 2, except that the organic solvent (D) was n-hexane and the various conditions in the composite device were set to the values shown in Table 1.
［実施例１４～１５］
複合化装置における諸条件を表１に示す値とした以外、実施例２と同様にして、リチウムイオン二次電池用正極活物質複合体を得た。
[Examples 14-15]
A positive electrode active material composite for a lithium ion secondary battery was obtained in the same manner as in Example 2, except that the various conditions in the composite device were set to the values shown in Table 1.
［比較例１］
有機溶媒（Ｄ）の代わりに水を用い、複合化装置における諸条件を表１に示す値とした以外、実施例２と同様にしてリチウムイオン二次電池用正極活物質複合体を得た。
[Comparative example 1]
A positive electrode active material composite for a lithium ion secondary battery was obtained in the same manner as in Example 2, except that water was used instead of the organic solvent (D) and the various conditions in the composite device were set to the values shown in Table 1.
［比較例２］
層状型リチウム複合酸化物二次粒子（Ａ） ４５０ｇ、リチウム系ポリアニオン粒子（Ｂ） ５０ｇを採取し、ノビルタ(ホソカワミクロン社製、ＮＯＢ－１３０)を用いて２０００ｒｐｍで５分間の複合化処理、いわゆる乾式混合を行って、リチウムイオン二次電池用正極活物質複合体を得た。
[Comparative example 2]
450 g of layered lithium composite oxide secondary particles (A) and 50 g of lithium-based polyanion particles (B) were collected and subjected to a composite treatment using Nobilta (manufactured by Hosokawa Micron, NOB-130) at 2000 rpm for 5 minutes, a so-called dry process. The mixture was mixed to obtain a positive electrode active material composite for a lithium ion secondary battery.
［比較例３］
層状型リチウム複合酸化物二次粒子（Ａ） ３５０ｇ、リチウム系ポリアニオン粒子（Ｂ） １５０ｇを採取した以外、比較例４と同様にしてリチウムイオン二次電池用正極活物質複合体を得た。
[Comparative example 3]
A positive electrode active material composite for a lithium ion secondary battery was obtained in the same manner as in Comparative Example 4, except that 350 g of layered lithium composite oxide secondary particles (A) and 150 g of lithium-based polyanion particles (B) were collected.
［比較例４］
層状型リチウム複合酸化物二次粒子（Ａ） ２５０ｇ、リチウム系ポリアニオン粒子（Ｂ） ２５０ｇを採取し、かつ複合化処理を１５分間とした以外、比較例４と同様にしてリチウムイオン二次電池用正極活物質複合体を得た。
[Comparative example 4]
A process for a lithium ion secondary battery was carried out in the same manner as in Comparative Example 4, except that 250 g of layered lithium composite oxide secondary particles (A) and 250 g of lithium-based polyanion particles (B) were collected, and the composite treatment was performed for 15 minutes. A positive electrode active material composite was obtained.
《リチウムイオン二次電池における放電容量の評価》
得られたリチウムイオン二次電池用正極活物質複合体 ２．７ｇを正極活物質として用い、これにポリフッ化ビニリデン（ＰＶＤＦ） ０．１５０ｇ、Ｎ－メチル－２－ピロリドン（ＮＭＰ） ４．２ｍＬ及びアセチレンブラック ０．１５００ｇを添加し、自転・公転ミキサー（あわとり練太郎（登録商標）ＡＲＥ－３１０、ＴＨＩＮＫＹ社製）を用いて５０００ｒｐｍにて５分間混錬を行ってペーストを得た。次いで、得られたペーストをアルミニウム箔の集電体に塗工し、８０℃の真空乾燥機中で６時間乾燥を行った後にプレスを行って、リチウムイオン二次電池用の正極を得た。次いで、得られた正極を用い、コイン電池を作製した。
得られたコイン電池を用い、放電容量測定装置（ＨＪ－１００１ＳＤ８、北斗電工社製）にて、気温３０℃環境での０．１Ｃ（１７ｍＡｈ／ｇ）、３Ｃ（５１０ｍＡｈ／ｇ）各々の放電容量を測定した。
《Evaluation of discharge capacity in lithium ion secondary batteries》
2.7 g of the obtained positive electrode active material composite for lithium ion secondary batteries was used as a positive electrode active material, and to this was added 0.150 g of polyvinylidene fluoride (PVDF), 4.2 mL of N-methyl-2-pyrrolidone (NMP), and 0.1500 g of acetylene black was added and kneaded for 5 minutes at 5000 rpm using a rotation/revolution mixer (Awatori Rentaro (registered trademark) ARE-310, manufactured by THINKY) to obtain a paste. Next, the obtained paste was applied to an aluminum foil current collector, dried in a vacuum dryer at 80° C. for 6 hours, and then pressed to obtain a positive electrode for a lithium ion secondary battery. Next, a coin battery was produced using the obtained positive electrode.
Using the obtained coin battery, the discharge capacity was measured at 0.1C (17mAh/g) and 3C (510mAh/g) at a temperature of 30°C using a discharge capacity measuring device (HJ-1001SD8, manufactured by Hokuto Denko Co., Ltd.). was measured.
《層状型リチウム複合酸化物二次粒子（Ａ）表面におけるリチウム系ポリアニオン粒子（Ｂ）の被覆の程度の評価》
ラマン分光光度計（ＮＲＳ－１０００、日本分光社製）を用いてラマン分光スペクトルを測定し、１６００ｃｍ－１付近（Ｇバンド）のピーク強度（Ｉ（Ａ））と６００ｃｍ－１付近のピーク強度（Ｉ（C））を求め、強度比（Ｉ（Ａ）／Ｉ（C））を算出して、被覆の程度を評価した。
かかる強度比の値が小さいほど、層状型リチウム複合酸化物二次粒子（Ａ）表面において強固にリチウム系ポリアニオン粒子（Ｂ）が被覆されていることを示す。
<<Evaluation of the degree of coverage of the lithium-based polyanion particles (B) on the surface of the layered lithium composite oxide secondary particles (A)>>
Raman spectra were measured using a Raman spectrophotometer (NRS-1000, manufactured by JASCO Corporation), and the peak intensity (I (A) ) around 1600 cm -1 (G band) and the peak intensity around 600 cm -1 ( I (C) ) was determined, and the intensity ratio (I (A) /I (C) ) was calculated to evaluate the degree of coverage.
The smaller the value of the intensity ratio, the more firmly the surface of the layered lithium composite oxide secondary particles (A) is coated with the lithium-based polyanion particles (B).
《リチウムイオン二次電池用正極活物質複合体の水分含有量の測定》
得られたリチウムイオン二次電池用正極活物質複合体を１５０℃まで昇温して２０分間保持した後、さらに温度２５０℃まで昇温して２０分間保持した際に揮発した水分量について、カールフィッシャー水分計（ＭＫＣ－６１０、京都電子工業（株）製）を用いて測定し、水分含有量（質量％）に換算した値を算出した。
《Measurement of water content of positive electrode active material composite for lithium ion secondary batteries》
The resulting positive electrode active material composite for lithium ion secondary batteries was heated to 150°C and held for 20 minutes, and then further heated to 250°C and held for 20 minutes. It was measured using a Fisher moisture meter (MKC-610, manufactured by Kyoto Electronics Industry Co., Ltd.), and the value converted to water content (mass %) was calculated.
表１～２の結果によれば、実施例の製造方法により得られたリチウムイオン二次電池用正極活物質複合体は、比較例の製造方法により得られたリチウムイオン二次電池用正極活物質複合体に比して、電池特性は同等ではあるものの、水分含有量が有効に低減されていることがわかる。 According to the results in Tables 1 and 2, the positive electrode active material composite for lithium ion secondary batteries obtained by the manufacturing method of the example is different from the positive electrode active material composite for lithium ion secondary batteries obtained by the manufacturing method of the comparative example. It can be seen that although the battery characteristics are the same as those of the composite, the water content is effectively reduced.
Claims (6)
ＬｉＮｉａＣｏｂＭｎｃＭ１ ｘＯ２・・・（Ｉ）
（式（Ｉ）中、Ｍ１はＭｇ、Ｔｉ、Ｎｂ、Ｆｅ、Ｃｒ、Ｓｉ、Ａｌ、Ｇａ、Ｖ、Ｚｎ、Ｃｕ、Ｓｒ、Ｍｏ、Ｚｒ、Ｓｎ、Ｔａ、Ｗ、Ｌａ、Ｃｅ、Ｐｂ、Ｂｉ及びＧｅから選ばれる１種又は２種以上の元素を示す。ａ、ｂ、ｃ、ｘは、０．３≦ａ＜１、０＜ｂ≦０．７、０＜ｃ≦０．７、０≦ｘ≦０．３、かつ３ａ＋３ｂ＋３ｃ＋（Ｍ１の価数）×ｘ＝３を満たす数を示す。）
ＬｉＮｉｄＣｏｅＡｌｆＭ２ ｙＯ２・・・（II）
（式（II）中、Ｍ２はＭｇ、Ｔｉ、Ｎｂ、Ｆｅ、Ｃｒ、Ｓｉ、Ｇａ、Ｖ、Ｚｎ、Ｃｕ、Ｓｒ、Ｍｏ、Ｚｒ、Ｓｎ、Ｔａ、Ｗ、Ｌａ、Ｃｅ、Ｐｂ、Ｂｉ及びＧｅから選ばれる１種又は２種以上の元素を示す。ｄ、ｅ、ｆ、ｙは、０．４≦ｄ＜１、０＜ｅ≦０．６、０＜ｆ≦０．３、０≦ｙ≦０．３、かつ３ｄ＋３ｅ＋３ｆ＋（Ｍ２の価数）×ｙ＝３を満たす数を示す。）
で表されるリチウム複合酸化物粒子からなる層状型リチウム複合酸化物二次粒子（Ａ）の表面において、下記式（III）又は式（IV）:
ＬｉＣｏｐＭ３ ｚＰＯ４・・・（III）
（式（III）中、Ｍ３はＦｅ、Ｍｎ、Ｍｇ、Ｃａ、Ｓｒ、Ｙ、Ｚｒ、Ｍｏ、Ｂａ、Ｐｂ、Ｂｉ、Ｌａ、Ｃｅ、Ｎｄ又はＧｄを示す。ｐ及びｚは、０．３＜ｐ≦１、０≦ｚ≦０．３、及び２ｐ＋（Ｍ３の価数）×ｚ＝２を満たす数を示す。）
ＬｉＦｅｑＭｎｒＭ４ ｖＰＯ４・・・（IV）
（式（IV）中、Ｍ４はＣｏ、Ｍｇ、Ｃａ、Ｓｒ、Ｙ、Ｚｒ、Ｍｏ、Ｂａ、Ｐｂ、Ｂｉ、Ｌａ、Ｃｅ、Ｎｄ又はＧｄを示す。ｑ、ｒ、及びｖは、０≦ｑ≦１、０≦ｒ≦１、０≦ｖ≦０．３、及びｑ＋ｒ≠０を満たし、かつ２ｑ＋２ｒ＋（Ｍ４の価数）×ｖ＝２を満たす数を示す。）
で表され、表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）と、リチウム複合酸化物粒子とが複合化してなるリチウムイオン二次電池用正極活物質複合体の製造方法であって、次の工程（Ｘ）～（Ｙ）：
（Ｘ）層状型リチウム複合酸化物二次粒子（Ａ）、及び表面に炭素（ｃ）が担持してなるリチウム系ポリアニオン粒子（Ｂ）と、リチウム系ポリアニオン粒子（Ｂ）１００質量部に対して３０質量部～３０００質量部である沸点５０℃～１５０℃の有機溶媒（Ｄ）とを配合し、得られた配合スラリーを圧縮力及びせん断力を付加しながら混合して複合化物スラリーを得る工程
（Ｙ）得られた複合化物スラリーを乾燥する工程
を備えるリチウムイオン二次電池用正極活物質複合体の製造方法。 The following formula (I) or formula (II):
LiNi a Co b Mn c M 1 x O 2 ...(I)
(In formula (I), M1 is Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Represents one or more elements selected from Bi and Ge. a, b, c, x are 0.3≦a<1, 0<b≦0.7, 0<c≦0.7, Indicates a number that satisfies 0≦x≦0.3 and 3a+3b+3c+(M valence of 1 )×x=3.)
LiNi d Co e Al f M 2 y O 2 ...(II)
(In formula (II), M2 is Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi and Represents one or more elements selected from Ge. d, e, f, y are 0.4≦d<1, 0<e≦0.6, 0<f≦0.3, 0≦ Indicates a number that satisfies y≦0.3 and 3d+3e+3f+(valence of M2 )×y=3.)
On the surface of layered lithium composite oxide secondary particles (A) consisting of lithium composite oxide particles represented by the following formula (III) or formula (IV):
LiCo p M 3 z PO 4 ...(III)
(In formula (III), M3 represents Fe, Mn, Mg, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. p and z are 0.3 <Indicates a number that satisfies p≦1, 0≦z≦0.3, and 2p+(valence of M3 )×z=2.)
LiFe q Mn r M 4 v PO 4 ...(IV)
(In formula (IV), M 4 represents Co, Mg, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. q, r, and v are 0≦ Indicates a number that satisfies q≦1, 0≦r≦1, 0≦v≦0.3, and q+r≠0, and 2q+2r+(valence of M4 )×v=2.)
A method for producing a positive electrode active material composite for a lithium ion secondary battery, which is a composite of lithium-based polyanion particles (B), which are represented by the following and carbon (c) is supported on the surface, and lithium composite oxide particles. Then, the next steps (X) to (Y):
(X) Layered lithium composite oxide secondary particles (A), lithium-based polyanion particles (B) with carbon (c) supported on the surface, and 100 parts by mass of the lithium-based polyanion particles (B) A step of blending 30 parts by mass to 3000 parts by mass of an organic solvent (D) with a boiling point of 50°C to 150°C and mixing the resulting blended slurry while applying compressive force and shearing force to obtain a composite slurry. (Y) A method for producing a positive electrode active material composite for a lithium ion secondary battery, comprising the step of drying the obtained composite slurry.
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