JP2016119288A - Mixed active material for lithium secondary battery, positive electrode for lithium secondary battery, and lithium secondary battery - Google Patents

Mixed active material for lithium secondary battery, positive electrode for lithium secondary battery, and lithium secondary battery Download PDF

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JP2016119288A
JP2016119288A JP2015178055A JP2015178055A JP2016119288A JP 2016119288 A JP2016119288 A JP 2016119288A JP 2015178055 A JP2015178055 A JP 2015178055A JP 2015178055 A JP2015178055 A JP 2015178055A JP 2016119288 A JP2016119288 A JP 2016119288A
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遠藤　大輔
Daisuke Endo
大輔 遠藤
井上　直樹
Naoki Inoue
直樹 井上
広樹 北村
Hiroki Kitamura
広樹 北村
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GS Yuasa Corp
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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
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Abstract

PROBLEM TO BE SOLVED: To provide a mixed active material capable of simultaneously achieving single electrode electrochemical characteristics and filling property (low porosity) at the positive electrode of a lithium secondary battery by mixing a "lithium excessive type" active material with a "LiMeOtype" active material, a positive electrode using the mixed active material, and a lithium secondary battery including the positive electrode.SOLUTION: The mixed active material for the lithium secondary battery, prepared by mixing a lithium excessive type lithium transition metal composite oxide (1<Li/Me 1<1.5, Mn/Me 1>0.5) and LiMe2O(0<Mn/Me 2≤0.5) including Co, Ni, and Mn as transition metals Me 1 and Me 2, is characterized in that 50 to 85 mass% of the lithium excessive type lithium transition metal composite oxide is contained in the mixed active material, the average particle size of the lithium excessive type lithium transition metal composite oxide is smaller than that of LiMe2O, and a peak differential pore volume is equal to or more than 0.85 mm/(g nm).SELECTED DRAWING: None

Description

本発明は、新規なリチウム遷移金属複合酸化物を含むリチウム二次電池用混合活物質、その混合活物質を含有するリチウム二次電池用正極、及び、その正極を備えたリチウム二次電池に関する。   The present invention relates to a mixed active material for a lithium secondary battery including a novel lithium transition metal composite oxide, a positive electrode for a lithium secondary battery containing the mixed active material, and a lithium secondary battery including the positive electrode.

従来、リチウム二次電池用正極活物質として、α−ＮａＦｅＯ２型結晶構造を有する「ＬｉＭｅＯ２型」活物質（Ｍｅは遷移金属）が検討され、ＬｉＣｏＯ２を用いたリチウム二次電池が広く実用化されていた。しかし、ＬｉＣｏＯ２の放電容量は１２０〜１３０ｍＡｈ／ｇ程度であった。前記Ｍｅとして、地球資源として豊富なＭｎを用いることが望まれてきた。しかし、ＭｅとしてＭｎを含有させた「ＬｉＭｅＯ２型」活物質は、Ｍｅに対するＭｎのモル比Ｍｎ／Ｍｅが０．５を超える場合には、充電をするとスピネル型へと構造変化が起こり、結晶構造が維持できないため、充放電サイクル性能が著しく劣るという問題があった。 Conventionally, as a positive electrode active material for a lithium secondary battery, a “LiMeO 2 type” active material (Me is a transition metal) having an α-NaFeO 2 type crystal structure has been studied, and lithium secondary batteries using LiCoO 2 have been widely put into practical use. It was converted. However, the discharge capacity of LiCoO 2 was about 120 to 130 mAh / g. As Me, it has been desired to use abundant Mn as a global resource. However, the “LiMeO 2 type” active material containing Mn as Me, when the molar ratio of Mn to Me, Mn / Me exceeds 0.5, the structure changes to spinel type when charged, Since the structure could not be maintained, there was a problem that the charge / discharge cycle performance was extremely inferior.

そこで、Ｍｅに対するＭｎのモル比Ｍｎ／Ｍｅが０．５以下であり、充放電サイクル性能の点でも優れる「ＬｉＭｅＯ２型」活物質が種々提案され、一部実用化されている。例えば、ＬｉＮｉ１／２Ｍｎ１／２Ｏ２やＬｉＣｏ１／３Ｎｉ１／３Ｍｎ１／３Ｏ２は、１５０〜１８０ｍＡｈ／ｇの放電容量を有する。 Accordingly, various “LiMeO 2 type” active materials having a Mn to Me molar ratio Mn / Me of 0.5 or less and excellent in charge / discharge cycle performance have been proposed and partially put into practical use. For example, LiNi 1/2 Mn 1/2 O 2 and LiCo 1/3 Ni 1/3 Mn 1/3 O 2 have a discharge capacity of 150 to 180 mAh / g.

近年、ＭｅとしてＮｉ，Ｃｏ及びＭｎを含み、Ｍｅに対するＭｎのモル比Ｍｎ／Ｍｅが０．５を超えるリチウム遷移金属複合酸化物を含有し、充電をしてもα−ＮａＦｅＯ２構造を維持できる正極活物質が提案された（特許文献１及び２参照）。 In recent years, Me contains Ni, Co, and Mn, and a molar ratio of Mn to Me, Mn / Me, containing a lithium transition metal composite oxide exceeding 0.5, can maintain an α-NaFeO 2 structure even when charged. A positive electrode active material has been proposed (see Patent Documents 1 and 2).

特許文献１及び２には、ＭｅとしてＮｉ，Ｃｏ及びＭｎを含み、Ｍｅに対するＭｎのモル比Ｍｎ／Ｍｅが０．５を超える正極活物質を用いた場合、４．３Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）を超え４．８Ｖ以下（ｖｓ．Ｌｉ／Ｌｉ＋）の正極電位範囲に出現する、電位変化が比較的平坦な領域に少なくとも至る充電を行う製造工程を設けることにより、使用時において、充電時の正極の最大到達電位が４．３Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）以下又は４．４Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）未満である充電方法が採用された場合であっても、２００ｍＡｈ／ｇ以上の放電容量が得られる電池を製造できることが記載されている。 In Patent Documents 1 and 2, when a positive electrode active material containing Ni, Co and Mn as Me and having a molar ratio Mn to Me of Mn / Me exceeding 0.5 is used, 4.3 V (vs. Li / Li + )) And 4.8V or less (vs. Li / Li + ), which appears in the positive electrode potential range, and is charged at the time of use by providing a manufacturing process for charging at least the region where the potential change is relatively flat. Even when a charging method in which the maximum potential of the positive electrode at the time is 4.3 V (vs. Li / Li + ) or less or less than 4.4 V (vs. Li / Li + ) is employed, 200 mAh / g It is described that a battery capable of obtaining the above discharge capacity can be manufactured.

このように、従来の「ＬｉＭｅＯ２型」正極活物質の場合とは異なり、ＭｅとしてＮｉ，Ｃｏ及びＭｎを含み、Ｍｅに対するＭｎのモル比Ｍｎ／Ｍｅが０．５を超える正極活物質では、少なくとも最初の充電において４．３Ｖを超える比較的高い電位、特に４．４Ｖ以上の電位に至って行うことにより、高い放電容量が得られるという特徴がある。
なお、この正極活物質は、遷移金属（Ｍｅ）の比率に対するリチウム（Ｌｉ）の組成比率Ｌｉ／Ｍｅが１より大きく、例えばＬｉ／Ｍｅが１．２５〜１．６であるように原料を混合して合成されることから、「リチウム過剰型」活物質とも呼ばれ、合成後の組成は理想的にＬｉ１＋αＭｅ１−αＯ２（α＞０）と表記できる。ここで、遷移金属（Ｍｅ）の比率に対するリチウム（Ｌｉ）の組成比率Ｌｉ／Ｍｅをβとすると、β＝（１＋α）／（１−α）であるから、例えば、Ｌｉ／Ｍｅが１．５のとき、α＝０．２である。 Thus, unlike the case of the conventional “LiMeO 2 type” positive electrode active material, in the positive electrode active material containing Ni, Co and Mn as Me and having a molar ratio of Mn to Me, Mn / Me exceeding 0.5, It is characterized in that a high discharge capacity can be obtained by performing a relatively high potential exceeding 4.3 V, particularly a potential of 4.4 V or higher, at least in the first charge.
In this positive electrode active material, the raw materials are mixed so that the composition ratio Li / Me of lithium (Li) with respect to the ratio of transition metal (Me) is larger than 1, for example, Li / Me is 1.25 to 1.6. Therefore, the composition after synthesis is ideally expressed as Li 1 + α Me 1-α O 2 (α> 0). Here, when the composition ratio Li / Me of lithium (Li) with respect to the ratio of the transition metal (Me) is β, β = (1 + α) / (1-α), and thus, for example, Li / Me is 1.5. In this case, α = 0.2.

特許文献２には、上記のような「リチウム過剰型」活物質を、炭酸塩前駆体を用いて作製した場合に、窒素ガス吸着法を用いた吸着等温線からＢＪＨ法で求めた微分細孔容積が最大値を示す細孔径が３０〜４０ｎｍの範囲で、ピーク微分細孔容積が０．７５ｍｍ３／（ｇ・ｎｍ）以上となることも記載されている（請求項３、段落［００３５］、［００４０］［０１１９］の表２）。 Patent Document 2 discloses a differential pore obtained by the BJH method from an adsorption isotherm using a nitrogen gas adsorption method when the above-described “lithium-excess type” active material is produced using a carbonate precursor. It is also described that the peak differential pore volume is 0.75 mm 3 / (g · nm) or more in a pore diameter range where the volume exhibits a maximum value of 30 to 40 nm (claim 3, paragraph [0035]). [0040] [0119] Table 2).

また、上記のような「ＬｉＭｅＯ２型」活物質と「リチウム過剰型」活物質とを混合して、正極活物質とすることも公知である（特許文献３〜５参照）。 It is also known to mix a “LiMeO 2 type” active material and a “lithium-excess type” active material as described above to obtain a positive electrode active material (see Patent Documents 3 to 5).

特許文献３には、「正極活物質を含む正極と、負極と、非水電解質とを備える非水電解質二次電池において、 前記正極活物質が、一般式ＬｉＣｏｘＭ１−ｘＯ２ (０．３≦ｘ≦０．７、Ｍは一種以上の遷移金属元素で少なくともＮｉ又はＭｎを含む)で表される第１活物質と、一般式Ｌｉ１＋ｙＭｎ１−ｙ−ｚＡｚＯ２（０＜ｙ＜０．４、０＜ｚ＜０．６、Ａは一種以上の遷移金属元素で少なくともＮｉ又はＣｏを含む)で表される第２活物質と、を含むことを特徴とする非水電解質二次電池。」（請求項１）、「前記第１活物質と前記第２活物質とを合わせた総質量に対する前記第１活物質の質量割合が、２０質量％〜８０質量％であることを特徴とする請求項１〜５のいずれか１項に記載の非水電解質二次電池。」（請求項６）、「前記第１活物質の平均粒径（Ｄ５０）及び前記第２活物質の平均粒径（Ｄ５０）のうち、大きい方をＲ、小さい方をｒとしたとき、０．２０＜ｒ／Ｒ＜０．６０が成り立つことを特徴とする請求項１〜６のいずれか１項に記載の非水電解質二次電池。」（請求項７）の発明が記載され、この発明の課題として、「リチウム過剰型遷移金属酸化物を有する正極活物質を正極に備えた非水電解質二次電池において、充放電サイクル特性を向上させる」こと（段落［０００５］）が記載されている。 Patent Document 3 discloses that, in a non-aqueous electrolyte secondary battery including a positive electrode including a positive electrode active material, a negative electrode, and a non-aqueous electrolyte, the positive electrode active material has a general formula LiCo x M 1-x O 2 (0 3 ≦ x ≦ 0.7, where M is one or more transition metal elements and includes at least Ni or Mn), and a general formula Li 1 + y Mn 1-yz A z O 2 ( A second active material represented by 0 <y <0.4, 0 <z <0.6, and A is one or more transition metal elements and includes at least Ni or Co). Water electrolyte secondary battery. "(Claim 1)," The mass ratio of the first active material to the total mass of the first active material and the second active material is 20 mass% to 80 mass%. The nonaqueous electrolyte secondary battery according to any one of claims 1 to 5, wherein the battery is a nonaqueous electrolyte secondary battery. Of average particle size of the first active material (D 50) and average particle diameter (D 50) of the second active material, when the larger the R, the smaller the r, 0.20 <r / R <0.60 is satisfied, The nonaqueous electrolyte secondary battery of any one of Claims 1-6 characterized by the above-mentioned. (Claim 7) invention is described, The subject of this invention is " “In a nonaqueous electrolyte secondary battery having a positive electrode active material having a lithium-excess type transition metal oxide in the positive electrode, charge / discharge cycle characteristics are improved” (paragraph [0005]).

また、特許文献３には、実施例として、水酸化物前駆体から作製した平均粒径（Ｄ５０）が１２μｍのＬｉＮｉ０．１５Ｃｏ０．７０Ｍｎ０．１５Ｏ２、ＬｉＣｏ０．５０Ｎｉ０．２５Ｍｎ０．２５Ｏ２、又はＬｉＣｏ１／３Ｎｉ１／３Ｍｎ１／３Ｏ２の第１活物質と、水酸化物前駆体から作製した平均粒径（Ｄ５０）が６μｍのＬｉ１．２Ｍｎ０．５４Ｎｉ０．１３Ｃｏ０．１３Ｏ２の第２活物質とを、質量比が５：５となるように混合して正極活物質とすること（段落［００１６］〜［００２３］）、平均粒径（Ｄ５０）が１４．１μｍのＬｉＣｏ１／３Ｎｉ１／３Ｍｎ１／３Ｏ２の第１活物質と、平均粒径（Ｄ５０）が１２．７μｍのＬｉ１．２Ｍｎ０．５４Ｎｉ０．１３Ｃｏ０．１３Ｏ２の第２活物質とを、質量比が８：２、６：４、４：６、又は２：８となるように混合して正極活物質とすること（段落［００３５］〜［００４２］、［００４６］表２）、平均粒径（Ｄ５０）が１４．１μｍのＬｉＣｏ１／３Ｎｉ１／３Ｍｎ１／３Ｏ２の第１活物質と、平均粒径（Ｄ５０）が６．３μｍのＬｉ１．２Ｍｎ０．５４Ｎｉ０．１３Ｃｏ０．１３Ｏ２の第２活物質とを、質量比が８：２となるように混合して正極活物質とすること（段落［００４８］〜［００５０］）が示されている。
さらに、「表３より、第１活物質の質量割合が同じである電極を比べた場合、０．２０＜ｒ／Ｒ＜０．６０の範囲で充填密度が大きくなることが分かる。」（段落［００５４］）と記載されている。 Patent Document 3 discloses, as an example, LiNi 0.15 Co 0.70 Mn 0.15 O 2 and LiCo 0.50 Ni having an average particle diameter (D 50 ) of 12 μm prepared from a hydroxide precursor. 0.25 Mn 0.25 O 2 or LiCo 1/3 Ni 1/3 Mn 1/3 O 2 first active material and the average particle size (D 50 ) produced from the hydroxide precursor is 6 μm Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 second active material is mixed so as to have a mass ratio of 5: 5 to obtain a positive electrode active material (paragraph [0016] to [0023]), and average particle diameter (D 50) is the first active material LiCo 1/3 Ni 1/3 Mn 1/3 O 2 of 14.1, an average particle diameter (D 50) 12.7μm of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 second O 2 The active material is mixed so that the mass ratio is 8: 2, 6: 4, 4: 6, or 2: 8 to obtain a positive electrode active material (paragraphs [0035] to [0042], [0046] Table 2), and an average particle diameter (D 50) the first active material LiCo 1/3 Ni 1/3 Mn 1/3 O 2 of 14.1, an average particle diameter (D 50) of 6.3 [mu] m Li 1.2 Mixing a second active material of Mn 0.54 Ni 0.13 Co 0.13 O 2 so as to have a mass ratio of 8: 2, to obtain a positive electrode active material (paragraphs [0048] to [0050]) is shown.
Furthermore, “From Table 3, it can be seen that when electrodes having the same mass ratio of the first active material are compared, the packing density increases in the range of 0.20 <r / R <0.60” (paragraph). [0054]).

特許文献４には、「Ｌｉ[Ｌｉ１／３Ｍｎ２／３]Ｏ２とＬｉＭ１Ｏ２（Ｍ１は１つ以上の遷移金属である）との固溶体であって、金属価数の合計が４である、固溶体と、ＬｉＭ２Ｏ２（Ｍ２は価数の合計が３である１つ以上の遷移金属である）で表される副活物質とが混合されてなる正極材料を正極活物質として含む、リチウムイオン電池用正極。」（請求項１）の発明が記載され、この発明の目的として、「高耐久性を保持しつつ、体積当りの容量密度が改善された、リチウムイオン電池用正極を提供すること」（段落［０００８］）が記載されている。 Patent Document 4, in "Li [Li 1/3 Mn 2/3] O 2 and LiM1O 2 (M1 is a is one or more transition metals) a solid solution of a total of 4 of the metal valence some, including a solid solution, the LiM2O 2 (M2 total valence is one or more transition metals is 3) positive electrode material and subsidiary active substance represented by is formed by mixing a positive electrode active material, lithium The positive electrode for an ion battery "(Claim 1) is described, and an object of the present invention is to provide a positive electrode for a lithium ion battery having an improved capacity density per volume while maintaining high durability. (Paragraph [0008]).

また、特許文献４には、実施例として、複合炭酸塩法を用いて調製したＬｉ２ＭｎＯ３―ＬｉＭ１Ｏ２系固溶体であるＬｉ[Ｎｉ０．１８３Ｌｉ０．２００Ｃｏ０．０３３Ｍｎ０．５８３]Ｏ２（０．６Ｌｉ[Ｌｉ１／３Ｍｎ２／３]Ｏ２・０．４Ｌｉ[Ｎｉ０．４５７５Ｃｏ０．０８２５Ｍｎ０．４５７５]Ｏ２）と、副活物質であるＬｉ[Ｎｉ１／３Ｃｏ１／３Ｍｎ１／３]Ｏ２」とを、固溶体組成：副活物質組成が質量％で９０：１０〜３０：７０となるように混合して正極活物質とすること（段落［００８１］〜［００８７］、［００９５］表１）が示されている。 Patent Document 4 discloses, as an example, Li [Ni 0.183 Li 0.200 Co 0.033 Mn 0.583, which is a Li 2 MnO 3 —LiM 1 O 2 -based solid solution prepared using a composite carbonate method. ] O 2 (0.6Li [Li 1/3 Mn 2/3 ] O 2 .0.4Li [Ni 0.4575 Co 0.0825 Mn 0.4575 ] O 2 ) and Li [Ni as a secondary active material 1/3 Co 1/3 Mn 1/3 ] O 2 ”is mixed so that the solid solution composition: by-active material composition is 90:10 to 30:70 by mass% to obtain a positive electrode active material ( Paragraphs [0081] to [0087], [0095] Table 1) are shown.

特許文献５には、「固溶体リチウム含有遷移金属酸化物Ａと、リチウム含有遷移金属酸化物Ｂとを含有する正極活物質であって、上記固溶体リチウム含有遷移金属酸化物Ａは、組成式（１） Ｌｉ１．５［ＮｉａＣｏｂＭｎｃ［Ｌｉ］ｄ］Ｏ３・・・で表され、・・・上記リチウム含有遷移金属酸化物Ｂは、組成式（２） Ｌｉ１．０Ｎｉａ・Ｃｏｂ・Ｍｎｃ・Ｏ２・・・で表され、・・・有することを特徴とする正極活物質。」（請求項１）の発明が記載され、この発明の目的として、「高い放電容量を維持しつつ、優れた放電作動電圧及び初期レート特性を実現し得る正極活物質、電気デバイス用正極及び電気デバイスを提供すること」（段落［０００８］）が記載されている。 Patent Document 5 states that “a positive electrode active material containing a solid solution lithium-containing transition metal oxide A and a lithium-containing transition metal oxide B, wherein the solid solution lithium-containing transition metal oxide A has a composition formula (1 ) Li 1.5 [Ni a Co b Mn c [Li] d ] O 3 ..., And the lithium-containing transition metal oxide B has a composition formula (2) Li 1.0 Ni a · Co b · Mn is represented by c · O 2 ·, the positive electrode active material and having .... "is described invention (claim 1), for the purpose of this invention," high discharge “Providing a positive electrode active material, a positive electrode for an electric device and an electric device capable of realizing excellent discharge operating voltage and initial rate characteristics while maintaining capacity” (paragraph [0008]) is described.

また、特許文献５には、実施例として、複合炭酸塩法を用いて合成した５０％通過粒径（Ｄ５０）が６．０μｍの固溶体リチウム含有遷移金属酸化物Ａ１であるＬｉ１．５[Ｎｉ０．４２Ｃｏ０．１５Ｍｎ０．７３[Ｌｉ]０．２０]Ｏ３又は５０％通過粒径（Ｄ５０）が５．９μｍの固溶体リチウム含有遷移金属酸化物Ａ２であるＬｉ１．５[Ｎｉ０．４３７５Ｃｏ０．１７５Ｍｎ０．７３７５[Ｌｉ]０．１５]Ｏ３と、水酸化物共沈法を用いて合成した５０％通過粒径（Ｄ５０）が１０．１μｍのリチウム含有遷移金属酸化物ＢであるＬｉ[Ｎｉ１／３Ｃｏ１／３Ｍｎ１／３]Ｏ２とを、Ａ１又はＡ２：Ｂが質量％で７５：２５〜２５：７５となるように混合して正極活物質とすること（段落［００９１］〜［００９６］、［０１０４］〜［０１１０］、［０１１４］表２）が示されている。 Patent Document 5 discloses, as an example, Li 1.5 [Ni, which is a solid solution lithium-containing transition metal oxide A1 having a 50% passing particle diameter (D50) of 6.0 μm synthesized by using a composite carbonate method. 0.42 Co 0.15 Mn 0.73 [Li] 0.20 ] O 3 or Li 1.5 [Ni] which is a solid solution lithium-containing transition metal oxide A2 having a 50% passing particle size (D50) of 5.9 μm 0.4375 Co 0.175 Mn 0.7375 [Li] 0.15 ] O 3 and a lithium-containing transition metal having a 50% passing particle size (D50) of 10.1 μm synthesized using a hydroxide coprecipitation method Li [Ni 1/3 Co 1/3 Mn 1/3 ] O 2 , which is an oxide B, is mixed so that A1 or A2: B is 75:25 to 25:75 by mass%, and the positive electrode active Substances (paragraphs [0091] to [0096], [01 4] to [0110], it has been shown [0114] Table 2).

ＷＯ２０１２／０９１０１５WO2012 / 091015 ＷＯ２０１３／０８４９２３WO2013 / 084923 特許第５３９４５７８号公報Japanese Patent No. 5394578 特開２０１２−５９５２７号公報JP 2012-59527 A 特開２０１３−１８７０２４号公報JP 2013-187024 A

上記のように、「リチウム過剰型」活物質と「ＬｉＭｅＯ２型」活物質の混合比率を変化させることにより、サイクル特性、容量密度、レート特性などを向上させる技術は公知であり、両者の粒子径が開示された文献もあるが、充填性を向上させることを課題として、両者の粒子径及び細孔径などの粉体物性を検討した公知技術は存在しない。
本発明は、上記課題に鑑みなされたものであって、「リチウム過剰型」活物質と「ＬｉＭｅＯ２型」活物質を混合して、リチウム二次電池の正極における単極電気化学特性と充填性（低多孔度）を両立させることができる混合活物質、その混合活物質を用いた正極、及び、その正極を備えたリチウム二次電池を提供することを課題とする。 As described above, a technique for improving cycle characteristics, capacity density, rate characteristics, and the like by changing the mixing ratio of the “lithium-excess type” active material and the “LiMeO 2 type” active material is known. Although there is a document in which the diameter is disclosed, there is no known technique in which powder properties such as the particle diameter and the pore diameter of the both are studied for the purpose of improving the filling property.
The present invention has been made in view of the above problems, and is a mixture of a “lithium-excess type” active material and a “LiMeO 2 type” active material, so that the unipolar electrochemical characteristics and fillability in the positive electrode of a lithium secondary battery are obtained. It is an object of the present invention to provide a mixed active material capable of achieving both (low porosity), a positive electrode using the mixed active material, and a lithium secondary battery including the positive electrode.

本発明においては、上記課題を解決するために、以下の手段を採用する。
（１）α−ＮａＦｅＯ２構造を有し、遷移金属Ｍｅ１としてＣｏ、Ｎｉ及びＭｎを含有し、１＜モル比Ｌｉ／Ｍｅ１＜１．５、モル比Ｍｎ／Ｍｅ１＞０．５であるリチウム遷移金属複合酸化物Ａと、組成式ＬｉＭｅ２Ｏ２（但し、Ｍｅ２はＣｏ、Ｎｉ及びＭｎを含む遷移金属、０＜モル比Ｍｎ／Ｍｅ２≦０．５）で表されるリチウム遷移金属複合酸化物Ｂの混合物を活物質とするリチウム二次電池用混合活物質であって、前記リチウム遷移金属複合酸化物Ａを前記混合物中に５０〜８５質量％含有し、前記リチウム遷移金属複合酸化物Ａは、平均粒子径が前記リチウム遷移金属複合酸化物Ｂの平均粒子径よりも小さく、かつ、窒素ガス吸着法を用いた吸着等温線からＢＪＨ法で求めた微分細孔容積が最大値を示す細孔径が３０〜４０ｎｍの範囲で、ピーク微分細孔容積が０．８５ｍｍ３／（ｇ・ｎｍ）以上であることを特徴とするリチウム二次電池用混合活物質。
（２）前記リチウム遷移金属複合酸化物Ａとして、粒子径が６μｍ以下の粒子を前記混合物中に４８〜８０質量％含有することを特徴とする前記（１）のリチウム二次電池用混合活物質。
（３）前記リチウム遷移金属複合酸化物Ａは、平均粒子径が８μｍ以下であることを特徴とする前記（１）又は（２）のリチウム二次電池用混合活物質。
（４）前記リチウム遷移金属複合酸化物Ｂは、平均粒子径が９μｍ以上であることを特徴とする前記（１）〜（３）のいずれか１項のリチウム二次電池用混合活物質。
（５）前記リチウム遷移金属複合酸化物Ｂとして、平均粒子径が１８μｍ以上の粒子を、前記混合物中に１０〜３０質量％含有することを特徴とする前記（１）〜（４）のいずれか１項のリチウム二次電池用混合活物質。
（６）前記リチウム遷移金属複合酸化物Ａは、組成式Ｌｉ１＋αＭｅ１１−αＯ２、１．１≦（１＋α）／（１−α）≦１．４で表されることを特徴とする前記（１）〜（５）のいずれか１項のリチウム二次電池用混合活物質。
（７）前記（１）〜（６）のいずれか１項のリチウム二次電池用混合活物質を含有するリチウム二次電池用正極。
（８）前記（７）のリチウム二次電池用正極を備えたリチウム二次電池。 In the present invention, in order to solve the above problems, the following means are adopted.
(1) Lithium transition having an α-NaFeO 2 structure, containing Co, Ni, and Mn as transition metals Me1, 1 <molar ratio Li / Me1 <1.5, and molar ratio Mn / Me1> 0.5 a metal composite oxide a, formula LiMe2O 2 (where, Me2 is Co, transition metal containing Ni and Mn, 0 <mole ratio Mn / Me2 ≦ 0.5) of the lithium transition metal complex oxide B represented by A mixed active material for a lithium secondary battery using a mixture as an active material, wherein the lithium transition metal composite oxide A is contained in an amount of 50 to 85% by mass in the mixture, and the lithium transition metal composite oxide A is an average The pore diameter of which the particle diameter is smaller than the average particle diameter of the lithium transition metal composite oxide B, and the differential pore volume obtained by the BJH method from the adsorption isotherm using the nitrogen gas adsorption method has a maximum value of 30. ~ 40nm In enclosed, mixed active material for a lithium secondary battery, characterized by a peak differential pore volume is 0.85mm 3 / (g · nm) or more.
(2) The mixed active material for a lithium secondary battery according to (1), wherein the lithium transition metal composite oxide A contains 48 to 80% by mass of particles having a particle size of 6 μm or less in the mixture. .
(3) The mixed active material for a lithium secondary battery according to (1) or (2), wherein the lithium transition metal composite oxide A has an average particle size of 8 μm or less.
(4) The mixed active material for a lithium secondary battery according to any one of (1) to (3), wherein the lithium transition metal composite oxide B has an average particle size of 9 μm or more.
(5) As said lithium transition metal complex oxide B, 10-30 mass% of particles with an average particle diameter of 18 micrometers or more are contained in the said mixture, Any one of said (1)-(4) characterized by the above-mentioned. Item 1. A mixed active material for a lithium secondary battery according to item 1.
(6) The lithium transition metal composite oxide A is represented by a composition formula Li 1 + α Me1 1-α O 2 , 1.1 ≦ (1 + α) / (1-α) ≦ 1.4. The mixed active material for a lithium secondary battery according to any one of (1) to (5).
(7) A positive electrode for a lithium secondary battery, comprising the mixed active material for a lithium secondary battery according to any one of (1) to (6).
(8) A lithium secondary battery comprising the positive electrode for a lithium secondary battery according to (7).

本発明によれば、「リチウム過剰型」活物質と「ＬｉＭｅＯ２型」活物質の混合に当たって、適切な混合比率、粒子径及び細孔容積を選択することにより、リチウム二次電池の正極における単極電気化学特性（高放電容量）と充填性（低多孔度）を両立させることができるという効果を奏する。 According to the present invention, in mixing the “lithium-excess” type active material and the “LiMeO 2 type” active material, by selecting an appropriate mixing ratio, particle diameter and pore volume, a single unit in the positive electrode of the lithium secondary battery is obtained. There is an effect that it is possible to achieve both polar electrochemical characteristics (high discharge capacity) and filling properties (low porosity).

本発明に係るリチウム二次電池の一実施形態を示す外観斜視図1 is an external perspective view showing an embodiment of a lithium secondary battery according to the present invention. 本発明に係るリチウム二次電池を複数個集合した蓄電装置を示す概略図Schematic showing a power storage device in which a plurality of lithium secondary batteries according to the present invention are assembled

本発明に係るリチウム二次電池用混合活物質が含有するリチウム遷移金属複合酸化物Ａは、高い放電容量を得るために、遷移金属Ｍｅ１に対するリチウム（Ｌｉ）のモル比Ｌｉ／Ｍｅ１を１より大きい、リチウム過剰型リチウム遷移金属複合酸化物とする。この特徴は、典型的には、組成式Ｌｉ１＋αＭｅ１１−αＯ２において、（１＋α）／（１−α）＞１、すなわち、α＞０と表記することができる。 In order to obtain a high discharge capacity, the lithium transition metal composite oxide A contained in the mixed active material for a lithium secondary battery according to the present invention has a molar ratio Li / Me1 of lithium (Li) to the transition metal Me1 of greater than 1. And a lithium-excess type lithium transition metal composite oxide. Typically, this feature can be expressed as (1 + α) / (1-α)> 1, that is, α> 0 in the composition formula Li 1 + α Me1 1-α O 2 .

本発明においては、混合活物質におけるリチウム過剰型リチウム遷移金属複合酸化物Ａの遷移金属Ｍｅ１に対するＬｉのモル比Ｌｉ／Ｍｅ１を、１より大きく且つ１．５より小さくとすることにより、放電容量が大きく、且つ、正極が低多孔度のリチウム二次電池を得ることができる。
なかでも、放電容量が大きいリチウム二次電池を得るために、遷移金属Ｍｅ１に対するＬｉのモル比Ｌｉ／Ｍｅ１は、１．１以上で且つ１．５より小さくとすること、すなわち、組成式Ｌｉ１＋αＭｅ１１−αＯ２において１．１≦（１＋α）／（１−α）＜１．５とすることが好ましい。特に、放電容量が大きく、高率放電性能が優れたリチウム二次電池を得ることができるという観点から、前記Ｌｉ／Ｍｅ１が１．１５〜１．４のものを選択することが好ましく、１．２〜１．４のものがより好ましい。 In the present invention, by setting the molar ratio Li / Me1 of Li to the transition metal Me1 of the lithium-excess type lithium transition metal composite oxide A in the mixed active material to be larger than 1 and smaller than 1.5, the discharge capacity is increased. A lithium secondary battery having a large positive electrode and a low porosity can be obtained.
In particular, in order to obtain a lithium secondary battery having a large discharge capacity, the molar ratio Li / Me1 of Li to the transition metal Me1 should be 1.1 or more and less than 1.5, that is, the composition formula Li 1 + α In Me1 1-α O 2 , it is preferable that 1.1 ≦ (1 + α) / (1−α) <1.5. In particular, from the viewpoint that a lithium secondary battery having a large discharge capacity and excellent high-rate discharge performance can be obtained, it is preferable to select a Li / Me1 of 1.15 to 1.4. The thing of 2-1.4 is more preferable.

リチウム過剰型リチウム遷移金属複合酸化物Ａの組成は、高い放電容量が得られる点から、遷移金属Ｍｅ１がＣｏ、Ｎｉ及びＭｎを含み、モル比Ｍｎ／Ｍｅ１＞０．５である。モル比Ｍｎ／Ｍｅ１は０．６以上が好ましく、０．６〜０．７５がより好ましい。   The composition of the lithium-excess type lithium transition metal composite oxide A is such that the transition metal Me1 contains Co, Ni and Mn, and the molar ratio Mn / Me1> 0.5 from the viewpoint that a high discharge capacity is obtained. The molar ratio Mn / Me1 is preferably 0.6 or more, and more preferably 0.6 to 0.75.

また、リチウム二次電池の初期効率及び高率放電性能を向上させるために、遷移金属元素Ｍｅ１に対するＣｏのモル比Ｃｏ／Ｍｅ１は、０．０５〜０．４０とすることが好ましく、０．１０〜０．３０とすることがより好ましい。   In order to improve the initial efficiency and high rate discharge performance of the lithium secondary battery, the molar ratio Co / Me1 of Co to the transition metal element Me1 is preferably 0.05 to 0.40, and 0.10. More preferably, it is set to ˜0.30.

本発明に係るリチウム遷移金属複合酸化物Ａは、典型例として、一般式Ｌｉ１＋α（ＣｏａＮｉｂＭｎｃ）１−αＯ２、但し、（１＋α）／（１−α）＞１、ａ＋ｂ＋ｃ＝１、ａ＞０、ｂ＞０、ｃ＞０で表わされるものであり、本質的に、Ｌｉ、Ｃｏ、Ｎｉ及びＭｎからなる複合酸化物である。例えば、Ｌｉ１．１３Ｃｏ０．１１Ｎｉ０．１７Ｍｎ０．５９Ｏ２（Ｌｉ／Ｍｅ＝１．３、Ｍｎ／Ｍｅ＝０．６８）、Ｌｉ１．１１Ｃｏ０．１１Ｎｉ０．１８Ｍｎ０．６０Ｏ２（Ｌｉ／Ｍｅ＝１．２５、Ｍｎ／Ｍｅ＝０．６７）、Ｌｉ１．１５Ｃｏ０．１１Ｎｉ０．１７Ｍｎ０．５７Ｏ２（Ｌｉ／Ｍｅ＝１．３５、Ｍｎ／Ｍｅ＝０．６７）、Ｌｉ１．１７Ｃｏ０．１１Ｎｉ０．１６Ｍｎ０．５６Ｏ２（Ｌｉ／Ｍｅ＝１．４、Ｍｎ／Ｍｅ＝０．６７）、Ｌｉ１．０５Ｃｏ０．１２Ｎｉ０．１９Ｍｎ０．６４Ｏ２（Ｌｉ／Ｍｅ＝１．１、Ｍｎ／Ｍｅ＝０．６７）、Ｌｉ１．０７Ｃｏ０．１２Ｎｉ０．１８Ｍｎ０．６３Ｏ２（Ｌｉ／Ｍｅ＝１．１５、Ｍｎ／Ｍｅ＝０．６８）、Ｌｉ１．０９Ｃｏ０．１１Ｎｉ０．１８Ｍｎ０．６２Ｏ２（Ｌｉ／Ｍｅ＝１．２、Ｍｎ／Ｍｅ＝０．６８）等の複合酸化物であるが、放電容量を向上させるために、Ｎａを１０００ｐｐｍ以上含ませることが好ましい。Ｎａの含有量は、２０００〜１００００ｐｐｍがより好ましい。 The lithium transition metal composite oxide A according to the present invention typically has a general formula Li 1 + α (Co a Ni b Mn c ) 1-α O 2 , where (1 + α) / (1-α)> 1, a + b + c = 1, a> 0, b> 0, c> 0, and is essentially a composite oxide composed of Li, Co, Ni, and Mn. For example, Li 1.13 Co 0.11 Ni 0.17 Mn 0.59 O 2 (Li / Me = 1.3, Mn / Me = 0.68), Li 1.11 Co 0.11 Ni 0.18 Mn 0.60 O 2 (Li / Me = 1.25, Mn / Me = 0.67), Li 1.15 Co 0.11 Ni 0.17 Mn 0.57 O 2 (Li / Me = 1.35) , Mn / Me = 0.67), Li 1.17 Co 0.11 Ni 0.16 Mn 0.56 O 2 (Li / Me = 1.4, Mn / Me = 0.67), Li 1.05 Co 0.12 Ni 0.19 Mn 0.64 O 2 (Li / Me = 1.1, Mn / Me = 0.67), Li 1.07 Co 0.12 Ni 0.18 Mn 0.63 O 2 (Li / Me = 1.15, Mn / Me = 0.68), Li 1.09 Co 0.1 Ni 0.18 Mn 0.62 O 2 (Li / Me = 1.2, Mn / Me = 0.68) is a composite oxide such as, in order to improve the discharge capacity, the inclusion of Na or 1000ppm It is preferable. As for content of Na, 2000-10000 ppm is more preferable.

Ｎａを含有させるために、後述する炭酸塩前駆体を作製する工程において、炭酸ナトリウム等のナトリウム化合物を中和剤として使用し、洗浄工程でＮａを残存させるか、及び、その後の焼成工程において炭酸ナトリウム等のナトリウム化合物を添加する方法を採用することができる。   In order to contain Na, in the step of preparing a carbonate precursor, which will be described later, a sodium compound such as sodium carbonate is used as a neutralizing agent, and Na is left in the washing step. A method of adding a sodium compound such as sodium can be employed.

また、本発明の効果を損なわない範囲で、Ｎａ以外のアルカリ金属、Ｍｇ，Ｃａ等のアルカリ土類金属、Ｆｅ，Ｚｎ等の３ｄ遷移金属に代表される遷移金属など少量の他の金属を含有することを排除するものではない。   In addition, a small amount of other metals such as alkali metals other than Na, alkaline earth metals such as Mg and Ca, transition metals typified by 3d transition metals such as Fe and Zn, etc. are contained within the range not impairing the effects of the present invention It does not exclude doing.

本発明に係るリチウム過剰型リチウム遷移金属複合酸化物Ａは、α−ＮａＦｅＯ２構造を有している。合成後（充放電を行う前）の上記リチウム遷移金属複合酸化物は、空間群Ｐ３１１２あるいはＲ３−ｍに帰属される。このうち、空間群Ｐ３１１２に帰属されるものには、ＣｕＫα管球を用いたエックス線回折図上、２θ＝２１°付近に超格子ピーク（Ｌｉ［Ｌｉ１／３Ｍｎ２／３］Ｏ２型の単斜晶に見られるピーク）が確認される。ところが、一度でも充電を行い、結晶中のＬｉが脱離すると結晶の対称性が変化することにより、上記超格子ピークが消滅して、上記リチウム遷移金属複合酸化物は空間群Ｒ３−ｍに帰属されるようになる。ここで、Ｐ３１１２は、Ｒ３−ｍにおける３ａ、３ｂ、６ｃサイトの原子位置を細分化した結晶構造モデルであり、Ｒ３−ｍにおける原子配置に秩序性が認められるときに該Ｐ３１１２モデルが採用される。なお、「Ｒ３−ｍ」は本来「Ｒ３ｍ」の「３」の上にバー「−」を施して表記すべきものである。 The lithium-rich lithium transition metal composite oxide A according to the present invention has an α-NaFeO 2 structure. The lithium transition metal composite oxide after synthesis (before charging and discharging) is attributed to the space group P3 1 12 or R3-m. Among these, those belonging to the space group P3 1 12 are superlattice peaks (Li [Li 1/3 Mn 2/3 ] O 2 near 2θ = 21 ° on the X-ray diffraction diagram using the CuKα tube. The peak observed in the monoclinic type) is confirmed. However, when charging is performed once and Li in the crystal is desorbed, the symmetry of the crystal changes, whereby the superlattice peak disappears and the lithium transition metal composite oxide belongs to the space group R3-m. Will come to be. Here, P3 1 12 is a crystal structure model in which the atomic positions of the 3a, 3b, and 6c sites in R3-m are subdivided, and when ordering is recognized in the atomic arrangement in R3-m, the P3 1 12 model Is adopted. Note that “R3-m” should be represented by adding a bar “-” on “3” of “R3m”.

また、リチウム過剰型リチウム遷移金属複合酸化物Ａは、ＣｕＫα線源を用いたエックス線回折パターンにおける２θ＝４４±１°の回折ピークの半値幅を０．２６５°以上とすることが好ましい。これにより、正極活物質の高率放電性能を向上させることが可能となる。２θ＝４４±１°の回折ピークの半値幅の上限は限定されるものではないが、０．２８５程度までとすることができる。なお、２θ＝４４±１°の回折ピークは、空間群Ｐ３１１２では（１１４）面、空間群Ｒ３−ｍでは（１０４）面にそれぞれ指数付けされる。 Further, in the lithium-excess type lithium transition metal composite oxide A, the half width of the diffraction peak at 2θ = 44 ± 1 ° in the X-ray diffraction pattern using the CuKα ray source is preferably 0.265 ° or more. Thereby, it is possible to improve the high rate discharge performance of the positive electrode active material. The upper limit of the half width of the diffraction peak at 2θ = 44 ± 1 ° is not limited, but can be up to about 0.285. The diffraction peak at 2θ = 44 ± 1 ° is indexed on the (114) plane in the space group P3 1 12 and on the (104) plane in the space group R3-m.

さらに、リチウム過剰型リチウム遷移金属複合酸化物Ａは、エックス線回折パターンを基にリートベルト法による結晶構造解析から求められる酸素位置パラメータが、放電末において０．２６２以下、充電末において０．２６７以上であることが好ましい。これにより、高率放電性能が優れたリチウム二次電池を得ることができる。なお、酸素位置パラメータとは、空間群Ｒ３−ｍに帰属されるリチウム遷移金属複合酸化物のα―ＮａＦｅＯ２型結晶構造について、Ｍｅ（遷移金属）の空間座標を(０，０，０)、Ｌｉ（リチウム）の空間座標を(０，０，１／２)、Ｏ（酸素）の空間座標を(０，０，ｚ)と定義したときの、ｚの値をいう。即ち、酸素位置パラメータは、Ｏ（酸素）位置がＭｅ（遷移金属）位置からどれだけ離れているかを示す相対的な指標となる（特許文献１及び２参照）。 Further, in the lithium-excess type lithium transition metal composite oxide A, the oxygen position parameter obtained from the crystal structure analysis by the Rietveld method based on the X-ray diffraction pattern is 0.262 or less at the end of discharge and 0.267 or more at the end of charge. It is preferable that Thereby, a lithium secondary battery excellent in high rate discharge performance can be obtained. Note that the oxygen positional parameter is Me (transition metal) spatial coordinates (0, 0, 0) for the α-NaFeO 2 type crystal structure of the lithium transition metal composite oxide belonging to the space group R3-m, This is the value of z when the spatial coordinates of Li (lithium) are defined as (0, 0, 1/2) and the spatial coordinates of O (oxygen) are defined as (0, 0, z). In other words, the oxygen position parameter is a relative index indicating how far the O (oxygen) position is from the Me (transition metal) position (see Patent Documents 1 and 2).

本発明においては、リチウム二次電池の正極における単極電気化学特性と充填性（低多孔度）を両立させるために、リチウム過剰型リチウム遷移金属複合酸化物Ａとして、窒素ガス吸着法を用いた吸着等温線からＢＪＨ法で求めた微分細孔容積が最大値を示す細孔径が３０〜４０ｎｍの範囲で、ピーク微分細孔容積が０．８５ｍｍ３／（ｇ・ｎｍ）以上のものを採用する。１．０ｍｍ３／（ｇ・ｎｍ）以上のものが好ましい。０．８５ｍｍ３／（ｇ・ｎｍ）未満では、正極における単極電気化学特性が低下し、後述するように、リチウム二次電池の放電容量が低下する。上限は、特に限定されないが、３．０ｍｍ３／（ｇ・ｎｍ）程度とすることができる。
ピーク微分細孔容積が大きいリチウム過剰型リチウム遷移金属複合酸化物は、後述する炭酸塩前駆体から作製することができる。 In the present invention, a nitrogen gas adsorption method was used as the lithium-excess lithium transition metal composite oxide A in order to achieve both monopolar electrochemical characteristics and filling properties (low porosity) in the positive electrode of the lithium secondary battery. A differential pore volume having a peak differential pore volume of 0.85 mm 3 / (g · nm) or more in a range of 30 to 40 nm in which the differential pore volume obtained by the BJH method from the adsorption isotherm exhibits a maximum value is employed. . The thing of 1.0 mm < 3 > / (g * nm) or more is preferable. If it is less than 0.85 mm < 3 > / (g * nm), the single electrode electrochemical characteristic in a positive electrode will fall, and the discharge capacity of a lithium secondary battery will fall so that it may mention later. Although an upper limit is not specifically limited, It can be set as about 3.0 mm < 3 > / (g * nm).
The lithium-excess type lithium transition metal composite oxide having a large peak differential pore volume can be prepared from a carbonate precursor described later.

次に、本発明に係るリチウム二次電池用混合活物質が含有するリチウム遷移金属複合酸化物Ｂ、いわゆるＬｉＭｅＯ２型リチウム遷移金属複合酸化物については、周知のものを用いることができる。典型例は、組成式ＬｉＭｅ２Ｏ２（但し、Ｍｅ２はＣｏ、Ｎｉ及びＭｎを含む遷移金属、０＜モル比Ｍｎ／Ｍｅ２≦０．５）で表される。その一例はＬｉＣｏ１／３Ｎｉ１／３Ｍｎ１／３Ｏ２であるが、Ｃｏ、Ｎｉ、Ｍｎの塩の混合溶液をアルカリ溶液中に滴下し、共沈水酸化物を作製し、それをＬｉ塩と混合・焼成するなどの方法により製造することができる。Ｃｏ、Ｎｉ、Ｍｎの比率を変更したＬｉＣｏ２／３Ｎｉ１／６Ｍｎ１／６Ｏ２、ＬｉＣｏ０．３Ｎｉ０．５Ｍｎ０．２Ｏ２等を用いることもできる。
また、リチウム過剰型リチウム遷移金属複合酸化物は、結晶構造的に、Ｌｉサイトだけでなく遷移金属サイトにＬｉが位置しているのに対し、ＬｉＭｅＯ２型リチウム遷移金属複合酸化物は、ＬｉがＬｉサイトに専ら位置しているから、理論的にＬｉ／Ｍｅ＝１である。ただし、ＬｉＭｅＯ２は、合成時のＬｉ原料の仕込み量をＬｉ／Ｍｅ＞１とするといった工程を経た場合、定量分析学的にはＬｉ／Ｍｅ＞１となることがあり、また、電気化学的に酸化（充電）させた場合、定量分析学的にはＬｉ／Ｍｅ＜１となることがある。しかしながら、ＬｉＭｅ２Ｏ２で表されるリチウム遷移金属複合酸化物Ｂは、Ｌｉ／Ｍｅ２が１と等しくない場合であっても、実質的にリチウム過剰型リチウム遷移金属複合酸化物ＡのようにＬｉの一部が遷移金属サイトに位置するものではないから、リチウム過剰型リチウム遷移金属複合酸化物Ａとは区別できる。 Next, the lithium transition metal complex oxide B mixed active material for a lithium secondary battery according to the present invention contains, so-called LiMeO 2 type lithium transition metal composite oxide can be used those known. Typical examples are the composition formula LiMe2O 2 (where, Me2 is Co, transition metal containing Ni and Mn, 0 <mole ratio Mn / Me2 ≦ 0.5) is represented by. One example is LiCo 1/3 Ni 1/3 Mn 1/3 O 2 , but a mixed solution of a salt of Co, Ni, and Mn is dropped into an alkaline solution to produce a coprecipitated hydroxide, which is Li It can be produced by a method such as mixing with salt and baking. LiCo 2/3 Ni 1/6 Mn 1/6 O 2 , LiCo 0.3 Ni 0.5 Mn 0.2 O 2 or the like in which the ratio of Co, Ni, and Mn is changed can also be used.
The lithium-excess type lithium transition metal composite oxide has a crystal structure in which Li is located not only at the Li site but also at the transition metal site, whereas the LiMeO 2 type lithium transition metal composite oxide has a Li content. Since it is exclusively located at the Li site, theoretically Li / Me = 1. However, LiMeO 2 may be Li / Me> 1 in terms of quantitative analysis when it is subjected to a process such that the amount of Li raw material charged during synthesis is Li / Me> 1. When it is oxidized (charged), Li / Me <1 in some quantitative analysis. However, the lithium transition metal complex oxide B represented by LiMe2O 2, even if Li / Me2 is not equal to 1, the Li substantially as lithium-rich lithium transition metal complex oxide A one Since the portion is not located at the transition metal site, it can be distinguished from the lithium-rich lithium transition metal composite oxide A.

本発明においては、リチウム二次電池の正極における単極電気化学特性と充填性（低多孔度）を両立させるために、前記リチウム過剰型リチウム遷移金属複合酸化物Ａと前記ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂを混合した混合活物質を正極活物質とする。前記リチウム過剰型リチウム遷移金属複合酸化物Ａを混合活物質中に５０〜８５質量％含有させる。５０質量％未満では、リチウム二次電池の放電容量が低下する。８５％を超えると、正極の限界多孔度（電極合剤ペーストの塗布量は一定とし、プレス圧を順次大きくすることによって多孔度の小さい電極を順次作成し、電極を湾曲させても合剤層が折れることがない最小の多孔度）が大きくなる。放電容量を向上させ、かつ、正極の充填性（低多孔度）を改善するためには、即ち、正極の限界多孔度を小さくするためには、前記リチウム過剰型リチウム遷移金属複合酸化物Ａを混合活物質中に５０〜８０質量％含有させることが好ましく、６０〜８０質量％含有させることがより好ましい。 In the present invention, the lithium-excess type lithium transition metal composite oxide A and the LiMeO 2 type lithium transition metal are used in order to achieve both monopolar electrochemical characteristics and filling properties (low porosity) in the positive electrode of the lithium secondary battery. A mixed active material in which the composite oxide B is mixed is defined as a positive electrode active material. The lithium-excess type lithium transition metal composite oxide A is contained in an amount of 50 to 85% by mass in the mixed active material. If it is less than 50% by mass, the discharge capacity of the lithium secondary battery is lowered. If it exceeds 85%, the critical porosity of the positive electrode (the coating amount of the electrode mixture paste is kept constant, and the electrode layer is formed even if the electrodes are curved by successively increasing the press pressure and bending the electrodes. The minimum porosity that does not break). In order to improve the discharge capacity and improve the filling property (low porosity) of the positive electrode, that is, to reduce the critical porosity of the positive electrode, the lithium-excess type lithium transition metal composite oxide A is used. It is preferable to contain 50-80 mass% in a mixed active material, and it is more preferable to make it contain 60-80 mass%.

本発明に係るリチウム二次電池用混合活物質においては、前記リチウム過剰型リチウム遷移金属複合酸化物Ａの平均粒子径を、前記ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂの平均粒子径よりも小さくする。後述する比較例のように、粒径の異なるリチウム遷移金属複合酸化物を混合した混合活物質であっても、リチウム過剰型リチウム遷移金属複合酸化物Ａの平均粒子径が、ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂの平均粒子径よりも大きい場合、充填性（低多孔度）は改善されない。 In the mixed active material for a lithium secondary battery according to the present invention, the average particle size of the lithium-excess type lithium transition metal composite oxide A is smaller than the average particle size of the LiMeO 2 type lithium transition metal composite oxide B. To do. Even in the case of a mixed active material in which lithium transition metal composite oxides having different particle diameters are mixed as in the comparative example described later, the average particle diameter of the lithium-excess lithium transition metal composite oxide A is LiMeO 2 type lithium transition. When larger than the average particle diameter of the metal composite oxide B, the filling property (low porosity) is not improved.

前記リチウム過剰型リチウム遷移金属複合酸化物Ａは、小粒径であるほど単極電気化学特性が優れる（リチウム二次電池の放電容量が向上する）ため、粒子径が６μｍ以下のリチウム遷移金属複合酸化物Ａの含有量を、混合物中の４８〜８５質量％とすることが好ましく、４８〜８０質量％とすることがより好ましい。粒子径が６μｍを超え、１８μｍ未満である中粒径のリチウム遷移金属複合酸化物Ａを含有させることもできる。例えば、平均粒子径が８〜１４μｍ、好ましくは１０〜１２μｍである中粒径のリチウム遷移金属複合酸化物Ａを１０〜２０質量％含有させることもできる。例えば、後述する実施例のように、混合活物質中に、平均粒子径（Ｄ５０）が４μｍのリチウム過剰型リチウム遷移金属複合酸化物Ａを４８質量％、１２μｍのリチウム過剰型リチウム遷移金属複合酸化物Ａを２０質量％含有させた場合、そのＤ５０は６．７５μｍとなる。また、混合活物質中に、平均粒子径（Ｄ５０）が６μｍのリチウム過剰型リチウム遷移金属複合酸化物Ａを５０質量％、１２μｍのリチウム過剰型リチウム遷移金属複合酸化物Ａを２０質量％含有させた場合、そのＤ５０は７．７μｍとなる。したがって、リチウム過剰型リチウム遷移金属複合酸化物Ａの平均粒子径（Ｄ５０）は、８μｍ以下とすることが好ましい。６μｍ以下の小粒径のリチウム遷移金属複合酸化物Ａの下限は限定されるものではないが、その平均粒子径（Ｄ５０）を２μｍ以上とすることができる。 The lithium-excess type lithium transition metal composite oxide A has a monopolar electrochemical characteristic that is smaller as the particle size is smaller (the discharge capacity of the lithium secondary battery is improved). Therefore, the lithium transition metal composite having a particle diameter of 6 μm or less. The content of the oxide A is preferably 48 to 85% by mass in the mixture, and more preferably 48 to 80% by mass. A medium-sized lithium transition metal composite oxide A having a particle diameter of more than 6 μm and less than 18 μm can also be contained. For example, 10 to 20% by mass of a medium-sized lithium transition metal composite oxide A having an average particle size of 8 to 14 μm, preferably 10 to 12 μm may be contained. For example, as in the examples described later, 48% by mass of lithium-excess type lithium transition metal composite oxide A having an average particle diameter (D 50 ) of 4 μm and 12 μm of lithium-excess type lithium transition metal composite in the mixed active material when the oxide a is contained 20 mass%, its D 50 is the 6.75Myuemu. The mixed active material contains 50% by mass of lithium-excess type lithium transition metal composite oxide A having an average particle size (D 50 ) of 6 μm and 20% by mass of 12 μm of lithium-excess type lithium transition metal composite oxide A. In this case, the D 50 is 7.7 μm. Therefore, the average particle size (D 50 ) of the lithium-excess type lithium transition metal composite oxide A is preferably 8 μm or less. The lower limit of the lithium transition metal composite oxide A having a small particle diameter of 6 μm or less is not limited, but the average particle diameter (D 50 ) can be 2 μm or more.

前記ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂは、充填性（低多孔度）を改善するために、平均粒子径（Ｄ５０）が９μｍ以上の中粒径及び／又は大粒径とすることが好ましい。粒子径が６μｍを超え、１８μｍ未満である中粒径のリチウム遷移金属複合酸化物Ｂを含有させることもできる。例えば、平均粒子径（Ｄ５０）が８〜１４μｍ、好ましくは１０〜１２μｍである中粒径のリチウム遷移金属複合酸化物Ｂを５〜５０質量％、好ましくは１０〜３０質量％含有させることができる。粒子径が１８μｍ以上である大粒径のＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂを前記混合活物質中に１０〜３０質量％含有させることにより、充填性（低多孔度）が顕著に改善される。粒子径が６μｍ以下のリチウム遷移金属複合酸化物Ｂを含有させることもできる。例えば、後述する実施例のように、混合活物質中に、平均粒子径（Ｄ５０）が４μｍのＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂを１２質量％、１８μｍのＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂを２０質量％含有させた場合、そのＤ５０は９μｍとなる。したがって、ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂの平均粒子径（Ｄ５０）は、９μｍ以上とすることが好ましい。１８μｍ以上の大粒径のＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂの上限は限定されるものではないが、その平均粒子径（Ｄ５０）を２５μｍ以下とすることができる。 The LiMeO 2 type lithium transition metal composite oxide B may have an average particle diameter (D 50 ) of 9 μm or more and / or a large particle diameter in order to improve the filling property (low porosity). preferable. A medium-sized lithium transition metal composite oxide B having a particle diameter of more than 6 μm and less than 18 μm can also be contained. For example, 5 to 50% by mass, preferably 10 to 30% by mass of the medium-sized lithium transition metal composite oxide B having an average particle size (D 50 ) of 8 to 14 μm, preferably 10 to 12 μm. it can. By containing 10 to 30% by mass of LiMeO 2 type lithium transition metal composite oxide B having a large particle diameter of 18 μm or more in the mixed active material, the filling property (low porosity) is remarkably improved. The A lithium transition metal composite oxide B having a particle size of 6 μm or less can also be contained. For example, as in Examples described later, 12% by mass of LiMeO 2 type lithium transition metal composite oxide B having an average particle diameter (D 50 ) of 4 μm and 18 μm of LiMeO 2 type lithium transition metal composite in the mixed active material. When 20 mass% of oxide B is contained, the D 50 is 9 μm. Therefore, the average particle diameter (D 50 ) of the LiMeO 2 type lithium transition metal composite oxide B is preferably 9 μm or more. The upper limit of the LiMeO 2 type lithium transition metal composite oxide B having a large particle size of 18 μm or more is not limited, but the average particle size (D 50 ) can be 25 μm or less.

本発明においては、小粒径、又は小粒径及び中粒径の活物質としてリチウム過剰型リチウム遷移金属複合酸化物Ａを５０〜８５質量％用いることで放電容量を確保すると共に、中粒径及び／又は大粒径の活物質であるＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂを混合し、粒径分布が山なり（なだらかな凸状）になるよう設計し、正極の限界多孔度を小さくすることができる。
放電容量を向上させると共に、正極の限界多孔度を特に小さくするためには、粒子径が６μｍ以下である小粒径のリチウム遷移金属複合酸化物Ａの含有量を、両者の混合物中の４８〜８５質量％とし、粒子径が６μｍを超え、１８μｍ未満である中粒径のリチウム過剰型リチウム遷移金属複合酸化物Ａ及び／又はＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂを含有させ、かつ、粒子径が１８μｍ以上である大粒径のＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂの含有量を、両者の混合物中の１０〜３０質量％とすることが好ましい。 In the present invention, the discharge capacity is ensured by using 50 to 85% by mass of the lithium-excess type lithium transition metal composite oxide A as an active material having a small particle size, or a small particle size and a medium particle size, and a medium particle size. And / or LiMeO 2 type lithium transition metal composite oxide B, which is an active material having a large particle size, is mixed and designed to have a gradual particle size distribution (smooth convex shape), thereby reducing the critical porosity of the positive electrode. can do.
In order to improve the discharge capacity and particularly reduce the critical porosity of the positive electrode, the content of the small-sized lithium transition metal composite oxide A having a particle size of 6 μm or less is set to 48 to 48 in the mixture of both. 85% by mass, medium-sized lithium-excess lithium transition metal composite oxide A and / or LiMeO 2 type lithium transition metal composite oxide B having a particle diameter of more than 6 μm and less than 18 μm, and particles The content of the LiMeO 2 type lithium transition metal composite oxide B having a large particle diameter of 18 μm or more is preferably 10 to 30% by mass in the mixture of both.

次に、本発明のリチウム過剰型リチウム遷移金属複合酸化物Ａを製造する方法について説明する。
本発明のリチウム過剰型リチウム遷移金属複合酸化物Ａは、基本的に、活物質を構成する金属元素（Ｌｉ，Ｍｎ，Ｃｏ，Ｎｉ）を目的とする活物質（酸化物）の組成通りに含有する原料を調整し、これを焼成することによって得ることができる。但し、Ｌｉ原料の量については、焼成中にＬｉ原料の一部が消失することを見込んで、１〜５％程度過剰に仕込むことが好ましい。 Next, a method for producing the lithium-excess type lithium transition metal composite oxide A of the present invention will be described.
The lithium-excess type lithium transition metal composite oxide A of the present invention basically contains a metal element (Li, Mn, Co, Ni) constituting the active material in accordance with the composition of the active material (oxide) for the purpose. It can be obtained by adjusting the raw material to be prepared and firing it. However, with respect to the amount of the Li raw material, it is preferable to add an excess of about 1 to 5% in view of the disappearance of a part of the Li raw material during firing.

目的とする組成の酸化物を作製するにあたり、Ｌｉ，Ｃｏ，Ｎｉ，Ｍｎのそれぞれの塩を混合・焼成するいわゆる「固相法」や、あらかじめＣｏ，Ｎｉ，Ｍｎを一粒子中に存在させた共沈前駆体を作製しておき、これにＬｉ塩を混合・焼成する「共沈法」が知られている。「固相法」による合成過程では、特にＭｎはＣｏ，Ｎｉに対して均一に固溶しにくいため、各元素が一粒子中に均一に分布した試料を得ることは困難である。これまで文献などにおいては固相法によってＮｉやＣｏの一部にＭｎを固溶（ＬｉＮｉ１−ｘＭｎｘＯ２など）しようという試みが多数なされているが、「共沈法」を選択する方が原子レベルで均一相を得ることが容易である。そこで、後述する実施例においては、「共沈法」を採用した。 In producing an oxide having a desired composition, a so-called “solid phase method” in which salts of Li, Co, Ni, and Mn are mixed and fired, or Co, Ni, and Mn were previously present in one particle. A “coprecipitation method” is known in which a coprecipitation precursor is prepared, and a Li salt is mixed and fired therein. In the synthesis process by the “solid phase method”, especially Mn is difficult to uniformly dissolve in Co and Ni, so it is difficult to obtain a sample in which each element is uniformly distributed in one particle. In literatures and the like, many attempts have been made to dissolve Mn in a part of Ni or Co (LiNi 1-x Mn x O 2 etc.) by solid phase method, but the “coprecipitation method” is selected. It is easier to obtain a homogeneous phase at the atomic level. Therefore, the “coprecipitation method” is employed in the examples described later.

共沈前駆体を作製するにあたって、Ｃｏ，Ｎｉ，ＭｎのうちＭｎは酸化されやすく、Ｃｏ，Ｎｉ，Ｍｎが２価の状態で均一に分布した共沈前駆体を作製することが容易ではないため、Ｃｏ，Ｎｉ，Ｍｎの原子レベルでの均一な混合は不十分なものとなりやすい。特に本発明のリチウム過剰型リチウム遷移金属複合酸化物Ａの組成範囲においては、Ｍｎ比率がＣｏ，Ｎｉ比率に比べて高いので、水溶液中の溶存酸素を除去することが特に重要である。溶存酸素を除去する方法としては、酸素を含まないガスをバブリングする方法が挙げられる。酸素を含まないガスとしては、限定されるものではないが、窒素ガス、アルゴンガス、二酸化炭素（ＣＯ２）等を用いることができる。なかでも、後述する実施例のように、共沈炭酸塩前駆体を作製する場合には、酸素を含まないガスとして二酸化炭素を採用すると、炭酸塩がより生成しやすい環境が与えられるため、好ましい。 When preparing a coprecipitation precursor, Mn is easily oxidized among Co, Ni and Mn, and it is not easy to prepare a coprecipitation precursor in which Co, Ni and Mn are uniformly distributed in a divalent state. Uniform mixing at the atomic level of Co, Ni and Mn tends to be insufficient. In particular, in the composition range of the lithium-excess type lithium transition metal composite oxide A of the present invention, since the Mn ratio is higher than the Co and Ni ratios, it is particularly important to remove dissolved oxygen in the aqueous solution. Examples of the method for removing dissolved oxygen include a method of bubbling a gas not containing oxygen. The gas not containing oxygen is not limited, but nitrogen gas, argon gas, carbon dioxide (CO 2 ), or the like can be used. Among these, when preparing a coprecipitated carbonate precursor as in the examples described later, it is preferable to employ carbon dioxide as a gas not containing oxygen because an environment in which carbonate is more easily generated is provided. .

溶液中でＣｏ、Ｎｉ及びＭｎを含有する化合物を共沈させて前駆体を製造する工程におけるｐＨは限定されるものではないが、前記共沈前駆体を共沈炭酸塩前駆体として作製しようとする場合には、７．５〜１１とすることができる。タップ密度を大きくするためには、ｐＨを制御することが好ましい。ｐＨを９．４以下とすることにより、タップ密度を１．２５ｇ／ｃｃ以上とすることができ、高率放電性能を向上させることができる。さらに、ｐＨを８．０以下とすることにより、粒子成長速度を促進できるので、原料水溶液滴下終了後の撹拌継続時間を短縮できる。   Although the pH in the step of producing a precursor by co-precipitation of a compound containing Co, Ni and Mn in a solution is not limited, an attempt is made to prepare the co-precipitation precursor as a co-precipitation carbonate precursor. When it does, it can be set to 7.5-11. In order to increase the tap density, it is preferable to control the pH. By setting the pH to 9.4 or less, the tap density can be set to 1.25 g / cc or more, and the high rate discharge performance can be improved. Furthermore, since the particle growth rate can be accelerated by setting the pH to 8.0 or less, the stirring continuation time after completion of dropping of the raw material aqueous solution can be shortened.

前記共沈前駆体は、ＭｎとＮｉとＣｏとが均一に混合された化合物であることが好ましい。本発明においては、放電容量が大きいリチウム二次電池用活物質を得るために、共沈前駆体を炭酸塩とすることが好ましい。本発明においては、共沈炭酸塩前駆体を用い、後述するように、焼成温度を調整することにより、リチウム過剰型遷移金属複合酸化物Ａのピーク微分細孔容積を０．８５ｍｍ３／（ｇ・ｎｍ）以上とすることができる、また、錯化剤を用いた晶析反応等を用いることによって、より嵩密度の大きな前駆体を作製することもできる。その際、Ｌｉ源と混合・焼成することでより高密度の活物質を得ることができるので電極面積あたりのエネルギー密度を向上させることができる。 The coprecipitation precursor is preferably a compound in which Mn, Ni, and Co are uniformly mixed. In the present invention, in order to obtain an active material for a lithium secondary battery having a large discharge capacity, the coprecipitation precursor is preferably a carbonate. In the present invention, using a coprecipitated carbonate precursor and adjusting the calcination temperature as described later, the peak differential pore volume of the lithium-excess transition metal composite oxide A is 0.85 mm 3 / (g Nm) or more, and by using a crystallization reaction or the like using a complexing agent, a precursor having a larger bulk density can be produced. At that time, a higher density active material can be obtained by mixing and firing with a Li source, so that the energy density per electrode area can be improved.

前記共沈前駆体の原料は、Ｍｎ化合物としては酸化マンガン、炭酸マンガン、硫酸マンガン、硝酸マンガン、酢酸マンガン等を、Ｎｉ化合物としては、水酸化ニッケル、炭酸ニッケル、硫酸ニッケル、硝酸ニッケル、酢酸ニッケル等を、Ｃｏ化合物としては、硫酸コバルト、硝酸コバルト、酢酸コバルト等を一例として挙げることができる。   The raw material of the coprecipitation precursor is manganese oxide, manganese carbonate, manganese sulfate, manganese nitrate, manganese acetate, etc. as the Mn compound, and nickel hydroxide, nickel carbonate, nickel sulfate, nickel nitrate, nickel acetate as the Ni compound. As examples of the Co compound, cobalt sulfate, cobalt nitrate, cobalt acetate, and the like can be given as examples.

本発明においては、アルカリ性を保った反応槽に前記共沈前駆体の原料水溶液を滴下供給して共沈炭酸塩前駆体を得る反応晶析法を採用する。ここで、中和剤として、リチウム化合物、ナトリウム化合物、カリウム化合物等を使用することができるが、炭酸ナトリウム、炭酸ナトリウムと炭酸リチウム、又は、炭酸ナトリウムと炭酸カリウムの混合物を使用することが好ましい。Ｎａを１０００ｐｐｍ以上残存させるために、炭酸ナトリウムと炭酸リチウムのモル比であるＮａ／Ｌｉ、又は、炭酸ナトリウムと炭酸カリウムのモル比であるＮａ／Ｋは、１／１［Ｍ］以上とすることが好ましい。Ｎａ／Ｌｉ又はＮａ／Ｋを１／１［Ｍ］以上とすることにより、引き続く洗浄工程でＮａが除去されすぎて１０００ｐｐｍ未満となってしまう虞を低減できる。   In the present invention, a reaction crystallization method is employed in which a raw material aqueous solution of the coprecipitation precursor is supplied dropwise to a reaction tank maintaining alkalinity to obtain a coprecipitation carbonate precursor. Here, lithium compounds, sodium compounds, potassium compounds, and the like can be used as the neutralizing agent, but it is preferable to use sodium carbonate, sodium carbonate and lithium carbonate, or a mixture of sodium carbonate and potassium carbonate. In order to leave Na at least 1000 ppm, Na / Li, which is the molar ratio of sodium carbonate to lithium carbonate, or Na / K, which is the molar ratio of sodium carbonate to potassium carbonate, is 1/1 [M] or more. Is preferred. By setting Na / Li or Na / K to 1/1 [M] or more, it is possible to reduce the possibility that Na will be excessively removed in the subsequent washing step and become less than 1000 ppm.

前記原料水溶液の滴下速度は、生成する共沈前駆体の１粒子内における元素分布の均一性に大きく影響を与える。特にＭｎは、ＣｏやＮｉと均一な元素分布を形成しにくいので注意が必要である。好ましい滴下速度については、反応槽の大きさ、攪拌条件、ｐＨ、反応温度等にも影響されるが、３０ｍｌ／ｍｉｎ以下が好ましい。放電容量を向上させるためには、滴下速度は１０ｍｌ／ｍｉｎ以下がより好ましく、５ｍｌ／ｍｉｎ以下が最も好ましい。   The dropping speed of the raw material aqueous solution greatly affects the uniformity of element distribution in one particle of the coprecipitation precursor to be generated. In particular, Mn is difficult to form a uniform element distribution with Co and Ni, so care must be taken. The preferred dropping rate is influenced by the reaction vessel size, stirring conditions, pH, reaction temperature, etc., but is preferably 30 ml / min or less. In order to improve the discharge capacity, the dropping rate is more preferably 10 ml / min or less, and most preferably 5 ml / min or less.

また、反応槽内に錯化剤が存在し、かつ一定の対流条件を適用した場合、前記原料水溶液の滴下終了後、さらに攪拌を続けることにより、粒子の自転および攪拌槽内における公転が促進され、この過程で、粒子同士が衝突しつつ、粒子が段階的に同心円球状に成長する。即ち、共沈前駆体は、反応槽内に原料水溶液が滴下された際の金属錯体形成反応、及び、前記金属錯体が反応槽内の滞留中に生じる沈殿形成反応という２段階での反応を経て形成される。従って、前記原料水溶液の滴下終了後、さらに攪拌を続ける時間を適切に選択することにより、目的とする粒子径を備えた共沈前駆体を得ることができる。   In addition, when a complexing agent is present in the reaction tank and a certain convection condition is applied, the particle rotation and revolution in the stirring tank are promoted by continuing the stirring after the dropwise addition of the raw material aqueous solution. In this process, the particles grow concentrically in stages while colliding with each other. That is, the coprecipitation precursor undergoes a reaction in two stages: a metal complex formation reaction when the raw material aqueous solution is dropped into the reaction tank, and a precipitation formation reaction that occurs while the metal complex is retained in the reaction tank. It is formed. Therefore, a coprecipitation precursor having a target particle size can be obtained by appropriately selecting a time for continuing stirring after the dropping of the raw material aqueous solution.

原料水溶液滴下終了後の好ましい攪拌継続時間については、反応槽の大きさ、攪拌条件、ｐＨ、反応温度等にも影響されるが、粒子を均一な球状粒子として成長させるために０．５ｈ以上が好ましく、１ｈ以上がより好ましい。また、粒子径が大きくなりすぎることで電池の低ＳＯＣ領域における出力性能が充分でないものとなる虞を低減させるため、２６ｈ以下が好ましく、２２ｈ以下がより好ましく、１８ｈ以下が最も好ましい。   The preferable stirring duration after completion of dropping of the raw material aqueous solution is influenced by the size of the reaction vessel, stirring conditions, pH, reaction temperature, etc., but 0.5 h or more is required to grow the particles as uniform spherical particles. Preferably, 1 h or more is more preferable. Moreover, in order to reduce the possibility that the output performance in the low SOC region of the battery will be insufficient due to the particle size becoming too large, it is preferably 26h or less, more preferably 22h or less, and most preferably 18h or less.

また、炭酸塩前駆体及びリチウム遷移金属複合酸化物の２次粒子の粒度分布における累積体積が５０％となる粒子径であるＤ５０を４〜１２μｍとするための好ましい攪拌継続時間は、制御するｐＨによって異なる。例えば、ｐＨを７．５〜８．２に制御した場合には、撹拌継続時間は０．５〜１２ｈが好ましく、ｐＨを８．３〜９．４に制御した場合には、撹拌継続時間は１〜１６ｈが好ましい。 Also preferred stirring time duration for accumulation volume and 4~12μm the D 50 is the particle diameter at 50% in the particle size distribution of secondary particles of the carbonate precursor and the lithium transition metal composite oxide is controlled Varies depending on pH. For example, when the pH is controlled to 7.5 to 8.2, the stirring duration is preferably 0.5 to 12 h, and when the pH is controlled to 8.3 to 9.4, the stirring duration is 1-16h is preferable.

炭酸塩前駆体の粒子を、中和剤として炭酸ナトリウム等のナトリウム化合物を使用して作製した場合、その後の洗浄工程において粒子に付着しているナトリウムイオンを洗浄除去するが、本発明においては、Ｎａが１０００ｐｐｍ以上残存するような条件で洗浄除去することが好ましい。例えば、作製した炭酸塩前駆体を吸引ろ過して取り出す際に、イオン交換水２００ｍｌによる洗浄回数を５回とするような条件を採用することができる。   When the carbonate precursor particles are prepared using a sodium compound such as sodium carbonate as a neutralizing agent, sodium ions adhering to the particles are washed away in the subsequent washing step. It is preferable to wash and remove under conditions such that Na remains at 1000 ppm or more. For example, when the produced carbonate precursor is removed by suction filtration, a condition that the number of washings with 200 ml of ion-exchanged water is 5 times can be employed.

炭酸塩前駆体は、８０℃〜１００℃未満で、空気雰囲気中、常圧下で乾燥させることが好ましい。１００℃以上にて乾燥を行うことで短時間でより多くの水分を除去できるが、８０℃にて長時間かけて乾燥させることで、より優れた電極特性を示す活物質とすることができる。その理由は必ずしも明らかではないが、炭酸塩前駆体は比表面積が５０〜１００ｍ２／ｇの多孔体であるため、水分を吸着しやすい構造となっている。そこで、低い温度で乾燥させることによって、前駆体の状態において細孔にある程度の吸着水が残っている状態とした方が、Ｌｉ塩と混合して焼成する焼成工程において、細孔から除去される吸着水と入れ替わるように、その細孔に溶融したＬｉが入り込むことができ、これによって、１００℃で乾燥を行った場合と比べて、より均一な組成の活物質が得られるためではないかと発明者は推察している。なお、１００℃にて乾燥を行って得られた炭酸塩前駆体は黒茶色を呈するが、８０℃にて乾燥を行って得られた炭酸塩前駆体は肌色を呈するので、前駆体の色によって区別ができる。 The carbonate precursor is preferably dried at 80 ° C. to less than 100 ° C. in an air atmosphere under normal pressure. By drying at 100 ° C. or higher, more water can be removed in a short time, but by drying at 80 ° C. for a long time, an active material having more excellent electrode characteristics can be obtained. Although the reason is not necessarily clear, since the carbonate precursor is a porous body having a specific surface area of 50 to 100 m 2 / g, it has a structure that easily adsorbs moisture. Therefore, by drying at a low temperature, a state in which a certain amount of adsorbed water remains in the pores in the state of the precursor is removed from the pores in the firing step of mixing with the Li salt and firing. The invention may be because molten Li can enter the pores so as to replace the adsorbed water, and thereby, an active material having a more uniform composition can be obtained compared with the case of drying at 100 ° C. Have guessed. In addition, although the carbonate precursor obtained by drying at 100 ° C. exhibits a black brown color, the carbonate precursor obtained by drying at 80 ° C. exhibits a skin color, so depending on the color of the precursor Can be distinguished.

そこで、上記知見された前駆体の差異を定量的に評価するため、それぞれの前駆体の色相を測定し、ＪＩＳ Ｚ ８７２１に準拠した日本塗料工業会が発行する塗料用標準色（ＪＰＭＡ Ｓｔａｎｄａｒｄ Ｐａｉｎｔ Ｃｏｌｏｒｓ）２０１１年度Ｆ版と比較した。色相の測定には、コニカミノルタ社製カラーリーダーＣＲ１０を用いた。この測定方法によれば、明度を表すｄＬ＊の値は、白い方が大きくなり、黒い方が小さくなる。また、色相を表すｄａ＊の値は、赤色が強い方が大きくなり、緑色が強い方（赤色が弱い方）が小さくなる。また、色相を表すｄｂ＊の値は、黄色が強い方が大きくなり、青色が強い方（黄色が弱い方）が大きくなる。
１００℃乾燥品の色相は、標準色Ｆ０５−２０Ｂと比べて、赤色方向に標準色Ｆ０５−４０Ｄに至る範囲内にあり、また、標準色ＦＮ−１０と比べて、白色方向に標準色ＦＮ−２５に至る範囲内にあることがわかった。中でも、標準色Ｆ０５−２０Ｂが呈する色相との色差が最も小さいものと認められた。
一方、８０℃乾燥品の色相は、標準色Ｆ１９−５０Ｆと比べて、白色方向に標準色Ｆ１９−７０Ｆに至る範囲内にあり、また、標準色Ｆ０９−８０Ｄと比べて、黒色方向に標準色Ｆ０９−６０Ｈに至る範囲内にあることがわかった。中でも、標準色Ｆ１９−５０Ｆが呈する色相との色差が最も小さいものと認められた。
以上の知見から、炭酸塩前駆体の色相は、標準色Ｆ０５−２０Ｂに比べて、ｄＬ，ｄａ及びｄｂの全てにおいて＋方向であるものが好ましく、ｄＬが＋５以上、ｄａが＋２以上、ｄｂが＋５以上であることがより好ましいといえる。 Therefore, in order to quantitatively evaluate the difference in the precursors found above, the hues of the respective precursors are measured, and standard colors for paints (JPMA Standard Paint Colors) issued by the Japan Paint Manufacturers Association in accordance with JIS Z 8721. ) Compared with the 2011 F version. For measuring the hue, a color reader CR10 manufactured by Konica Minolta Co., Ltd. was used. According to this measuring method, the value of dL * representing lightness is larger in white and smaller in black. Further, the value of da * representing the hue is larger when red is stronger and smaller when green is stronger (red is weaker). In addition, the value of db * representing the hue becomes larger when yellow is stronger and larger when blue is stronger (yellow is weaker).
The hue of the dried product at 100 ° C. is in the range reaching the standard color F05-40D in the red direction as compared with the standard color F05-20B, and the standard color FN− in the white direction as compared with the standard color FN-10. It was found to be in the range up to 25. Among these, it was recognized that the color difference from the hue exhibited by the standard color F05-20B was the smallest.
On the other hand, the hue of the dried product at 80 ° C. is within the range reaching the standard color F19-70F in the white direction compared to the standard color F19-50F, and the standard color in the black direction compared to the standard color F09-80D. It was found to be in the range up to F09-60H. Especially, it was recognized that the color difference with the hue which standard color F19-50F exhibits is the smallest.
From the above knowledge, the hue of the carbonate precursor is preferably positive in all of dL, da and db as compared with the standard color F05-20B, dL is +5 or more, da is +2 or more, and db is It can be said that +5 or more is more preferable.

本発明のリチウム過剰型リチウム遷移金属化合物Ａは、前記炭酸塩前駆体とＬｉ化合物とを混合した後、熱処理することで好適に作製することができる。Ｌｉ化合物としては、水酸化リチウム、炭酸リチウム、硝酸リチウム、酢酸リチウム等を用いることで好適に製造することができる。但し、Ｌｉ化合物の量については、焼成中にＬｉ化合物の一部が消失することを見込んで、１〜５％程度過剰に仕込むことが好ましい。   The lithium-excess type lithium transition metal compound A of the present invention can be suitably prepared by mixing the carbonate precursor and the Li compound and then performing a heat treatment. As a Li compound, it can manufacture suitably by using lithium hydroxide, lithium carbonate, lithium nitrate, lithium acetate, etc. However, with respect to the amount of the Li compound, it is preferable to add an excess of about 1 to 5% in view of the disappearance of a part of the Li compound during firing.

本発明においては、リチウム遷移金属複合酸化物Ａ中のＮａの含有量を１０００ｐｐｍ以上とするために、炭酸塩前駆体に含まれるＮａが１０００ｐｐｍ以下であっても、焼成工程においてＬｉ化合物と共にＮａ化合物を、前記炭酸塩前駆体と混合することで活物質中に含まれるＮａ量を１０００ｐｐｍ以上とすることができる。Ｎａ化合物としては炭酸ナトリウムが好ましい。   In the present invention, in order to make the content of Na in the lithium transition metal composite oxide A 1000 ppm or more, even if the Na contained in the carbonate precursor is 1000 ppm or less, the Na compound is combined with the Li compound in the firing step. Is mixed with the carbonate precursor to make the amount of Na contained in the active material 1000 ppm or more. As the Na compound, sodium carbonate is preferable.

焼成温度は、活物質の可逆容量に影響を与える。
焼成温度が高すぎると、得られた活物質が酸素放出反応を伴って崩壊すると共に、主相の六方晶に加えて単斜晶のＬｉ［Ｌｉ１／３Ｍｎ２／３］Ｏ２型に規定される相が、固溶相としてではなく、分相して観察される傾向がある。このような分相が多く含まれすぎると、活物質の可逆容量の減少を導くので好ましくない。このような材料では、Ｘ線回折図上３５°付近及び４５°付近に不純物ピークが観察される。従って、焼成温度は、活物質の酸素放出反応の影響する温度未満とすることが好ましい。活物質の酸素放出温度は、本発明に係る組成範囲においては、概ね１０００℃以上であるが、活物質の組成によって酸素放出温度に若干の差があるので、あらかじめ活物質の酸素放出温度を確認しておくことが好ましい。特に試料に含まれるＣｏ量が多いほど前駆体の酸素放出温度は低温側にシフトすることが確認されているので注意が必要である。活物質の酸素放出温度を確認する方法としては、焼成反応過程をシミュレートするために、共沈前駆体とリチウム化合物を混合したものを熱重量分析（ＤＴＡ−ＴＧ測定）に供してもよいが、この方法では測定機器の試料室に用いている白金が揮発したＬｉ成分により腐食されて機器を痛めるおそれがあるので、あらかじめ５００℃程度の焼成温度を採用してある程度結晶化を進行させた組成物を熱重量分析に供するのが良い。 The firing temperature affects the reversible capacity of the active material.
When the firing temperature is too high, the obtained active material collapses with an oxygen releasing reaction, and in addition to the hexagonal crystal of the main phase, the monoclinic Li [Li 1/3 Mn 2/3 ] O 2 type is obtained. The defined phase tends to be observed as a phase separation rather than as a solid solution phase. If too many such phase separations are contained, it is not preferable because it leads to a reduction in the reversible capacity of the active material. In such materials, impurity peaks are observed around 35 ° and 45 ° on the X-ray diffraction pattern. Therefore, the firing temperature is preferably less than the temperature at which the oxygen release reaction of the active material affects. The oxygen release temperature of the active material is approximately 1000 ° C. or higher in the composition range according to the present invention. However, there is a slight difference in the oxygen release temperature depending on the composition of the active material. It is preferable to keep it. In particular, it is confirmed that the oxygen release temperature of the precursor shifts to the lower temperature side as the amount of Co contained in the sample increases. As a method for confirming the oxygen release temperature of the active material, a mixture of a coprecipitation precursor and a lithium compound may be subjected to thermogravimetric analysis (DTA-TG measurement) in order to simulate the firing reaction process. In this method, the platinum used in the sample chamber of the measuring instrument may be corroded by the Li component volatilized, and the instrument may be damaged. Therefore, a composition in which crystallization is advanced to some extent by adopting a firing temperature of about 500 ° C. in advance. Goods should be subjected to thermogravimetric analysis.

一方、焼成温度が低すぎると、結晶化が十分に進まず、電極特性が低下する傾向がある。本発明において、共沈水酸化物を前駆体として用いたときには焼成温度は少なくとも７００℃以上とすることが好ましい。また、共沈炭酸塩を前駆体として用いたときには焼成温度は少なくとも８００℃以上とすることが好ましい。特に、前駆体が共沈炭酸塩である場合の最適な焼成温度は、前駆体に含まれるＣｏ量が多いほど、より低い温度となる傾向がある。このように１次粒子を構成する結晶子を十分に結晶化させることにより、結晶粒界の抵抗を軽減し、円滑なリチウムイオン輸送を促すことができる。
本発明者らは、本発明活物質の回折ピークの半値幅を詳細に解析することにより、前駆体が共沈炭酸塩である場合においては、焼成温度が７５０℃未満の温度で合成した試料においては格子内にひずみが残存しており、７５０℃以上の温度で合成することで顕著にひずみを除去することができることを確認した。また、結晶子のサイズは合成温度が上昇するに比例して大きくなるものであった。よって、本発明活物質の組成においても、系内に格子のひずみがほとんどなく、かつ結晶子サイズが十分成長した粒子を志向することで良好な放電容量を得られるものであった。具体的には、格子定数に及ぼすひずみ量が２％以下、かつ結晶子サイズが５０ｎｍ以上に成長しているような合成温度（焼成温度）及びＬｉ／Ｍｅ比組成を採用することが好ましいことがわかった。これらを電極として成型して充放電をおこなうことで膨張収縮による変化も見られるが、充放電過程においても結晶子サイズは３０ｎｍ以上を保っていることが得られる効果として好ましい。 On the other hand, if the firing temperature is too low, crystallization does not proceed sufficiently and the electrode characteristics tend to deteriorate. In the present invention, when coprecipitated hydroxide is used as a precursor, the firing temperature is preferably at least 700 ° C. or higher. When coprecipitated carbonate is used as a precursor, the firing temperature is preferably at least 800 ° C. or higher. In particular, when the precursor is a coprecipitated carbonate, the optimum firing temperature tends to be lower as the amount of Co contained in the precursor is larger. Thus, by sufficiently crystallizing the crystallites constituting the primary particles, the resistance of the crystal grain boundary can be reduced and smooth lithium ion transport can be promoted.
The present inventors analyzed the half width of the diffraction peak of the active material of the present invention in detail, and in the case where the precursor is a coprecipitated carbonate, in the sample synthesized at a temperature of less than 750 ° C. It was confirmed that strain remained in the lattice and could be remarkably removed by synthesis at a temperature of 750 ° C. or higher. The crystallite size was increased in proportion to the increase in the synthesis temperature. Therefore, even in the composition of the active material of the present invention, a favorable discharge capacity can be obtained by aiming at a particle having almost no lattice distortion in the system and having a sufficiently grown crystallite size. Specifically, it is preferable to employ a synthesis temperature (firing temperature) and a Li / Me ratio composition in which the strain amount affecting the lattice constant is 2% or less and the crystallite size is grown to 50 nm or more. all right. Although changes due to expansion and contraction are observed by charging and discharging by molding these as electrodes, it is preferable as an effect that the crystallite size is maintained at 30 nm or more in the charging and discharging process.

上記のように、焼成温度は、活物質の酸素放出温度に関係するが、活物質から酸素が放出される焼成温度に至らずとも、９００℃以上において１次粒子が大きく成長することによる結晶化現象が見られる。これは、焼成後の活物質を走査型電子顕微鏡（ＳＥＭ）で観察することにより確認できる。９００℃を超えた合成温度を経て合成した活物質は１次粒子が０．５μｍ以上に成長しており、充放電反応中における活物質中のＬｉ＋移動に不利な状態となり、高率放電性能が低下する。１次粒子の大きさは０．５μｍ未満であることが好ましく、０．３μｍ以下であることがより好ましい。 As described above, the calcination temperature is related to the oxygen release temperature of the active material, but crystallization is caused by large growth of primary particles at 900 ° C. or higher without reaching the calcination temperature at which oxygen is released from the active material. The phenomenon is seen. This can be confirmed by observing the fired active material with a scanning electron microscope (SEM). The active material synthesized through a synthesis temperature exceeding 900 ° C. has primary particles grown to 0.5 μm or more, and is in a disadvantageous state for Li + movement in the active material during the charge / discharge reaction, and has a high rate discharge performance. Decreases. The size of the primary particles is preferably less than 0.5 μm, and more preferably 0.3 μm or less.

本発明のリチウム過剰型遷移金属複合酸化物Ａにおいて、ピーク微分細孔容積は、焼成温度の影響を受け、焼成温度が高くなると、ピーク微分細孔容積は小さくなるから、ピーク微分細孔容積を０．８５ｍｍ３／（ｇ・ｎｍ）以上とするために、焼成温度は９００℃以下とすることが好ましい。
本発明のリチウム過剰型リチウム遷移金属複合酸化物Ａにおいて、Ｌｉ／Ｍｅのモル比（１＋α）／（１−α）が１．１≦（１＋α）／（１−α）＜１．５である場合、焼成温度は、８００〜９００℃とすることが好ましい。 In the lithium-excess type transition metal composite oxide A of the present invention, the peak differential pore volume is affected by the firing temperature, and the peak differential pore volume decreases as the firing temperature increases. In order to obtain 0.85 mm 3 / (g · nm) or more, the firing temperature is preferably 900 ° C. or less.
In the lithium-excess type lithium transition metal composite oxide A of the present invention, the molar ratio (1 + α) / (1-α) of Li / Me is 1.1 ≦ (1 + α) / (1-α) <1.5. In this case, the firing temperature is preferably 800 to 900 ° C.

ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂについては、上記［００３１］のように、周知のものを用いることができ、反応条件も周知のものである。例えば、アルカリ性を保った反応槽に、上記のリチウム過剰型リチウム遷移金属複合酸化物Ａと同様のＣｏ、Ｎｉ、Ｍｎの塩を含有する共沈前駆体の原料水溶液（但し、Ｍｎの含有量が少ない点で、リチウム過剰型リチウム遷移金属複合酸化物Ａとは相違する）を滴下供給して共沈前駆体を得る反応晶析法を採用する。この際に、中和剤として、水酸化ナトリウム等を使用して、共沈水酸化物前駆体とすることが好ましい。また、反応層のｐＨ１０〜１２において、平均粒子径（Ｄ５０）を４〜２０μｍとするために、原料水溶液滴下終了後の反応槽内の攪拌継続時間を１〜３０時間とすることが好ましい。
本発明のＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂは、前記水酸化物前駆体とＬｉ化合物とを混合した後、熱処理することで作製することができるが、Ｌｉ化合物としては、水酸化リチウムが好ましく、粒子径を大きくするために、熱処理温度は、８００〜１１００℃とすることが好ましい。 As the LiMeO 2 type lithium transition metal composite oxide B, a well-known one can be used as in the above [0031], and the reaction conditions are also well-known. For example, a raw material aqueous solution of a coprecipitation precursor containing a salt of Co, Ni, and Mn similar to the above lithium-excess type lithium transition metal composite oxide A in a reaction tank that maintains alkalinity (provided that the content of Mn is A reaction crystallization method is employed in which a coprecipitation precursor is obtained by supplying dropwise a lithium-excess type lithium transition metal composite oxide A). At this time, it is preferable to use sodium hydroxide or the like as a neutralizing agent to form a coprecipitated hydroxide precursor. Further, in pH10~12 reaction layer, the average particle diameter (D 50) to a 4 to 20 .mu.m, stirring duration in the reactor after the raw material aqueous solution dropwise ends preferably 1 to 30 hours.
The LiMeO 2 type lithium transition metal composite oxide B of the present invention can be prepared by mixing the hydroxide precursor and the Li compound and then heat-treating the lithium compound. Preferably, the heat treatment temperature is preferably 800 to 1100 ° C. in order to increase the particle diameter.

負極材料としては、限定されるものではなく、リチウムイオンを放出あるいは吸蔵することのできる形態のものであればどれを選択してもよい。例えば、Ｌｉ［Ｌｉ１／３Ｔｉ５／３］Ｏ４に代表されるスピネル型結晶構造を有するチタン酸リチウム等のチタン系材料、ＳｉやＳｂ，Ｓｎ系などの合金系材料リチウム金属、リチウム合金（リチウム−シリコン、リチウム−アルミニウム，リチウム−鉛，リチウム−スズ，リチウム−アルミニウム−スズ，リチウム−ガリウム，及びウッド合金等のリチウム金属含有合金）、リチウム複合酸化物（リチウム−チタン）、酸化珪素の他、リチウムを吸蔵・放出可能な合金、炭素材料（例えばグラファイト、ハードカーボン、低温焼成炭素、非晶質カーボン等）等が挙げられる。 The negative electrode material is not limited, and any negative electrode material may be selected as long as it can release or occlude lithium ions. For example, titanium-based materials such as lithium titanate having a spinel crystal structure represented by Li [Li 1/3 Ti 5/3 ] O 4 , alloy-based materials such as Si, Sb, and Sn-based lithium metal, lithium alloys (Lithium metal-containing alloys such as lithium-silicon, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood alloys), lithium composite oxide (lithium-titanium), silicon oxide In addition, an alloy capable of inserting and extracting lithium, a carbon material (for example, graphite, hard carbon, low-temperature fired carbon, amorphous carbon, etc.) can be used.

正極活物質の粉体は、上記のように所定の粒子径とするが、負極材料の粉体は、平均粒子径１００μｍ以下であることが望ましい。粉体を所定の形状で得るためには粉砕機や分級機が用いられる。例えば乳鉢、ボールミル、サンドミル、振動ボールミル、遊星ボールミル、ジェットミル、カウンタージェトミル、旋回気流型ジェットミルや篩等が用いられる。粉砕時には水、あるいはヘキサン等の有機溶剤を共存させた湿式粉砕を用いることもできる。分級方法としては、特に限定はなく、篩や風力分級機などが、乾式、湿式ともに必要に応じて用いられる。   The positive electrode active material powder has a predetermined particle size as described above, but the negative electrode material powder desirably has an average particle size of 100 μm or less. In order to obtain the powder in a predetermined shape, a pulverizer or a classifier is used. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a planetary ball mill, a jet mill, a counter jet mill, a swirling air flow type jet mill or a sieve is used. At the time of pulverization, wet pulverization in the presence of water or an organic solvent such as hexane may be used. There is no particular limitation on the classification method, and a sieve, an air classifier, or the like is used as needed for both dry and wet methods.

以上、正極及び負極の主要構成成分である正極活物質及び負極材料について詳述したが、前記正極及び負極には、前記主要構成成分の他に、導電剤、結着剤、増粘剤、フィラー等が、他の構成成分として含有されてもよい。   The positive electrode active material and the negative electrode material, which are the main components of the positive electrode and the negative electrode, have been described in detail above. In addition to the main components, the positive electrode and the negative electrode include a conductive agent, a binder, a thickener, and a filler. Etc. may be contained as other constituents.

導電剤としては、電池性能に悪影響を及ぼさない電子伝導性材料であれば限定されないが、通常、天然黒鉛（鱗状黒鉛，鱗片状黒鉛，土状黒鉛等）、人造黒鉛、カーボンブラック、アセチレンブラック、ケッチェンブラック、カーボンウイスカー、炭素繊維、金属（銅，ニッケル，アルミニウム，銀，金等）粉、金属繊維、導電性セラミックス材料等の導電性材料を１種またはそれらの混合物として含ませることができる。   The conductive agent is not limited as long as it is an electron conductive material that does not adversely affect the battery performance. Usually, natural graphite (such as scaly graphite, scaly graphite, earthy graphite), artificial graphite, carbon black, acetylene black, Conductive materials such as ketjen black, carbon whisker, carbon fiber, metal (copper, nickel, aluminum, silver, gold, etc.) powder, metal fiber, and conductive ceramic material can be included as one kind or a mixture thereof. .

これらの中で、導電剤としては、電子伝導性及び塗工性の観点よりアセチレンブラックが望ましい。導電剤の添加量は、正極または負極の総重量に対して０．１重量％〜５０重量％が好ましく、特に０．５重量％〜３０重量％が好ましい。特にアセチレンブラックを０．１〜０．５μｍの超微粒子に粉砕して用いると必要炭素量を削減できるため望ましい。これらの混合方法は、物理的な混合であり、その理想とするところは均一混合である。そのため、Ｖ型混合機、Ｓ型混合機、擂かい機、ボールミル、遊星ボールミルといったような粉体混合機を乾式、あるいは湿式で混合することが可能である。   Among these, as the conductive agent, acetylene black is desirable from the viewpoints of electron conductivity and coatability. The addition amount of the conductive agent is preferably 0.1% by weight to 50% by weight, and particularly preferably 0.5% by weight to 30% by weight with respect to the total weight of the positive electrode or the negative electrode. In particular, it is desirable to use acetylene black by pulverizing into ultrafine particles of 0.1 to 0.5 μm because the required carbon amount can be reduced. These mixing methods are physical mixing, and the ideal is uniform mixing. Therefore, powder mixers such as V-type mixers, S-type mixers, crackers, ball mills, and planetary ball mills can be mixed dry or wet.

前記結着剤としては、通常、ポリテトラフルオロエチレン（ＰＴＦＥ），ポリフッ化ビニリデン（ＰＶＤＦ），ポリエチレン，ポリプロピレン等の熱可塑性樹脂、エチレン−プロピレン−ジエンターポリマー（ＥＰＤＭ），スルホン化ＥＰＤＭ，スチレンブタジエンゴム（ＳＢＲ）、フッ素ゴム等のゴム弾性を有するポリマーを１種または２種以上の混合物として用いることができる。結着剤の添加量は、正極または負極の総重量に対して１〜５０重量％が好ましく、特に２〜３０重量％が好ましい。   The binder is usually a thermoplastic resin such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene. Polymers having rubber elasticity such as rubber (SBR) and fluororubber can be used as one kind or a mixture of two or more kinds. The addition amount of the binder is preferably 1 to 50% by weight, particularly preferably 2 to 30% by weight, based on the total weight of the positive electrode or the negative electrode.

フィラーとしては、電池性能に悪影響を及ぼさない材料であれば何でも良い。通常、ポリプロピレン，ポリエチレン等のオレフィン系ポリマー、無定形シリカ、アルミナ、ゼオライト、ガラス、炭素等が用いられる。フィラーの添加量は、正極または負極の総重量に対して添加量は３０重量％以下が好ましい。   As the filler, any material that does not adversely affect the battery performance may be used. Usually, olefin polymers such as polypropylene and polyethylene, amorphous silica, alumina, zeolite, glass, carbon and the like are used. The addition amount of the filler is preferably 30% by weight or less with respect to the total weight of the positive electrode or the negative electrode.

正極及び負極は、前記主要構成成分（正極においては正極活物質、負極においては負極材料）、およびその他の材料を混練し合剤とし、Ｎ−メチルピロリドン，トルエン等の有機溶媒又は水に混合させた後、得られた混合液をアルミニウム箔等の集電体の上に塗布し、または圧着して５０℃〜２５０℃程度の温度で、２時間程度加熱処理することにより好適に作製される。前記塗布方法については、例えば、アプリケーターロールなどのローラーコーティング、スクリーンコーティング、ドクターブレード方式、スピンコーティング、バーコータ等の手段を用いて任意の厚さ及び任意の形状に塗布することが望ましいが、これらに限定されるものではない。   The positive electrode and the negative electrode are prepared by mixing the main constituents (positive electrode active material in the positive electrode, negative electrode material in the negative electrode) and other materials into a mixture and mixing with an organic solvent such as N-methylpyrrolidone or toluene or water. After that, the obtained mixed solution is applied on a current collector such as an aluminum foil, or is pressure-bonded and heat-treated at a temperature of about 50 ° C. to 250 ° C. for about 2 hours. About the application method, for example, it is desirable to apply to any thickness and any shape using means such as roller coating such as applicator roll, screen coating, doctor blade method, spin coating, bar coater, etc. It is not limited.

本発明に係るリチウム二次電池に用いる非水電解質は、限定されるものではなく、一般にリチウム電池等への使用が提案されているものが使用可能である。非水電解質に用いる非水溶媒としては、プロピレンカーボネート、エチレンカーボネート、ブチレンカーボネート、クロロエチレンカーボネート、ビニレンカーボネート等の環状炭酸エステル類；γ−ブチロラクトン、γ−バレロラクトン等の環状エステル類；ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネート等の鎖状カーボネート類；ギ酸メチル、酢酸メチル、酪酸メチル等の鎖状エステル類；テトラヒドロフランまたはその誘導体；１，３−ジオキサン、１，４−ジオキサン、１，２−ジメトキシエタン、１，４−ジブトキシエタン、メチルジグライム等のエーテル類；アセトニトリル、ベンゾニトリル等のニトリル類；ジオキソランまたはその誘導体；エチレンスルフィド、スルホラン、スルトンまたはその誘導体等の単独またはそれら２種以上の混合物等を挙げることができるが、これらに限定されるものではない。   The nonaqueous electrolyte used for the lithium secondary battery according to the present invention is not limited, and those generally proposed for use in lithium batteries and the like can be used. Examples of the nonaqueous solvent used for the nonaqueous electrolyte include cyclic carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, chloroethylene carbonate, and vinylene carbonate; cyclic esters such as γ-butyrolactone and γ-valerolactone; dimethyl carbonate, Chain carbonates such as diethyl carbonate and ethyl methyl carbonate; chain esters such as methyl formate, methyl acetate and methyl butyrate; tetrahydrofuran or derivatives thereof; 1,3-dioxane, 1,4-dioxane, 1,2-dimethoxy Ethers such as ethane, 1,4-dibutoxyethane and methyldiglyme; Nitriles such as acetonitrile and benzonitrile; Dioxolane or derivatives thereof; Ethylene sulfide, sulfolane, sultone or derivatives thereof Examples thereof include a conductor alone or a mixture of two or more thereof, but are not limited thereto.

非水電解質に用いる電解質塩としては、例えば、ＬｉＣｌＯ4，ＬｉＢＦ4，ＬｉＡｓＦ6，ＬｉＰＦ6，ＬｉＳＣＮ，ＬｉＢｒ，ＬｉＩ，Ｌｉ2ＳＯ4，Ｌｉ2Ｂ10Ｃｌ10，ＮａＣｌＯ4，ＮａＩ，ＮａＳＣＮ，ＮａＢｒ，ＫＣｌＯ4，ＫＳＣＮ等のリチウム（Ｌｉ）、ナトリウム（Ｎａ）またはカリウム（Ｋ）の１種を含む無機イオン塩、ＬｉＣＦ3ＳＯ3，ＬｉＮ（ＣＦ3ＳＯ2）2，ＬｉＮ（Ｃ2Ｆ5ＳＯ2）2，ＬｉＮ（ＣＦ3ＳＯ2）（Ｃ4Ｆ9ＳＯ2），ＬｉＣ（ＣＦ3ＳＯ2）3，ＬｉＣ（Ｃ2Ｆ5ＳＯ2）3，（ＣＨ3）4ＮＢＦ4，（ＣＨ3）4ＮＢｒ，（Ｃ2Ｈ5）4ＮＣｌＯ4，（Ｃ2Ｈ5）4ＮＩ，（Ｃ3Ｈ7）4ＮＢｒ，（ｎ−Ｃ4Ｈ9）4ＮＣｌＯ4，（ｎ−Ｃ4Ｈ9）4ＮＩ，（Ｃ2Ｈ5）4Ｎ−ｍａｌｅａｔｅ，（Ｃ2Ｈ5）4Ｎ−ｂｅｎｚｏａｔｅ，（Ｃ2Ｈ5）4Ｎ−ｐｈｔｈａｌａｔｅ、ステアリルスルホン酸リチウム、オクチルスルホン酸リチウム、ドデシルベンゼンスルホン酸リチウム等の有機イオン塩等が挙げられ、これらのイオン性化合物を単独、あるいは２種類以上混合して用いることが可能である。 Examples of the electrolyte salt used for the nonaqueous electrolyte include LiClO 4 , LiBF 4 , LiAsF 6 , LiPF 6 , LiSCN, LiBr, LiI, Li 2 SO 4 , Li 2 B 10 Cl 10 , NaClO 4 , NaI, NaSCN, NaBr. , KClO 4 , KSCN, and other inorganic ion salts containing one of lithium (Li), sodium (Na), or potassium (K), LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiN (C 2 F 5 SO 2 ) 2 , LiN (CF 3 SO 2 ) (C 4 F 9 SO 2 ), LiC (CF 3 SO 2 ) 3 , LiC (C 2 F 5 SO 2 ) 3 , (CH 3 ) 4 NBF 4 , ( CH 3 ) 4 NBr, (C 2 H 5 ) 4 NClO 4 , (C 2 H 5 ) 4 NI, (C 3 H 7 ) 4 NBr, (n-C 4 H 9 ) 4 NClO 4 , (n-C 4 H 9) 4 NI, ( C 2 H 5) 4 N-mal ate, (C 2 H 5) 4 N-benzoate, (C 2 H 5) 4 N-phthalate, lithium stearyl sulfonate, lithium octyl sulfonate, organic ion salts of lithium dodecyl benzene sulfonate, and the like. These These ionic compounds can be used alone or in admixture of two or more.

さらに、ＬｉＰＦ6又はＬｉＢＦ4と、ＬｉＮ（Ｃ2Ｆ5ＳＯ2）2のようなパーフルオロアルキル基を有するリチウム塩とを混合して用いることにより、さらに電解質の粘度を下げることができるので、低温特性をさらに高めることができ、また、自己放電を抑制することができ、より望ましい。 Furthermore, by mixing and using LiPF 6 or LiBF 4 and a lithium salt having a perfluoroalkyl group such as LiN (C 2 F 5 SO 2 ) 2 , the viscosity of the electrolyte can be further reduced. The low temperature characteristics can be further improved, and self-discharge can be suppressed, which is more desirable.

また、非水電解質として常温溶融塩やイオン液体を用いてもよい。   Moreover, you may use normal temperature molten salt and an ionic liquid as a nonaqueous electrolyte.

非水電解質における電解質塩の濃度としては、高い電池特性を有する非水電解質電池を確実に得るために、０．１ｍｏｌ／ｌ〜５ｍｏｌ／ｌが好ましく、さらに好ましくは、０．５ｍｏｌ／ｌ〜２．５ｍｏｌ／ｌである。   The concentration of the electrolyte salt in the non-aqueous electrolyte is preferably 0.1 mol / l to 5 mol / l, more preferably 0.5 mol / l to 2 in order to reliably obtain a non-aqueous electrolyte battery having high battery characteristics. .5 mol / l.

セパレータとしては、優れた高率放電性能を示す多孔膜や不織布等を、単独あるいは併用することが好ましい。非水電解質電池用セパレータを構成する材料としては、例えばポリエチレン，ポリプロピレン等に代表されるポリオレフィン系樹脂、ポリエチレンテレフタレート，ポリブチレンテレフタレート等に代表されるポリエステル系樹脂、ポリフッ化ビニリデン、フッ化ビニリデン−ヘキサフルオロプロピレン共重合体、フッ化ビニリデン−パーフルオロビニルエーテル共重合体、フッ化ビニリデン−テトラフルオロエチレン共重合体、フッ化ビニリデン−トリフルオロエチレン共重合体、フッ化ビニリデン−フルオロエチレン共重合体、フッ化ビニリデン−ヘキサフルオロアセトン共重合体、フッ化ビニリデン−エチレン共重合体、フッ化ビニリデン−プロピレン共重合体、フッ化ビニリデン−トリフルオロプロピレン共重合体、フッ化ビニリデン−テトラフルオロエチレン−ヘキサフルオロプロピレン共重合体、フッ化ビニリデン−エチレン−テトラフルオロエチレン共重合体等を挙げることができる。   As the separator, it is preferable to use a porous film or a non-woven fabric exhibiting excellent high rate discharge performance alone or in combination. Examples of the material constituting the separator for a nonaqueous electrolyte battery include polyolefin resins typified by polyethylene and polypropylene, polyester resins typified by polyethylene terephthalate and polybutylene terephthalate, polyvinylidene fluoride, and vinylidene fluoride-hexa. Fluoropropylene copolymer, vinylidene fluoride-perfluorovinyl ether copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-fluoroethylene copolymer, fluorine Vinylidene fluoride-hexafluoroacetone copolymer, vinylidene fluoride-ethylene copolymer, vinylidene fluoride-propylene copolymer, vinylidene fluoride-trifluoropropylene copolymer, vinylidene fluoride - tetrafluoroethylene - hexafluoropropylene copolymer, vinylidene fluoride - ethylene - can be mentioned tetrafluoroethylene copolymer.

セパレータの空孔率は強度の観点から９８体積％以下が好ましい。また、充放電特性の観点から空孔率は２０体積％以上が好ましい。   The porosity of the separator is preferably 98% by volume or less from the viewpoint of strength. Further, the porosity is preferably 20% by volume or more from the viewpoint of charge / discharge characteristics.

また、セパレータは、例えばアクリロニトリル、エチレンオキシド、プロピレンオキシド、メチルメタアクリレート、ビニルアセテート、ビニルピロリドン、ポリフッ化ビニリデン等のポリマーと電解質とで構成されるポリマーゲルを用いてもよい。非水電解質を上記のようにゲル状態で用いると、漏液を防止する効果がある点で好ましい。   The separator may be a polymer gel composed of a polymer such as acrylonitrile, ethylene oxide, propylene oxide, methyl methacrylate, vinyl acetate, vinyl pyrrolidone, polyvinylidene fluoride, and an electrolyte. Use of the non-aqueous electrolyte in the gel state as described above is preferable in that it has an effect of preventing leakage.

さらに、セパレータは、上述したような多孔膜や不織布等とポリマーゲルを併用して用いると、電解質の保液性が向上するため望ましい。即ち、ポリエチレン微孔膜の表面及び微孔壁面に厚さ数μｍ以下の親溶媒性ポリマーを被覆したフィルムを形成し、前記フィルムの微孔内に電解質を保持させることで、前記親溶媒性ポリマーがゲル化する。   Furthermore, it is desirable that the separator be used in combination with the above-described porous film, nonwoven fabric, or the like and a polymer gel because the liquid retention of the electrolyte is improved. That is, by forming a film in which the surface of the polyethylene microporous membrane and the microporous wall are coated with a solvophilic polymer having a thickness of several μm or less, and holding the electrolyte in the micropores of the film, Gels.

前記親溶媒性ポリマーとしては、ポリフッ化ビニリデンの他、エチレンオキシド基やエステル基等を有するアクリレートモノマー、エポキシモノマー、イソシアナート基を有するモノマー等が架橋したポリマー等が挙げられる。該モノマーは、ラジカル開始剤を併用して加熱や紫外線（ＵＶ）を用いたり、電子線（ＥＢ）等の活性光線等を用いて架橋反応を行わせることが可能である。   Examples of the solvophilic polymer include polyvinylidene fluoride, an acrylate monomer having an ethylene oxide group or an ester group, an epoxy monomer, a polymer having a monomer having an isocyanate group, and the like crosslinked. The monomer can be subjected to a crosslinking reaction using a radical initiator in combination with heating or ultraviolet rays (UV), or using an actinic ray such as an electron beam (EB).

その他の電池の構成要素としては、端子、絶縁板、電池ケース等があるが、これらの部品は従来用いられてきたものをそのまま用いて差し支えない。   Other battery components include a terminal, an insulating plate, a battery case, and the like, but these components may be used as they are.

図１に、本発明に係るリチウム二次電池の一実施形態である矩形状のリチウム二次電池１の外観斜視図を示す。なお、同図は、容器内部を透視した図としている。図１に示すリチウム二次電池１は、電極群２が電池容器３に収納されている。電極群２は、正極活物質を備える正極と、負極活物質を備える負極とが、セパレータを介して捲回されることにより形成されている。正極は、正極リード４’を介して正極端子４と電気的に接続され、負極は、負極リード５’を介して負極端子５と電気的に接続されている。   FIG. 1 shows an external perspective view of a rectangular lithium secondary battery 1 which is an embodiment of a lithium secondary battery according to the present invention. In the figure, the inside of the container is seen through. In the lithium secondary battery 1 shown in FIG. 1, an electrode group 2 is housed in a battery container 3. The electrode group 2 is formed by winding a positive electrode including a positive electrode active material and a negative electrode including a negative electrode active material via a separator. The positive electrode is electrically connected to the positive electrode terminal 4 via the positive electrode lead 4 ′, and the negative electrode is electrically connected to the negative electrode terminal 5 via the negative electrode lead 5 ′.

本発明に係るリチウム二次電池の形状については特に限定されるものではなく、円筒型電池、角型電池（矩形状の電池）、扁平型電池等が一例として挙げられる。本発明は、上記のリチウム二次電池を複数個集合した蓄電装置としても実現することができる。蓄電装置の一実施形態を図２に示す。図２において、蓄電装置３０は、複数の蓄電ユニット２０を備えている。それぞれの蓄電ユニット２０は、複数のリチウム二次電池１を備えている。前記蓄電装置３０は、電気自動車（ＥＶ）、ハイブリッド自動車（ＨＥＶ）、プラグインハイブリッド自動車（ＰＨＥＶ）等の自動車用電源として搭載することができる。   The shape of the lithium secondary battery according to the present invention is not particularly limited, and examples thereof include a cylindrical battery, a square battery (rectangular battery), a flat battery, and the like. The present invention can also be realized as a power storage device in which a plurality of the lithium secondary batteries are assembled. One embodiment of a power storage device is shown in FIG. In FIG. 2, the power storage device 30 includes a plurality of power storage units 20. Each power storage unit 20 includes a plurality of lithium secondary batteries 1. The power storage device 30 can be mounted as a power source for vehicles such as an electric vehicle (EV), a hybrid vehicle (HEV), and a plug-in hybrid vehicle (PHEV).

（実施例１〜３）
＜リチウム過剰型リチウム遷移金属複合酸化物Ａの作製＞
硫酸コバルト７水和物７．０４ｇ、硫酸ニッケル６水和物１０．５３ｇ及び硫酸マンガン５水和物３２．６０ｇを秤量し、これらの全量をイオン交換水２００ｍｌに溶解させ、Ｃｏ：Ｎｉ：Ｍｎのモル比が１２．５：２０．０：６７．５となる１．０Ｍの硫酸塩水溶液を作製した。一方、２Ｌの反応槽に７５０ｍｌのイオン交換水を注ぎ、ＣＯ２ガスを３０ｍｉｎバブリングさせることにより、イオン交換水中にＣＯ２を溶解させた。反応槽の温度を５０℃（±２℃）に設定し、攪拌モーターを備えたパドル翼を用いて反応槽内を７００ｒｐｍの回転速度で攪拌しながら、前記硫酸塩水溶液を３ｍｌ／ｍｉｎの速度で滴下した。ここで、滴下の開始から終了までの間、１．０Ｍの炭酸ナトリウム及び０．２Ｍのアンモニアを含有する水溶液を適宜滴下することにより、反応槽中のｐＨが常に８．０（±０．０５）を保つように制御した。滴下終了後、反応槽内の攪拌をさらに１ｈ継続した。攪拌の停止後、１２ｈ以上静置した。 (Examples 1-3)
<Preparation of lithium-excess type lithium transition metal composite oxide A>
7.04 g of cobalt sulfate heptahydrate, 10.53 g of nickel sulfate hexahydrate and 32.60 g of manganese sulfate pentahydrate were weighed, and all of these were dissolved in 200 ml of ion-exchanged water, and Co: Ni: Mn A 1.0 M aqueous sulfate solution having a molar ratio of 12.5: 20.0: 67.5 was prepared. On the other hand, 750 ml of ion exchange water was poured into a 2 L reaction tank, and CO 2 gas was bubbled for 30 minutes to dissolve CO 2 in the ion exchange water. The temperature of the reaction vessel was set to 50 ° C. (± 2 ° C.), and the aqueous sulfate solution was stirred at a rate of 3 ml / min while stirring the inside of the reaction vessel at a rotational speed of 700 rpm using a paddle blade equipped with a stirring motor. It was dripped. Here, during the period from the start to the end of the dropwise addition, an aqueous solution containing 1.0 M sodium carbonate and 0.2 M ammonia is appropriately dropped, so that the pH in the reaction tank is always 8.0 (± 0.05). ) Was controlled. After completion of the dropwise addition, stirring in the reaction vessel was continued for 1 hour. After the stirring was stopped, the mixture was allowed to stand for 12 hours or more.

次に、吸引ろ過装置を用いて、反応槽内に生成した共沈炭酸塩の粒子を分離し、さらにイオン交換水を用いて２００ｍｌによる洗浄を１回としたときに、５回の洗浄を行う条件で粒子に付着しているナトリウムイオンを適度に洗浄除去し、電気炉を用いて、空気雰囲気中、常圧下、８０℃にて乾燥させた。その後、粒径を揃えるために、瑪瑙製自動乳鉢で数分間粉砕した。このようにして、共沈炭酸塩前駆体を作製した。   Next, using a suction filtration device, the coprecipitated carbonate particles generated in the reaction vessel are separated, and further, washing is performed 5 times when 200 ml is washed once with ion-exchanged water. Sodium ions adhering to the particles under conditions were washed and removed appropriately, and dried in an air atmosphere at 80 ° C. in an air atmosphere using an electric furnace. Then, in order to arrange | equalize a particle size, it grind | pulverized for several minutes with the smoked automatic mortar. In this way, a coprecipitated carbonate precursor was produced.

前記共沈炭酸塩前駆体２．２７８ｇに、炭酸リチウム０．９７０ｇを加え、瑪瑙製自動乳鉢を用いてよく混合し、Ｌｉ：（Ｃｏ，Ｎｉ，Ｍｎ）のモル比が１３０：１００である混合粉体を調製した。ペレット成型機を用いて、６ＭＰａの圧力で成型し、直径２５ｍｍのペレットとした。ペレット成型に供した混合粉体の量は、想定する最終生成物の質量が２ｇとなるように換算して決定した。前記ペレット１個を全長約１００ｍｍのアルミナ製ボートに載置し、箱型電気炉（型番：ＡＭＦ２０）に設置し、空気雰囲気中、常圧下、常温から８５０℃まで１０時間かけて昇温し、８５０℃で４ｈ焼成した。前記箱型電気炉の内部寸法は、縦１０ｃｍ、幅２０ｃｍ、奥行き３０ｃｍであり、幅方向２０ｃｍ間隔に電熱線が入っている。焼成後、ヒーターのスイッチを切り、アルミナ製ボートを炉内に置いたまま自然放冷した。この結果、炉の温度は５時間後には約２００℃程度にまで低下するが、その後の降温速度はやや緩やかである。一昼夜経過後、炉の温度が１００℃以下となっていることを確認してから、ペレットを取り出し、粒径を揃えるために、瑪瑙製自動乳鉢で数分間粉砕した。このようにして、実施例１の小粒径のリチウム過剰型リチウム遷移金属複合酸化物Ａ１に係るＬｉ１．１３Ｃｏ０．１１Ｎｉ０．１７Ｍｎ０．５９Ｏ２を作製した。このリチウム遷移金属複合酸化物が、エックス線回折測定より、α−ＮａＦｅＯ２構造を有していることを確認した。Ｎａの含有量は２１００ｐｐｍであり、後述する方法で測定した平均粒子径（Ｄ５０）は６μｍであり、ピーク微分細孔容積は１．１５ｍｍ３／（ｇ・ｎｍ）であった。 Add 0.970 g of lithium carbonate to 2.278 g of the coprecipitated carbonate precursor and mix well using a smoked automatic mortar, and the molar ratio of Li: (Co, Ni, Mn) is 130: 100 A powder was prepared. Using a pellet molding machine, molding was performed at a pressure of 6 MPa to obtain pellets having a diameter of 25 mm. The amount of the mixed powder subjected to pellet molding was determined by conversion so that the mass of the assumed final product was 2 g. One pellet was placed on an alumina boat having a total length of about 100 mm, placed in a box-type electric furnace (model number: AMF20), and heated in an air atmosphere at normal pressure to 850 ° C. over 10 hours. Calcination was performed at 850 ° C. for 4 hours. The box-type electric furnace has internal dimensions of 10 cm in length, 20 cm in width, and 30 cm in depth, and heating wires are inserted at intervals of 20 cm in the width direction. After firing, the heater was turned off and allowed to cool naturally with the alumina boat placed in the furnace. As a result, the temperature of the furnace decreases to about 200 ° C. after 5 hours, but the subsequent temperature decrease rate is somewhat moderate. After the passage of day and night, it was confirmed that the furnace temperature was 100 ° C. or lower, and then the pellets were taken out and pulverized for several minutes in a smoked automatic mortar in order to make the particle diameter uniform. In this way, Li 1.13 Co 0.11 Ni 0.17 Mn 0.59 O 2 related to the small particle size lithium-excess lithium transition metal composite oxide A1 of Example 1 was produced. This lithium transition metal composite oxide was confirmed to have an α-NaFeO 2 structure by X-ray diffraction measurement. The Na content was 2100 ppm, the average particle size (D 50 ) measured by the method described later was 6 μm, and the peak differential pore volume was 1.15 mm 3 / (g · nm).

＜ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂの作製＞
硫酸コバルト７水和物１８．７７ｇ、硫酸ニッケル６水和物１７．５６ｇ及び硫酸マンガン５水和物１６．１０ｇを秤量し、これらの全量をイオン交換水２００ｍｌに溶解させ、Ｃｏ：Ｎｉ：Ｍｎのモル比が１：１：１となる１．０Ｍの硫酸塩水溶液を作製した。一方、２Ｌの反応槽に７５０ｍｌのイオン交換水を注ぎ、Ａｒガスを３０ｍｉｎバブリングさせることにより、イオン交換水中の溶存酸素を脱気した。反応槽の温度を５０℃（±２℃）に設定し、攪拌モーターを備えたパドル翼を用いて反応槽内を７００ｒｐｍの回転速度で攪拌しながら、前記硫酸塩水溶液を３ｍｌ／ｍｉｎの速度で滴下した。ここで、滴下の開始から終了までの間、４．０Ｍの水酸化ナトリウム及び０．５Ｍのアンモニアを含有する水溶液を適宜滴下することにより、反応槽中のｐＨが常に１１．０（±０．０５）を保つように制御した。滴下終了後、反応槽内の攪拌をさらに３ｈ継続した。攪拌の停止後、１２ｈ以上静置した。 <Preparation of LiMeO type 2 lithium transition metal composite oxide B>
18.77 g of cobalt sulfate heptahydrate, 17.56 g of nickel sulfate hexahydrate and 16.10 g of manganese sulfate pentahydrate were weighed, and all of these were dissolved in 200 ml of ion-exchanged water, and Co: Ni: Mn A 1.0 M aqueous sulfate solution with a molar ratio of 1: 1: 1 was prepared. On the other hand, 750 ml of ion-exchanged water was poured into a 2 L reaction tank, and Ar gas was bubbled for 30 minutes to deaerate dissolved oxygen in the ion-exchanged water. The temperature of the reaction vessel was set to 50 ° C. (± 2 ° C.), and the aqueous sulfate solution was stirred at a rate of 3 ml / min while stirring the inside of the reaction vessel at a rotational speed of 700 rpm using a paddle blade equipped with a stirring motor. It was dripped. Here, during the period from the start to the end of the dropping, an aqueous solution containing 4.0 M sodium hydroxide and 0.5 M ammonia is appropriately dropped, so that the pH in the reaction tank is always 11.0 (± 0.0. 05). After completion of the dropping, stirring in the reaction vessel was continued for 3 hours. After the stirring was stopped, the mixture was allowed to stand for 12 hours or more.

次に、吸引ろ過装置を用いて、反応槽内に生成した共沈水酸化物の粒子を分離し、さらにイオン交換水を用いて２００ｍｌによる洗浄を１回としたときに、５回の洗浄を行う条件で粒子に付着しているナトリウムイオンを適度に洗浄除去し、電気炉を用いて、空気雰囲気中、常圧下、８０℃にて乾燥させた。その後、粒径を揃えるために、瑪瑙製自動乳鉢で数分間粉砕した。このようにして、共沈水酸化物前駆体を作製した。   Next, using a suction filtration device, the coprecipitated hydroxide particles produced in the reaction vessel are separated, and further, washing is performed 5 times when the washing with 200 ml is performed once using ion-exchanged water. Sodium ions adhering to the particles under conditions were washed and removed appropriately, and dried in an air atmosphere at 80 ° C. in an air atmosphere using an electric furnace. Then, in order to arrange | equalize a particle size, it grind | pulverized for several minutes with the smoked automatic mortar. In this way, a coprecipitated hydroxide precursor was produced.

前記共沈水酸化物前駆体１．８９８ｇに、水酸化リチウム一水和物０．８９６ｇを加え、瑪瑙製自動乳鉢を用いてよく混合し、Ｌｉ／Ｍｅ（Ｃｏ，Ｎｉ，Ｍｎ）のモル比（前記共沈水酸化物前駆体に対して混合した水酸化リチウムのモル比）が１．０である混合粉体を調製した。ペレット成型機を用いて、６ＭＰａの圧力で成型し、直径２５ｍｍのペレットとした。ペレット成型に供した混合粉体の量は、想定する最終生成物の質量が２ｇとなるように換算して決定した。前記ペレット１個を全長約１００ｍｍのアルミナ製ボートに載置し、箱型電気炉（型番：ＡＭＦ２０）に設置し、空気雰囲気中、常圧下、常温から９００℃まで１０時間かけて昇温し、９００℃で４ｈ焼成した。前記箱型電気炉の内部寸法は、縦１０ｃｍ、幅２０ｃｍ、奥行き３０ｃｍであり、幅方向２０ｃｍ間隔に電熱線が入っている。焼成後、ヒーターのスイッチを切り、アルミナ製ボートを炉内に置いたまま自然放冷した。この結果、炉の温度は５時間後には約２００℃程度にまで低下するが、その後の降温速度はやや緩やかである。一昼夜経過後、炉の温度が１００℃以下となっていることを確認してから、ペレットを取り出し、粒径を揃えるために、瑪瑙製自動乳鉢で数分間粉砕した。このようにして、実施例１の中粒径のＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ１に係るＬｉＣｏ０．３３Ｎｉ０．３３Ｍｎ０．３３Ｏ２を作製した。後述する方法で測定した平均粒子径（Ｄ５０）は１０μｍであった。 To 1.898 g of the coprecipitated hydroxide precursor, 0.896 g of lithium hydroxide monohydrate is added and mixed well using a smoked automatic mortar, and the molar ratio of Li / Me (Co, Ni, Mn) ( A mixed powder in which the molar ratio of lithium hydroxide mixed with the coprecipitated hydroxide precursor was 1.0 was prepared. Using a pellet molding machine, molding was performed at a pressure of 6 MPa to obtain pellets having a diameter of 25 mm. The amount of the mixed powder subjected to pellet molding was determined by conversion so that the mass of the assumed final product was 2 g. One pellet was placed on an alumina boat having a total length of about 100 mm, placed in a box-type electric furnace (model number: AMF20), heated in air at atmospheric pressure and normal temperature to 900 ° C. over 10 hours, Firing was performed at 900 ° C. for 4 hours. The box-type electric furnace has internal dimensions of 10 cm in length, 20 cm in width, and 30 cm in depth, and heating wires are inserted at intervals of 20 cm in the width direction. After firing, the heater was turned off and allowed to cool naturally with the alumina boat placed in the furnace. As a result, the temperature of the furnace decreases to about 200 ° C. after 5 hours, but the subsequent temperature decrease rate is somewhat moderate. After the passage of day and night, it was confirmed that the furnace temperature was 100 ° C. or lower, and then the pellets were taken out and pulverized for several minutes in a smoked automatic mortar in order to make the particle diameter uniform. In this manner, LiCo 0.33 Ni 0.33 Mn 0.33 O 2 related to the LiMeO 2 type lithium transition metal composite oxide B1 having a medium particle size of Example 1 was produced. The average particle size (D 50 ) measured by the method described later was 10 μm.

上記のように作製したリチウム過剰型リチウム遷移金属複合酸化物Ａ１：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ１を、それぞれ、質量比率８０：２０、６５：３５、及び５０：５０で混合して、実施例１、実施例２、及び実施例３に係る混合活物質を作製した。 Lithium-rich lithium transition metal composite oxide A1: LiMeO 2 type lithium transition metal composite oxide B1 prepared as described above was mixed at mass ratios of 80:20, 65:35, and 50:50, respectively. Mixed active materials according to Example 1, Example 2, and Example 3 were produced.

（実施例４）
リチウム遷移金属複合酸化物Ａの作製工程において、焼成温度を８５０℃から８７５℃に変更し、ピーク微分細孔容積が１．０２ｍｍ３／（ｇ・ｎｍ）のリチウム過剰型リチウム遷移金属複合酸化物Ａ２を作製した他は、実施例１と同様にして、実施例４に係る混合活物質を作製した。 Example 4
In the production process of the lithium transition metal composite oxide A, the calcination temperature was changed from 850 ° C. to 875 ° C., and the lithium-rich lithium transition metal composite oxide having a peak differential pore volume of 1.02 mm 3 / (g · nm) A mixed active material according to Example 4 was produced in the same manner as in Example 1 except that A2 was produced.

（実施例５）
リチウム遷移金属複合酸化物Ａの作製工程において、焼成温度を８５０℃から９００℃に変更し、ピーク微分細孔容積が０．８５ｍｍ３／（ｇ・ｎｍ）のリチウム過剰型リチウム遷移金属複合酸化物Ａ３を作製した他は、実施例１と同様にして、実施例５に係る混合活物質を作製した。 (Example 5)
In the production process of the lithium transition metal composite oxide A, the calcination temperature was changed from 850 ° C. to 900 ° C., and the lithium excess type lithium transition metal composite oxide having a peak differential pore volume of 0.85 mm 3 / (g · nm) A mixed active material according to Example 5 was produced in the same manner as in Example 1 except that A3 was produced.

（実施例６）
実施例１のリチウム遷移金属複合酸化物Ｂの作製工程において、原料水溶液滴下終了後の反応槽内の攪拌継続時間を３ｈから８ｈに変更し、中粒径のＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ２を作製した。後述する方法で測定した平均粒子径（Ｄ５０）は１２μｍであった。
リチウム過剰型リチウム遷移金属複合酸化物Ａ１と、上記のように作製したＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ２を、質量比率８０：２０で混合した他は、実施例１と同様にして、実施例６に係る混合活物質を作製した。 (Example 6)
In the production process of the lithium transition metal composite oxide B of Example 1, the stirring duration in the reaction vessel after completion of dropping of the raw material aqueous solution was changed from 3 h to 8 h, and a medium particle size LiMeO 2 type lithium transition metal composite oxide was changed. B2 was produced. The average particle diameter (D 50 ) measured by the method described later was 12 μm.
The same as in Example 1 except that the lithium-excess type lithium transition metal composite oxide A1 and the LiMeO 2 type lithium transition metal composite oxide B2 prepared as described above were mixed at a mass ratio of 80:20. A mixed active material according to Example 6 was prepared.

（比較例１）
リチウム遷移金属複合酸化物Ｂ１を混合しない他は、実施例１と同様にして、比較例１に係る活物質を作製した。 (Comparative Example 1)
An active material according to Comparative Example 1 was produced in the same manner as in Example 1 except that the lithium transition metal composite oxide B1 was not mixed.

（比較例２及び３）
リチウム過剰型リチウム遷移金属複合酸化物Ａ１：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ１の混合比率（質量比率）を、それぞれ、３５：６５、及び２０：８０に変更した他は、実施例１と同様にして、比較例２、及び比較例３に係る混合活物質を作製した。 (Comparative Examples 2 and 3)
Example 1 except that the mixing ratio (mass ratio) of the lithium-excess type lithium transition metal composite oxide A1: LiMeO 2 type lithium transition metal composite oxide B1 was changed to 35:65 and 20:80, respectively. Similarly, mixed active materials according to Comparative Example 2 and Comparative Example 3 were produced.

（比較例４）
リチウム過剰型リチウム遷移金属複合酸化物Ａ１を混合しない他は、実施例１と同様にして、比較例４に係る活物質を作製した。 (Comparative Example 4)
An active material according to Comparative Example 4 was produced in the same manner as in Example 1 except that the lithium-excess type lithium transition metal composite oxide A1 was not mixed.

（比較例５）
リチウム遷移金属複合酸化物Ａの作製工程において、焼成温度を８５０℃から９２５℃に変更し、ピーク微分細孔容積が０．６５ｍｍ３／（ｇ・ｎｍ）のリチウム過剰型リチウム遷移金属複合酸化物Ａ４を作製した他は、実施例１と同様にして、比較例５に係る混合活物質を作製した。 (Comparative Example 5)
In the production process of the lithium transition metal composite oxide A, the calcination temperature was changed from 850 ° C. to 925 ° C., and the lithium-rich lithium transition metal composite oxide having a peak differential pore volume of 0.65 mm 3 / (g · nm) A mixed active material according to Comparative Example 5 was produced in the same manner as in Example 1 except that A4 was produced.

（比較例６）
リチウム遷移金属複合酸化物Ａの作製工程において、以下に記載するように作製した共沈水酸化物前駆体を用い、ピーク微分細孔容積が０．５５ｍｍ３／（ｇ・ｎｍ）のリチウム過剰型リチウム遷移金属複合酸化物Ａ５を作製した他は、実施例１と同様にして、比較例６に係る混合活物質を作製した。 (Comparative Example 6)
In the production process of the lithium transition metal composite oxide A, a lithium-excess type lithium having a peak differential pore volume of 0.55 mm 3 / (g · nm) using a coprecipitated hydroxide precursor produced as described below. A mixed active material according to Comparative Example 6 was produced in the same manner as in Example 1 except that the transition metal composite oxide A5 was produced.

硫酸コバルト７水和物７．０４ｇ、硫酸ニッケル６水和物１０．５３ｇ及び硫酸マンガン５水和物３２．６０ｇを秤量し、これらの全量をイオン交換水２００ｍｌに溶解させ、Ｃｏ：Ｎｉ：Ｍｎのモル比が１２．５：２０．０：６７．５となる１．０Ｍの硫酸塩水溶液を作製した。一方、２Ｌの反応槽に７５０ｍｌのイオン交換水を注ぎ、Ａｒガスを３０ｍｉｎバブリングさせることにより、イオン交換水中の溶存酸素を脱気した。反応槽の温度を５０℃（±２℃）に設定し、攪拌モーターを備えたパドル翼を用いて反応槽内を７００ｒｐｍの回転速度で攪拌しながら、前記硫酸塩水溶液を３ｍｌ／ｍｉｎの速度で滴下した。ここで、滴下の開始から終了までの間、４．０Ｍの水酸化ナトリウム及び０．５Ｍのアンモニアを含有する水溶液を適宜滴下することにより、反応槽中のｐＨが常に１１．０（±０．０５）を保つように制御した。滴下終了後、反応槽内の攪拌をさらに１．５ｈ継続した。攪拌の停止後、１２ｈ以上静置した。   7.04 g of cobalt sulfate heptahydrate, 10.53 g of nickel sulfate hexahydrate and 32.60 g of manganese sulfate pentahydrate were weighed, and all of these were dissolved in 200 ml of ion-exchanged water, and Co: Ni: Mn A 1.0 M aqueous sulfate solution having a molar ratio of 12.5: 20.0: 67.5 was prepared. On the other hand, 750 ml of ion-exchanged water was poured into a 2 L reaction tank, and Ar gas was bubbled for 30 minutes to deaerate dissolved oxygen in the ion-exchanged water. The temperature of the reaction vessel was set to 50 ° C. (± 2 ° C.), and the aqueous sulfate solution was stirred at a rate of 3 ml / min while stirring the inside of the reaction vessel at a rotational speed of 700 rpm using a paddle blade equipped with a stirring motor. It was dripped. Here, during the period from the start to the end of the dropping, an aqueous solution containing 4.0 M sodium hydroxide and 0.5 M ammonia is appropriately dropped, so that the pH in the reaction tank is always 11.0 (± 0.0. 05). After completion of the dropwise addition, stirring in the reaction vessel was continued for 1.5 hours. After stopping the stirring, the mixture was allowed to stand for 12 hours or more.

次に、吸引ろ過装置を用いて、反応槽内に生成した共沈水酸化の粒子を分離し、さらにイオン交換水を用いて２００ｍｌによる洗浄を１回としたときに、５回の洗浄を行う条件で粒子に付着しているナトリウムイオンを適度に洗浄除去し、電気炉を用いて、空気雰囲気中、常圧下、８０℃にて乾燥させた。その後、粒径を揃えるために、瑪瑙製自動乳鉢で数分間粉砕した。このようにして、共沈水酸化物前駆体を作製した。   Next, using a suction filtration device, the coprecipitated hydroxylated particles generated in the reaction vessel are separated, and when washing with 200 ml is performed once using ion-exchanged water, conditions for performing washing 5 times The sodium ions adhering to the particles were appropriately washed and removed, and dried at 80 ° C. under normal pressure in an air atmosphere using an electric furnace. Then, in order to arrange | equalize a particle size, it grind | pulverized for several minutes with the smoked automatic mortar. In this way, a coprecipitated hydroxide precursor was produced.

（比較例７）
実施例１のリチウム遷移金属複合酸化物Ａの作製工程において、原料水溶液滴下終了後の反応槽内の攪拌継続時間を１ｈから５ｈに変更し、中粒径のリチウム過剰型リチウム遷移金属複合酸化物Ａ６を作製した。後述する方法で測定した平均粒子径（Ｄ５０）は１２μｍ、ピーク微分細孔容積は１．０８ｍｍ３／（ｇ・ｎｍ）であった。
リチウム過剰型リチウム遷移金属複合酸化物Ａ６を使用し、リチウム遷移金属複合酸化物Ｂを混合しない他は、実施例１と同様にして、比較例７に係る活物質を作製した。 (Comparative Example 7)
In the production process of the lithium transition metal composite oxide A of Example 1, the stirring duration in the reaction vessel after the dropping of the raw material aqueous solution was changed from 1 h to 5 h, so that the medium-sized lithium-excess lithium transition metal composite oxide A6 was produced. The average particle diameter (D 50 ) measured by the method described later was 12 μm, and the peak differential pore volume was 1.08 mm 3 / (g · nm).
An active material according to Comparative Example 7 was produced in the same manner as in Example 1 except that the lithium-excess type lithium transition metal composite oxide A6 was used and the lithium transition metal composite oxide B was not mixed.

（比較例８〜１０）
実施例１のリチウム遷移金属複合酸化物Ｂの作製工程において、原料水溶液滴下終了後の反応槽内の攪拌継続時間を３ｈから１．５ｈに変更し、小粒径のリチウム遷移金属複合酸化物Ｂ３を作製した。後述する方法で測定した平均粒子径（Ｄ５０）は６μｍであった。
リチウム過剰型リチウム遷移金属複合酸化物Ａ６：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ３を、それぞれ、質量比率８０：２０、６５：３５、及び５０：５０で混合して、比較例８、比較例９、及び比較例１０に係る活物質を作製した。 (Comparative Examples 8 to 10)
In the production process of the lithium transition metal composite oxide B of Example 1, the stirring duration in the reaction vessel after completion of dropping of the raw material aqueous solution was changed from 3 h to 1.5 h, and the lithium transition metal composite oxide B3 having a small particle size was changed. Was made. The average particle diameter (D 50 ) measured by the method described later was 6 μm.
Lithium-excess type lithium transition metal composite oxide A6: LiMeO 2 type lithium transition metal composite oxide B3 were mixed at a mass ratio of 80:20, 65:35, and 50:50, respectively, and Comparative Example 8 and Comparative Example 9 and an active material according to Comparative Example 10 were produced.

（比較例１１〜１３）
リチウム過剰型リチウム遷移金属複合酸化物Ａ１：リチウム過剰型リチウム遷移金属複合酸化物Ａ６を、それぞれ、質量比率８０：２０、６５：３５、及び５０：５０で混合して、比較例１１、比較例１２，及び比較例１３に係る混合活物質を作製した。 (Comparative Examples 11-13)
Lithium-rich lithium transition metal composite oxide A1: Lithium-rich lithium transition metal composite oxide A6 was mixed at mass ratios of 80:20, 65:35, and 50:50, respectively, and Comparative Example 11 and Comparative Example 12, and the mixed active material which concerns on the comparative example 13 was produced.

（比較例１４）
リチウム遷移金属複合酸化物Ａの作製工程において、前記共沈炭酸塩前駆体２．１８０ｇに、炭酸リチウム１．０７１ｇを加え、瑪瑙製自動乳鉢を用いてよく混合し、Ｌｉ：（Ｃｏ，Ｎｉ，Ｍｎ）のモル比が１５０：１００である混合粉体を調製し、焼成温度を８５０℃から８２５℃に変更し、ピーク微分細孔容積が０．８８ｍｍ３／（ｇ・ｎｍ）のリチウム過剰型リチウム遷移金属複合酸化物Ａ７に係るＬｉ１．２０Ｃｏ０．１０Ｎｉ０．１６Ｍｎ０．５４Ｏ２を作製した他は、実施例１と同様にして、比較例１４に係る混合活物質を作製した。 (Comparative Example 14)
In the production process of the lithium transition metal composite oxide A, 1.071 g of lithium carbonate is added to 2.180 g of the coprecipitated carbonate precursor, and mixed well using a smoked automatic mortar, and Li: (Co, Ni, A mixed powder having a molar ratio of Mn) of 150: 100 was prepared, the calcining temperature was changed from 850 ° C. to 825 ° C., and the peak differential pore volume was 0.88 mm 3 / (g · nm). The mixed active material according to Comparative Example 14 was prepared in the same manner as in Example 1 except that Li 1.20 Co 0.10 Ni 0.16 Mn 0.54 O 2 related to the lithium transition metal composite oxide A7 was produced. Produced.

（実施例７及び８）
実施例１のリチウム遷移金属複合酸化物Ｂの作製工程において、原料水溶液滴下終了後の反応槽内の攪拌継続時間を３ｈから１０ｈに変更し、大粒径のＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ４を作製した。後述する方法で測定した平均粒子径（Ｄ５０）は１８μｍであった。
リチウム過剰型リチウム遷移金属複合酸化物Ａ１：リチウム過剰型リチウム遷移金属複合酸化物Ａ６：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ４を、それぞれ、質量比率６０：２０：２０、及び５０：２０：３０で混合して、実施例７、及び実施例８に係る混合活物質を作製した。
６μｍのリチウム過剰型リチウム遷移金属複合酸化物Ａ１と１２μｍのリチウム過剰型リチウム遷移金属複合酸化物Ａ６からなる実施例７及び８のリチウム過剰型リチウム遷移金属複合酸化物Ａの平均粒子径（Ｄ５０）は、それぞれ、７．５μｍ及び７．７μｍであった。 (Examples 7 and 8)
In the production process of the lithium transition metal composite oxide B of Example 1, the stirring duration in the reaction vessel after completion of dropping of the raw material aqueous solution was changed from 3 h to 10 h, and a large particle size LiMeO 2 type lithium transition metal composite oxide B4 was produced. The average particle diameter (D 50 ) measured by the method described later was 18 μm.
Lithium-rich lithium transition metal composite oxide A1: Lithium-rich lithium transition metal composite oxide A6: LiMeO 2 type lithium transition metal composite oxide B4, respectively, with mass ratios of 60:20:20 and 50:20:30 And mixed active materials according to Example 7 and Example 8 were produced.
Average particle diameter (D 50) of the lithium-excess lithium transition metal composite oxide A of Examples 7 and 8 comprising 6 μm lithium-excess lithium transition metal composite oxide A1 and 12 μm lithium-excess lithium transition metal composite oxide A6 ) Were 7.5 μm and 7.7 μm, respectively.

（実施例９〜１２）
リチウム過剰型リチウム遷移金属複合酸化物Ａ１：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ２：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ４を、それぞれ、質量比率８０：１０：１０、６０：２０：２０、５０：３０：２０、及び８５：５：１０で混合して、実施例９、実施例１０、実施例１１、及び実施例１２に係る混合活物質を作製した。 (Examples 9 to 12)
Lithium-excess type lithium transition metal composite oxide A1: LiMeO 2 type lithium transition metal composite oxide B2: LiMeO 2 type lithium transition metal composite oxide B4, respectively, with a mass ratio of 80:10:10, 60:20:20, The mixed active materials according to Example 9, Example 10, Example 11, and Example 12 were prepared by mixing at 50:30:20 and 85: 5: 10.

（実施例１３）
リチウム過剰型リチウム遷移金属複合酸化物Ａ１：リチウム過剰型リチウム遷移金属複合酸化物Ａ６：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ２：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ４を、質量比率６０：１０：１０：２０で混合して、実施例１３に係る混合活物質を作製した。 (Example 13)
Lithium-rich lithium transition metal composite oxide A1: Lithium-rich lithium transition metal composite oxide A6: LiMeO 2 type lithium transition metal composite oxide B2: LiMeO 2 type lithium transition metal composite oxide B4 in a mass ratio of 60:10 Was mixed at 10:20 to prepare a mixed active material according to Example 13.

（実施例１４）
実施例１のリチウム遷移金属複合酸化物Ａの作製工程において、原料水溶液滴下終了後の反応槽内の攪拌継続時間を１ｈから０．５ｈに変更し、小粒径のリチウム過剰型リチウム遷移金属複合酸化物Ａ８を作製した。後述する方法で測定した平均粒子径（Ｄ５０）は４μｍ、ピーク微分細孔容積は１．０５ｍｍ３／（ｇ・ｎｍ）であった。
実施例１のリチウム遷移金属複合酸化物Ｂの作製工程において、原料水溶液滴下終了後の反応槽内の攪拌継続時間を３ｈから１ｈに変更し、小粒径のＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ５を作製した。後述する方法で測定した平均粒子径（Ｄ５０）は４μｍであった。
リチウム過剰型リチウム遷移金属複合酸化物Ａ８：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ５：リチウム過剰型リチウム遷移金属複合酸化物Ａ６：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ４を、質量比率４８：１２：２０：２０で混合して、実施例１４に係る混合活物質を作製した。
４μｍのリチウム過剰型リチウム遷移金属複合酸化物Ａ８と１２μｍのリチウム過剰型リチウム遷移金属複合酸化物Ａ６からなるリチウム過剰型リチウム遷移金属複合酸化物Ａの平均粒子径（Ｄ５０）は、６．７５μｍであった。
４μｍのＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ５と１８μｍのＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ４からなるＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂの平均粒子径（Ｄ５０）は、９μｍであった。 (Example 14)
In the production process of the lithium transition metal composite oxide A of Example 1, the stirring continuation time in the reaction vessel after completion of dropping of the raw material aqueous solution was changed from 1 h to 0.5 h, and a small particle size lithium-excess lithium transition metal composite Oxide A8 was produced. The average particle diameter (D 50 ) measured by the method described later was 4 μm, and the peak differential pore volume was 1.05 mm 3 / (g · nm).
In the production process of the lithium transition metal composite oxide B of Example 1, the stirring duration in the reaction vessel after completion of dropping of the raw material aqueous solution was changed from 3 h to 1 h, and a small particle size LiMeO 2 type lithium transition metal composite oxide B5 was produced. The average particle diameter (D 50 ) measured by the method described later was 4 μm.
Lithium excess type lithium transition metal composite oxide A8: LiMeO 2 type lithium transition metal composite oxide B5: Lithium excess type lithium transition metal composite oxide A6: LiMeO 2 type lithium transition metal composite oxide B4, mass ratio 48:12 Was mixed at 20:20 to prepare a mixed active material according to Example 14.
The average particle diameter (D 50 ) of the lithium-excess lithium transition metal composite oxide A composed of 4 μm lithium-excess lithium transition metal composite oxide A8 and 12 μm lithium-excess lithium transition metal composite oxide A6 is 6.75 μm. Met.
The average particle diameter of LiMeO 2 type lithium transition metal composite oxide B5 and 18μm of LiMeO 2 type lithium transition metal composite oxide B4 consisting LiMeO 2 type lithium transition metal complex oxide B of 4 [mu] m (D 50) is, 9 .mu.m met It was.

（比較例１５）
リチウム過剰型リチウム遷移金属複合酸化物Ａ１：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ２：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ４を、質量比率４０：４０：２０で混合して、比較例１５に係る混合活物質を作製した。 (Comparative Example 15)
Lithium-rich lithium transition metal composite oxide A1: LiMeO 2 type lithium transition metal composite oxide B2: LiMeO 2 type lithium transition metal composite oxide B4 was mixed at a mass ratio of 40:40:20, Such a mixed active material was produced.

（比較例１６）
ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ３：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ２：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ４を、質量比率６０：２０：２０で混合して、比較例１６に係る混合活物質を作製した。 (Comparative Example 16)
LiMeO 2 type lithium transition metal composite oxide B3: LiMeO 2 type lithium transition metal composite oxide B2: LiMeO 2 type lithium transition metal composite oxide B4 was mixed at a mass ratio of 60:20:20. Such a mixed active material was produced.

（実施例１５）
実施例１のリチウム遷移金属複合酸化物Ｂの作製工程において、原料水溶液滴下終了後の反応槽内の攪拌継続時間を３ｈから１２ｈに変更し、大粒径のＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ６を作製した。後述する方法で測定した平均粒子径（Ｄ５０）は２０μｍであった。
リチウム過剰型リチウム遷移金属複合酸化物Ａ１：リチウム過剰型リチウム遷移金属複合酸化物Ａ６：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ６を、それぞれ、質量比率６０：２０：２０で混合して、実施例１５に係る混合活物質を作製した。 (Example 15)
In the production process of the lithium transition metal composite oxide B of Example 1, the stirring duration in the reaction vessel after the dropping of the raw material aqueous solution was changed from 3 h to 12 h, and a large particle size LiMeO 2 type lithium transition metal composite oxide B6 was produced. The average particle diameter (D 50 ) measured by the method described later was 20 μm.
Lithium-rich lithium transition metal composite oxide A1: Lithium-rich lithium transition metal composite oxide A6: LiMeO 2 type lithium transition metal composite oxide B6 were mixed at a mass ratio of 60:20:20, respectively. A mixed active material according to No. 15 was produced.

（実施例１６）
リチウム過剰型リチウム遷移金属複合酸化物Ａ１：ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ４を、質量比率８０：２０で混合して、実施例１６に係る混合活物質を作製した。 (Example 16)
Lithium-rich lithium transition metal composite oxide A1: LiMeO 2 type lithium transition metal composite oxide B4 was mixed at a mass ratio of 80:20 to produce a mixed active material according to Example 16.

（実施例１７）
リチウム遷移金属複合酸化物Ａの作製工程において、前記共沈炭酸塩前駆体２．３０４ｇに、炭酸リチウム０．９４３ｇを加え、Ｌｉ：（Ｃｏ，Ｎｉ，Ｍｎ）のモル比が１２５：１００である混合粉体を調製し、前記混合粉体を成型したペレットの焼成温度を８００℃に変更して、ピーク微分細孔容積が１．４５ｍｍ３／（ｇ・ｎｍ）のリチウム過剰型リチウム遷移金属複合酸化物に係るＬｉ１．１１Ｃｏ０．１１Ｎｉ０．１８Ｍｎ０．６０Ｏ２を作製した他は、実施例１と同様にして、実施例１７に係る混合活物質を作製した。 (Example 17)
In the production process of the lithium transition metal composite oxide A, 0.943 g of lithium carbonate is added to 2.304 g of the coprecipitated carbonate precursor, and the molar ratio of Li: (Co, Ni, Mn) is 125: 100. A mixed powder was prepared, the firing temperature of the pellet formed with the mixed powder was changed to 800 ° C., and a lithium-excess type lithium transition metal composite having a peak differential pore volume of 1.45 mm 3 / (g · nm) A mixed active material according to Example 17 was produced in the same manner as in Example 1 except that Li 1.11 Co 0.11 Ni 0.18 Mn 0.60 O 2 related to the oxide was produced.

（実施例１８〜２１）
リチウム遷移金属複合酸化物Ａの作製工程において、前記混合粉体を成型したペレットの焼成温度を８２５℃、８５０℃、８７５℃、９００℃に変更して、それぞれ、ピーク微分細孔容積が１．２４ｍｍ３／（ｇ・ｎｍ）、１．１７ｍｍ３／（ｇ・ｎｍ）、１．０５ｍｍ３／（ｇ・ｎｍ）、０．８７ｍｍ３／（ｇ・ｎｍ）のリチウム過剰型リチウム遷移金属複合酸化物を作製した他は、実施例１７と同様にして、実施例１８〜２１に係る混合活物質を作製した。 (Examples 18 to 21)
In the production process of the lithium transition metal composite oxide A, the firing temperature of the pellet formed with the mixed powder was changed to 825 ° C., 850 ° C., 875 ° C., and 900 ° C., and the peak differential pore volume was 1. 24mm 3 / (g · nm) , 1.17mm 3 / (g · nm), 1.05mm 3 / (g · nm), lithium 0.87mm 3 / (g · nm) excess lithium transition metal composite oxide A mixed active material according to Examples 18 to 21 was produced in the same manner as Example 17 except that the product was produced.

（比較例１７〜２０）
リチウム遷移金属複合酸化物Ａの作製工程において、前記混合粉体を成型したペレットの焼成温度を９３０℃、９５０℃、９７０℃、９９０℃に変更して、それぞれ、ピーク微分細孔容積が０．８１ｍｍ３／（ｇ・ｎｍ）、０．７５ｍｍ３／（ｇ・ｎｍ）、０．６９ｍｍ３／（ｇ・ｎｍ）、０．６５ｍｍ３／（ｇ・ｎｍ）のリチウム過剰型リチウム遷移金属複合酸化物を作製した他は、実施例１７と同様にして、比較例１７〜２０に係る混合活物質を作製した。 (Comparative Examples 17-20)
In the production process of the lithium transition metal composite oxide A, the firing temperature of the pellets obtained by molding the mixed powder was changed to 930 ° C., 950 ° C., 970 ° C., and 990 ° C., and the peak differential pore volume was 0.00. 81mm 3 / (g · nm) , 0.75mm 3 / (g · nm), 0.69mm 3 / (g · nm), 0.65mm lithium-rich lithium transition metal composite oxide of 3 / (g · nm) A mixed active material according to Comparative Examples 17 to 20 was produced in the same manner as Example 17 except that the product was produced.

（実施例２２）
リチウム遷移金属複合酸化物Ａの作製工程において、前記共沈炭酸塩前駆体２．３８２ｇに、炭酸リチウム０．８６２ｇを加え、Ｌｉ：（Ｃｏ，Ｎｉ，Ｍｎ）のモル比が１１０：１００である混合粉体を調製し、ピーク微分細孔容積が１．２３ｍｍ３／（ｇ・ｎｍ）のリチウム過剰型リチウム遷移金属複合酸化物に係るＬｉ１．０５Ｃｏ０．１２Ｎｉ０．１９Ｍｎ０．６４Ｏ２
を作製した他は、実施例１と同様にして、実施例２２に係る混合活物質を作製した。 (Example 22)
In the production process of the lithium transition metal composite oxide A, 0.862 g of lithium carbonate is added to 2.382 g of the coprecipitated carbonate precursor, and the molar ratio of Li: (Co, Ni, Mn) is 110: 100. A mixed powder was prepared, and Li 1.05 Co 0.12 Ni 0.19 Mn 0.005 relating to a lithium-excess type lithium transition metal composite oxide having a peak differential pore volume of 1.23 mm 3 / (g · nm) . 64 O 2
A mixed active material according to Example 22 was prepared in the same manner as in Example 1 except that.

（実施例２３）
リチウム遷移金属複合酸化物Ａの作製工程において、前記共沈炭酸塩前駆体２．３５７ｇに、炭酸リチウム０．８８８ｇを加え、Ｌｉ：（Ｃｏ，Ｎｉ，Ｍｎ）のモル比が１１５：１００である混合粉体を調製し、ピーク微分細孔容積が１．２１ｍｍ３／（ｇ・ｎｍ）のリチウム過剰型リチウム遷移金属複合酸化物に係るＬｉ１．０７Ｃｏ０．１２Ｎｉ０．１８Ｍｎ０．６３Ｏ２を作製した他は、実施例１と同様にして、実施例２３に係る混合活物質を作製した。 (Example 23)
In the production process of the lithium transition metal composite oxide A, 0.888 g of lithium carbonate is added to 2.357 g of the coprecipitated carbonate precursor, and the molar ratio of Li: (Co, Ni, Mn) is 115: 100. A mixed powder was prepared, and Li 1.07 Co 0.12 Ni 0.18 Mn 0. 0 related to a lithium-excess type lithium transition metal composite oxide having a peak differential pore volume of 1.21 mm 3 / (g · nm) . A mixed active material according to Example 23 was produced in the same manner as in Example 1 except that 63 O 2 was produced.

（実施例２４）
リチウム遷移金属複合酸化物Ａの作製工程において、前記共沈炭酸塩前駆体２．３３２ｇに、炭酸リチウム０．９１５ｇを加え、Ｌｉ：（Ｃｏ，Ｎｉ，Ｍｎ）のモル比が１２０：１００である混合粉体を調製し、ピーク微分細孔容積が１．１９ｍｍ３／（ｇ・ｎｍ）のリチウム過剰型リチウム遷移金属複合酸化物に係るＬｉ１．０９Ｃｏ０．１１Ｎｉ０．１８Ｍｎ０．６２Ｏ２を作製した他は、実施例１と同様にして、実施例２４に係る混合活物質を作製した。 (Example 24)
In the production process of the lithium transition metal composite oxide A, 0.915 g of lithium carbonate is added to 2.332 g of the coprecipitated carbonate precursor, and the molar ratio of Li: (Co, Ni, Mn) is 120: 100. A mixed powder was prepared, and Li 1.09 Co 0.11 Ni 0.18 Mn 0. 0 related to a lithium-excess type lithium transition metal composite oxide having a peak differential pore volume of 1.19 mm 3 / (g · nm) . A mixed active material according to Example 24 was produced in the same manner as Example 1 except that 62 O 2 was produced.

（実施例２５）
リチウム遷移金属複合酸化物Ａの作製工程において、前記共沈炭酸塩前駆体２．２２３ｇに、炭酸リチウム１．０２６ｇを加え、Ｌｉ：（Ｃｏ，Ｎｉ，Ｍｎ）のモル比が１４０：１００である混合粉体を調製し、ピーク微分細孔容積が１．０２ｍｍ３／（ｇ・ｎｍ）のリチウム過剰型リチウム遷移金属複合酸化物に係るＬｉ１．１７Ｃｏ０．１１Ｎｉ０．１６Ｍｎ０．５６Ｏ２を作製した他は、実施例１と同様にして、実施例２５に係る混合活物質を作製した。 (Example 25)
In the production process of the lithium transition metal composite oxide A, 1.026 g of lithium carbonate is added to 2.223 g of the coprecipitated carbonate precursor, and the molar ratio of Li: (Co, Ni, Mn) is 140: 100. A mixed powder was prepared, and Li 1.17 Co 0.11 Ni 0.16 Mn 0. 0 related to a lithium-excess type lithium transition metal composite oxide having a peak differential pore volume of 1.02 mm 3 / (g · nm) . A mixed active material according to Example 25 was produced in the same manner as in Example 1 except that 56 O 2 was produced.

＜リチウム二次電池の作製及び評価＞
実施例１〜２５及び比較例１〜２０のそれぞれの活物質を用いて、以下の手順でリチウム二次電池（モデルセル）を作製し、電池特性を評価した。 <Production and evaluation of lithium secondary battery>
Using each active material of Examples 1 to 25 and Comparative Examples 1 to 20, lithium secondary batteries (model cells) were produced by the following procedure, and battery characteristics were evaluated.

Ｎ−メチルピロリドンを分散媒とし、活物質、アセチレンブラック（ＡＢ）及びポリフッ化ビニリデン（ＰＶｄＦ；クレハ社製、品番：＃１１００）が質量比９０：５：５の割合で混練分散されている塗布用ペーストを作製した。該塗布ペーストを厚さ２０μｍのアルミニウム（Ａ１０８５規格）箔集電体の片方の面に塗布し、乾燥し、プレス工程を経て、正極板を作製した。なお、全ての実施例及び比較例に係るリチウム二次電池同士で試験条件が同一になるように、一定面積当たりのペーストの塗布量を固形分換算で２０ｍｇ／ｃｍ２に統一することによって、単位面積当たりの活物質の質量を統一した。 Application in which N-methylpyrrolidone is used as a dispersion medium and the active material, acetylene black (AB), and polyvinylidene fluoride (PVdF; manufactured by Kureha, product number: # 1100) are kneaded and dispersed in a mass ratio of 90: 5: 5 A paste was prepared. The coating paste was applied to one surface of an aluminum (A1085 standard) foil current collector having a thickness of 20 μm, dried, and subjected to a pressing process to produce a positive electrode plate. By unitizing the coating amount of the paste per fixed area to 20 mg / cm 2 in terms of solid content so that the test conditions are the same among the lithium secondary batteries according to all Examples and Comparative Examples, the unit Standardized mass of active material per area.

ここで、前記プレス工程において、それぞれの実施例及び比較例に対して、次の手順によって、種々のプレス圧力を適用することによって、プレス後の極板厚み及び多孔度の異なる種々の正極板を作製した。まず、プレス前の正極板を２ｃｍ×２ｃｍに切り出し、平板プレス機（ＲＩＫＥＮ ＳＥＩＫＩ Ｃｏ．ＬＴＤ．製、ＣＤＭ−２０Ｍ ＴＹＰＥ Ｐ−１Ｂ）を用いて、１ＭＰａから１５ＭＰａまでの種々のプレス圧力を適用した正極板を作製した。プレス後の正極板は、ヘリウムガスを用いたピクノメトリー（Ｑｕｔａｃｈｒｏｍｅ製、ＵＬＴＲＡＰＹＣＮＯＭＥＴＥＲ１０００）により、合剤の真密度［ｇ／ｃｃ］を測定した。また、プレス後の正極板厚みと重量から、合剤密度［ｇ／ｃｃ］を算出した。正極板の多孔度は、次の式で求められる。
多孔度＝｛１−（合剤密度）／（合剤の真密度）｝×１００［％］ Here, in the pressing step, various positive pressure plates having different thicknesses and porosity after pressing are applied to the respective examples and comparative examples by applying various pressing pressures according to the following procedure. Produced. First, a positive electrode plate before pressing was cut into 2 cm × 2 cm, and various pressing pressures from 1 MPa to 15 MPa were applied using a flat plate press (manufactured by RIKEN SEIKI Co. LTD., CDM-20M TYPE P-1B). A positive electrode plate was produced. The positive electrode plate after pressing was measured for true density [g / cc] of the mixture by pycnometry using helium gas (manufactured by Quachrome, ULTRAPYCNOMETER 1000). Further, the mixture density [g / cc] was calculated from the thickness and weight of the positive electrode plate after pressing. The porosity of the positive electrode plate is obtained by the following formula.
Porosity = {1- (mixture density) / (true density of mixture)} × 100 [%]

＜限界多孔度の測定＞
プレス後の正極板（２ｃｍ×２ｃｍ）は、１２０℃の温度環境下にて１２ｈの減圧乾燥を行い、含有水分を十分に除去した後、該正方形の正極板について、対向する二辺の各中点を結ぶ線を折り目として、谷部に何も挟まず、手で半分に折り曲げ、他の対向する二辺同士を一致させた。さらに、湾曲してＵ字状となっている折り目の山部分を押圧し、正極板の表面同士を全面にわたって接触させた。次に、元の平面状に再び広げ、該正極板を可視光源の方向に向けて折り曲げ部分を目視観察し、可視光が折り曲げ部分を透過して観察されるか否かによって、正極合剤部分の破損の有無を確認した。そして、破損の認められなかった正極板のうち、最も小さい多孔度を有する正極板を決定し、該正極板の多孔度を、その実施例又は比較例における「限界多孔度」と定義した。 <Measurement of critical porosity>
The pressed positive electrode plate (2 cm × 2 cm) was dried under reduced pressure for 12 h under a temperature environment of 120 ° C., and after sufficiently removing the contained water, the square positive electrode plate A line connecting the points was a crease, and nothing was sandwiched between the valleys, and was folded in half by hand so that the other two opposite sides were matched. Further, the crest portion of the fold that was curved and formed into a U shape was pressed to bring the surfaces of the positive electrode plates into contact with each other over the entire surface. Next, it is spread again to the original flat shape, the positive electrode plate is directed toward the visible light source, the bent portion is visually observed, and the positive electrode mixture portion is determined depending on whether or not visible light is observed through the bent portion. The presence or absence of damage was confirmed. And the positive electrode plate which has the smallest porosity was determined among the positive electrode plates by which damage was not recognized, and the porosity of this positive electrode plate was defined as "limit porosity" in the Example or a comparative example.

正極の単独挙動を正確に観察する目的のため、対極、即ち負極には金属リチウムをニッケル箔集電体に密着させて用いた。ここで、リチウム二次電池の容量が負極によって制限されないよう、負極には十分な量の金属リチウムを配置した。   For the purpose of accurately observing the single behavior of the positive electrode, metallic lithium was used in close contact with the nickel foil current collector for the counter electrode, that is, the negative electrode. Here, a sufficient amount of metallic lithium was disposed on the negative electrode so that the capacity of the lithium secondary battery was not limited by the negative electrode.

電解液として、エチレンカーボネート（ＥＣ）／エチルメチルカーボネート（ＥＭＣ）／ジメチルカーボネート（ＤＭＣ）が体積比６：７：７である混合溶媒に濃度が１ｍｏｌ／ｌとなるようにＬｉＰＦ６を溶解させた溶液を用いた。セパレータとして、ポリアクリレートで表面改質したポリプロピレン製の微孔膜を用いた。外装体には、ポリエチレンテレフタレート（１５μｍ）／アルミニウム箔（５０μｍ）／金属接着性ポリプロピレンフィルム（５０μｍ）からなる金属樹脂複合フィルムを用い、正極端子及び負極端子の開放端部が外部露出するように電極を収納し、前記金属樹脂複合フィルムの内面同士が向かい合った融着代を注液孔となる部分を除いて気密封止し、前記電解液を注液後、注液孔を封止した。 As an electrolytic solution, LiPF 6 was dissolved in a mixed solvent in which ethylene carbonate (EC) / ethyl methyl carbonate (EMC) / dimethyl carbonate (DMC) had a volume ratio of 6: 7: 7 so that the concentration was 1 mol / l. The solution was used. As the separator, a polypropylene microporous film whose surface was modified with polyacrylate was used. A metal resin composite film made of polyethylene terephthalate (15 μm) / aluminum foil (50 μm) / metal-adhesive polypropylene film (50 μm) is used for the exterior body, and the electrodes are exposed so that the open ends of the positive electrode terminal and the negative electrode terminal are exposed to the outside. The metal resin composite film was hermetically sealed with the fusion allowance where the inner surfaces of the metal resin composite films faced each other except for the portion serving as the injection hole, and the injection hole was sealed after the electrolyte solution was injected.

以上の手順にて作製されたリチウム二次電池は、２５℃の下、初期充放電工程に供した。充電は、電流０．１ＣｍＡ、電圧４．６Ｖの定電流定電圧充電とし、充電終止条件は電流値が１／６に減衰した時点とした。放電は、電流０．１ＣｍＡ、終止電圧２．０Ｖの定電流放電とした。この充放電を２サイクル行った。ここで、充電後及び放電後にそれぞれ３０分の休止過程を設けた。このようにして、実施例１〜２５及び比較例１〜２０に係るリチウム二次電池を完成した。   The lithium secondary battery produced by the above procedure was subjected to an initial charge / discharge process at 25 ° C. Charging was performed at a constant current and a constant voltage with a current of 0.1 CmA and a voltage of 4.6 V, and the charge termination condition was when the current value attenuated to 1/6. The discharge was a constant current discharge with a current of 0.1 CmA and a final voltage of 2.0 V. This charge / discharge was performed for two cycles. Here, a pause process of 30 minutes was provided after charging and after discharging, respectively. Thus, the lithium secondary battery which concerns on Examples 1-25 and Comparative Examples 1-20 was completed.

完成したリチウム二次電池について、３サイクの充放電を行った。電圧制御は、全て、正極電位に対して行った。この充放電サイクルの条件は、充電電圧を４．４５Ｖとしたことを除いては、前記初期充放電工程の条件と同一である。全てのサイクルにおいて、充電後及び放電後に、３０分の休止時間を設定した。この３サイクルの充放電試験における、３サイクル目の放電容量を０．１Ｃ放電容量として記録した。   The completed lithium secondary battery was charged and discharged for 3 cycles. All voltage control was performed on the positive electrode potential. The conditions for this charge / discharge cycle are the same as the conditions for the initial charge / discharge step, except that the charge voltage is 4.45V. In all cycles, a 30 minute rest period was set after charging and after discharging. The discharge capacity at the third cycle in this three-cycle charge / discharge test was recorded as a 0.1 C discharge capacity.

＜活物質におけるリチウム遷移金属複合酸化物の粒子径及びピーク微分容積の測定＞
実施例１〜２５及び比較例１〜２０の活物質におけるリチウム遷移金属複合酸化物の平均粒子径（Ｄ５０）及びピーク微分細孔容積の測定を、試験電池における電極（正極板）中における活物質を採取することで行った。
放電状態にて解体した電極を取り出し、ＤＭＣを用いて電極に付着した電解液をよく洗浄した。その後、アルミニウム箔集電体（基板）上の合剤を採取し、この合剤を前述の小型電気炉を用いて６００℃で４時間焼成することで導電剤であるカーボンおよび結着剤であるＰＶｄＦバインダーを除去し、混合活物質のみを得た。その後、分級を行い、平均粒子径の異なる２つの活物質（リチウム過剰型リチウム遷移金属複合酸化物Ａ及びＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ）を分離した。なお、比較例１、４及び７は混合活物質ではなかった。比較例１１〜１３はリチウム遷移金属複合酸化物Ａのみの混合活物質、比較例１６はリチウム遷移金属複合酸化物Ｂのみの混合活物質であった。 <Measurement of particle diameter and peak differential volume of lithium transition metal composite oxide in active material>
The average particle diameter (D 50 ) and peak differential pore volume of the lithium transition metal composite oxide in the active materials of Examples 1 to 25 and Comparative Examples 1 to 20 were measured in the active electrode (positive electrode plate) in the test battery. This was done by collecting the material.
The electrode disassembled in the discharged state was taken out, and the electrolyte solution adhering to the electrode was thoroughly washed using DMC. Thereafter, the mixture on the aluminum foil current collector (substrate) is collected, and this mixture is baked at 600 ° C. for 4 hours using the above-mentioned small electric furnace, thereby being carbon as a conductive agent and a binder. The PVdF binder was removed to obtain only the mixed active material. Thereafter, classification was performed to separate two active materials having different average particle sizes (lithium-excess type lithium transition metal composite oxide A and LiMeO 2 type lithium transition metal composite oxide B). Comparative Examples 1, 4 and 7 were not mixed active materials. Comparative Examples 11 to 13 were mixed active materials containing only lithium transition metal composite oxide A, and Comparative Example 16 was a mixed active material containing only lithium transition metal composite oxide B.

次の条件及び手順に沿って、上記のようにして分離したリチウム過剰型リチウム遷移金属複合酸化物Ａ及びＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂの粒度分布測定を行った。測定装置には日機装社製Microtrac（型番：MT3000）を用いた。前記測定装置は、光学台、試料供給部及び制御ソフトを搭載したコンピューターを備えており、光学台にはレーザー光透過窓を有する湿式セルが設置される。測定原理は、測定対象試料が分散溶媒中に分散している分散液が循環している湿式セルにレーザー光を照射し、測定試料からの散乱光分布を粒度分布に変換する方式である。前記分散液は試料供給部に蓄えられ、ポンプによって湿式セルに循環供給される。前記試料供給部は、常に超音波振動が加えられている。今回の測定では、分散溶媒として水を用いた。又、測定制御ソフトにはMicrotrac DHS for Win98 (MT3000)を使用した。前記測定装置に設定入力する「物質情報」については、溶媒の「屈折率」として１．３３を設定し、「透明度」として「透過（TRANSPARENT）」を選択し、「球形粒子」として「非球形」を選択した。試料の測定に先立ち、「Set Zero」操作を行う。「Set zero」操作は、粒子からの散乱光以外の外乱要素（ガラス、ガラス壁面の汚れ、ガラス凹凸など）が後の測定に与える影響を差し引くための操作であり、試料供給部に分散溶媒である水のみを入れ、湿式セルに分散溶媒である水のみが循環している状態でバックグラウンド操作を行い、バックグラウンドデータをコンピューターに記憶させる。続いて「Sample LD (Sample Loading)」操作を行う。Sample LD操作は、測定時に湿式セルに循環供給される分散液中の試料濃度を最適化するための操作であり、測定制御ソフトの指示に従って試料供給部に測定対象試料を手動で最適量に達するまで投入する操作である。続いて、「測定」ボタンを押すことで測定操作が行われる。前記測定操作を２回繰り返し、その平均値として測定結果がコンピューターから出力される。測定結果は、粒度分布ヒストグラム、並びに、Ｄ１０、Ｄ５０及びＤ９０の各値（Ｄ１０、Ｄ５０及びＤ９０は、二次粒子の粒度分布における累積体積がそれぞれ１０％、５０％及び９０％となる粒度）として取得される。
電極作製時のプレス工程で活物質粒子の一部が割れることがある。従って、電極から活物質を採取して活物質粒子の粒径を求める場合、割れた活物質の存在が測定結果に影響を与えないよう留意すべきである。電極中の割れた活物質の存在状態は、走査型電子顕微鏡（ＳＥＭ）観察で確認できる。
なお、実施例１３において、Ｄ５０が１２μｍのリチウム過剰型リチウム遷移金属複合酸化物Ａ６とＤ５０が１２μｍのＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ２は分級できなかったので、この比率は、活物質粉末混合時の１：１とした。また、実施例１４において、Ｄ５０が４μｍのリチウム過剰型リチウム遷移金属複合酸化物Ａ８とＤ５０が４μｍのＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ５は分級できなかったので、この比率は、活物質粉末混合時の８：２とした。 In accordance with the following conditions and procedures, the particle size distribution of the lithium-excess type lithium transition metal composite oxide A and LiMeO 2 type lithium transition metal composite oxide B separated as described above was measured. Microtrac (model number: MT3000) manufactured by Nikkiso Co., Ltd. was used as a measuring device. The measurement apparatus includes an optical bench, a sample supply unit, and a computer equipped with control software. A wet cell having a laser light transmission window is installed on the optical bench. The measurement principle is a method in which a wet cell in which a dispersion liquid in which a sample to be measured is dispersed in a dispersion solvent circulates is irradiated with laser light, and the scattered light distribution from the measurement sample is converted into a particle size distribution. The dispersion is stored in a sample supply unit and circulated and supplied to a wet cell by a pump. The sample supply unit is always subjected to ultrasonic vibration. In this measurement, water was used as a dispersion solvent. Moreover, Microtrac DHS for Win98 (MT3000) was used for the measurement control software. For the “substance information” to be set and input to the measuring apparatus, 1.33 is set as the “refractive index” of the solvent, “TRANSPARENT” is selected as the “transparency”, and “non-spherical” is selected as the “spherical particle”. Was selected. Prior to sample measurement, perform “Set Zero” operation. The “Set zero” operation is an operation to subtract the influence of disturbance elements other than the scattered light from the particles (glass, dirt on the glass wall, glass irregularities, etc.) on subsequent measurements. A background operation is performed in a state where only certain water is added and only water as a dispersion solvent is circulating in the wet cell, and the background data is stored in the computer. Next, perform the “Sample LD (Sample Loading)” operation. The Sample LD operation is an operation for optimizing the sample concentration in the dispersion that is circulated and supplied to the wet cell during measurement, and manually reaches the optimum amount of the sample to be measured in the sample supply unit according to the instructions of the measurement control software. It is an operation to throw up. Subsequently, the measurement operation is performed by pressing the “Measure” button. The measurement operation is repeated twice, and the measurement result is output from the computer as the average value. Measurement results, the particle size distribution histogram, and, D 10, D 50 and the value of D 90 (D 10, D 50 and D 90 10% cumulative volume in the particle size distribution of secondary particles each of 50% and 90 % Granularity).
Part of the active material particles may be broken during the pressing process during electrode production. Therefore, when the active material is collected from the electrode to determine the particle size of the active material particles, it should be noted that the presence of the broken active material does not affect the measurement result. The presence state of the cracked active material in the electrode can be confirmed by observation with a scanning electron microscope (SEM).
In Examples 13, since D 50 is 12 [mu] m lithium-rich lithium transition metal composite oxide A6 and D 50 is 12 [mu] m LiMeO 2 type lithium transition metal composite oxide of B2 was not classified, this ratio is active It was set to 1: 1 when the substance powder was mixed. Further, in Example 14, the D 50 of the lithium-rich lithium transition metal composite oxide A8 and D 50 are LiMeO 2 type lithium transition metal composite oxide B5 of 4μm of 4μm could not be classified, this ratio is active It was set to 8: 2 at the time of substance powder mixing.

ピーク微分細孔容積の測定には、Quantachrome社製の「autosorb iQ」及び制御・解析ソフト「ASiQwin」を用いた。測定対象の試料（上記のようにして分離したリチウム過剰型リチウム遷移金属複合酸化物Ａ）１．００ｇを測定用のサンプル管に入れ、１２０℃にて１２ｈ真空乾燥することで、測定試料中の水分を十分に除去した。次に、液体窒素を用いた窒素ガス吸着法により、相対圧力Ｐ／Ｐ０（Ｐ０＝約７７０ｍｍＨｇ）が０から１の範囲内で吸着側および脱離側の等温線を測定した。そして、脱離側の等温線を用いてＢＪＨ法により計算することにより細孔分布を評価し、ピーク微分細孔容積を求めた。   For the measurement of the peak differential pore volume, “autosorb iQ” manufactured by Quantachrome and control / analysis software “ASiQwin” were used. 1.00 g of a sample to be measured (lithium-excess type lithium transition metal composite oxide A separated as described above) is placed in a sample tube for measurement, and vacuum-dried at 120 ° C. for 12 hours, so that Water was removed sufficiently. Next, the adsorption side and desorption side isotherms were measured by a nitrogen gas adsorption method using liquid nitrogen within a relative pressure P / P0 (P0 = about 770 mmHg) range of 0 to 1. And pore distribution was evaluated by calculating by BJH method using the desorption side isotherm, and the peak differential pore volume was obtained.

実施例１〜２５及び比較例１〜２０に係る活物質について、平均粒子径（Ｄ５０）、ピーク微分細孔容積、限界多孔度の測定結果、上記の活物質をそれぞれ用いたリチウム二次電池の試験結果を表１〜表３に示す。
なお、表１〜表３においては、「リチウム過剰型リチウム遷移金属複合酸化物Ａ」を「ＬＲ」と略記し、「ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ」を「ＮＣＭ」）と略記した。 For the active material according to Examples 1 to 25 and Comparative Examples 1 to 20, an average particle diameter (D 50), the peak differential pore volume, measured results of the critical porosity, lithium secondary batteries using the above active material, respectively Tables 1 to 3 show the test results.
In Tables 1 to 3, “lithium-excess type lithium transition metal composite oxide A” is abbreviated as “LR”, and “LiMeO 2 type lithium transition metal composite oxide B” is abbreviated as “NCM”). .

Figure 2016119288
Figure 2016119288

Figure 2016119288
Figure 2016119288

Figure 2016119288
Figure 2016119288

表１〜表３より、リチウム過剰型リチウム遷移金属複合酸化物Ａ（ＬＲ）とＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ（ＮＣＭ）の混合活物質であって、ＬＲを混合活物質物中に５０〜８５質量％含有し、ＬＲは、平均粒子径がＮＣＭの平均粒子径よりも小さく、かつ、ピーク微分細孔容積が０．８５ｍｍ３／（ｇ・ｎｍ）以上である混合活物質を正極に用いた実施例１〜２５のリチウム二次電池は、ＬＲのみを正極活物質とする比較例１及び７のリチウム二次電池と比較して、放電容量は遜色なく、正極の限界多孔度が顕著に改善されていることがわかる。また、実施例１〜２５のリチウム二次電池は、ＮＣＭのみを正極活物質とする比較例４及び１６のリチウム二次電池と比較して、限界多孔度はやや大きくなるが、放電容量が顕著に向上していることがわかる。 From Tables 1 to 3, it is a mixed active material of lithium-excess type lithium transition metal composite oxide A (LR) and LiMeO 2 type lithium transition metal composite oxide B (NCM), and LR is mixed into the mixed active material. 50 to 85% by mass, LR is a positive electrode of a mixed active material having an average particle size smaller than the average particle size of NCM and a peak differential pore volume of 0.85 mm 3 / (g · nm) or more. Compared with the lithium secondary batteries of Comparative Examples 1 and 7 in which only the LR was used as the positive electrode active material, the lithium secondary batteries of Examples 1 to 25 used for the discharge capacity were inferior and the critical porosity of the positive electrode was It can be seen that there is a marked improvement. In addition, the lithium secondary batteries of Examples 1 to 25 have a slightly higher limit porosity than the lithium secondary batteries of Comparative Examples 4 and 16 using only NCM as the positive electrode active material, but the discharge capacity is remarkable. It can be seen that there is an improvement.

これに対して、リチウム過剰型リチウム遷移金属複合酸化物Ａ（ＬＲ）の含有量が、混合活物質物中の５０質量％未満の場合（比較例２、３及び１５）には、実施例１〜２５と比較して、正極の限界多孔度は同程度であるが、放電容量が大きく低下する。
混合活物質中のリチウム過剰型リチウム遷移金属複合酸化物Ａ（ＬＲ）のピーク微分細孔容積が０．８５ｍｍ３／（ｇ・ｎｍ）未満の場合（比較例５、６及び１７〜２０）には、実施例１〜２５と比較して、正極の限界多孔度は同程度か小さいが、放電容量が大きく低下する。
混合活物質であっても、リチウム遷移金属複合酸化物Ａ（ＬＲ）の平均粒子径が、ＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ（ＮＣＭ）の平均粒子径よりも大きい場合（比較例８〜１０）は、ＬＲのみを正極活物質とする場合（比較例７）と比較して、正極の限界多孔度が顕著には改善されない。
粒子径の異なるリチウム遷移金属複合酸化物の混合物を活物質とする混合活物質であっても、リチウム過剰型リチウム遷移金属複合酸化物Ａ（ＬＲ）同士の混合物である場合（比較例１１〜１３）は、正極の限界多孔度が改善されない。
粒子径の小さいリチウム過剰型リチウム遷移金属複合酸化物Ａ（ＬＲ）と粒子径の大きいＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ（ＮＣＭ）の混合物を活物質とする混合活物質であっても、ＬＲの遷移金属Ｍｅ１に対するＬｉのモル比Ｌｉ／Ｍｅ１が１．５である場合（比較例１４）は、Ｌｉ／Ｍｅ１が１．１〜１．４である実施例１〜２５と比較して、放電容量が同程度か低く、正極の限界多孔度が顕著には改善されない。したがって、本発明においては、１．１≦モル比Ｌｉ／Ｍｅ１＜１．５とすることが好ましい。 On the other hand, when the content of the lithium-excess type lithium transition metal composite oxide A (LR) is less than 50% by mass in the mixed active material (Comparative Examples 2, 3 and 15), Example 1 Compared with ˜25, the positive porosity has the same degree of porosity, but the discharge capacity is greatly reduced.
When the peak differential pore volume of the lithium-excess type lithium transition metal composite oxide A (LR) in the mixed active material is less than 0.85 mm 3 / (g · nm) (Comparative Examples 5, 6 and 17 to 20) Compared with Examples 1-25, although the limiting porosity of a positive electrode is comparable or small, discharge capacity falls large.
Even if it is a mixed active material, the average particle diameter of lithium transition metal composite oxide A (LR) is larger than the average particle diameter of LiMeO 2 type lithium transition metal composite oxide B (NCM) (Comparative Examples 8 to 10) does not significantly improve the critical porosity of the positive electrode as compared with the case where only LR is used as the positive electrode active material (Comparative Example 7).
Even if it is a mixed active material using a mixture of lithium transition metal composite oxides having different particle diameters as an active material, it is a mixture of lithium-excess lithium transition metal composite oxides A (LR) (Comparative Examples 11 to 13). ) Does not improve the critical porosity of the positive electrode.
Even if it is a mixed active material using a mixture of lithium-excess type lithium transition metal composite oxide A (LR) having a small particle size and LiMeO 2 type lithium transition metal composite oxide B (NCM) having a large particle size as an active material, When the molar ratio Li / Me1 of Li to the transition metal Me1 is 1.5 (Comparative Example 14), compared with Examples 1 to 25 where Li / Me1 is 1.1 to 1.4, The discharge capacity is comparable or low, and the critical porosity of the positive electrode is not significantly improved. Therefore, in the present invention, it is preferable that 1.1 ≦ molar ratio Li / Me1 <1.5.

また、表２より、粒子径が６μｍ以下である小粒径のリチウム過剰型リチウム遷移金属複合酸化物Ａ（ＬＲ）を前記混合活物質物中に４８〜８０質量％含有させ、粒子径が１８μｍ以上である大粒径のＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ（ＮＣＭ）を、前記混合活物質中に１０〜３０質量％含有させることにより、放電容量が向上すると共に、顕著に限界多孔度が改善されることがわかる（実施例７〜１１、１３〜１６参照）。特に、粒子径が６μｍ以下のリチウム過剰型リチウム遷移金属複合酸化物Ａ（ＬＲ）を前記混合活物質物中に４８〜８０質量％含有させ、粒子径が６μｍを超え、１８μｍ未満のリチウム過剰型リチウム遷移金属複合酸化物Ａ（ＬＲ）及び／又はＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ（ＮＣＭ）を含有させ、さらに、粒子径が１８μｍ以上のＬｉＭｅＯ２型リチウム遷移金属複合酸化物Ｂ（ＮＣＭ）を、前記混合活物質中に１０〜３０質量％含有させることにより、顕著に限界多孔度が改善されることがわかる（実施例７〜１１、１３〜１５参照）。 Further, from Table 2, 48 to 80% by mass of the lithium-excess type lithium transition metal composite oxide A (LR) having a small particle diameter of 6 μm or less is contained in the mixed active material, and the particle diameter is 18 μm. By containing 10-30% by mass of LiMeO 2 type lithium transition metal composite oxide B (NCM) having a large particle size as described above in the mixed active material, the discharge capacity is improved and the critical porosity is remarkably increased. (See Examples 7 to 11 and 13 to 16). Particularly, the lithium-excess lithium transition metal composite oxide A (LR) having a particle diameter of 6 μm or less is contained in the mixed active material in an amount of 48 to 80% by mass, and the particle diameter is more than 6 μm and less than 18 μm. contain a lithium transition metal complex oxide a (LR) and / or LiMeO 2 type lithium transition metal complex oxide B (NCM), further, type 2 lithium transition metal composite oxide LiMeO particle size of more than 18 [mu] m B (NCM ) Is contained in the mixed active material in an amount of 10 to 30% by mass, the critical porosity is remarkably improved (see Examples 7 to 11 and 13 to 15).

上記「リチウム二次電池の作製及び評価」の欄には、正極合剤組成や正極集電体への塗布量を具体的に記載した。しかしながら、正極合剤組成や塗布量は製造しようとするリチウム二次電池の設計毎に相違しうる。これに伴って、本発明の範囲と対応する限界多孔度や０．１Ｃ容量の数値範囲も、リチウム二次電池の設計毎に相違し得る。本発明の技術的範囲への属否は、特許請求の範囲に記載した事項との対比のみによって判断すべきである。   In the column “Preparation and Evaluation of Lithium Secondary Battery”, the composition of the positive electrode mixture and the amount applied to the positive electrode current collector are specifically described. However, the composition of the positive electrode mixture and the coating amount may differ depending on the design of the lithium secondary battery to be manufactured. Along with this, the limit porosity corresponding to the range of the present invention and the numerical range of the 0.1 C capacity may be different for each design of the lithium secondary battery. Whether the present invention belongs to the technical scope should be determined only by comparison with the matters described in the claims.

（符号の説明）
１ リチウム二次電池
２ 電極群
３ 電池容器
４ 正極端子
４’ 正極リード
５ 負極端子
５’ 負極リード
２０ 蓄電ユニット
３０ 蓄電装置 (Explanation of symbols)
DESCRIPTION OF SYMBOLS 1 Lithium secondary battery 2 Electrode group 3 Battery container 4 Positive electrode terminal 4 'Positive electrode lead 5 Negative electrode terminal 5' Negative electrode lead 20 Power storage unit 30 Power storage device

本発明の「リチウム過剰型」活物質と「ＬｉＭｅＯ２型」活物質を混合した混合活物質を用いることにより、リチウム二次電池の正極における単極電気化学特性と充填性（低多孔度）を両立させることができるので、このリチウム二次電池は、ハイブリッド自動車用、電気自動車用のリチウム二次電池として有用である。 By using a mixed active material obtained by mixing the “lithium-excess type” active material and the “LiMeO 2 type” active material of the present invention, the monopolar electrochemical characteristics and the filling property (low porosity) in the positive electrode of the lithium secondary battery can be obtained. The lithium secondary battery is useful as a lithium secondary battery for hybrid vehicles and electric vehicles because it can be made compatible.

Claims (8)

α−ＮａＦｅＯ２構造を有し、遷移金属Ｍｅ１としてＣｏ、Ｎｉ及びＭｎを含有し、１＜モル比Ｌｉ／Ｍｅ１＜１．５、モル比Ｍｎ／Ｍｅ１＞０．５であるリチウム遷移金属複合酸化物Ａと、組成式ＬｉＭｅ２Ｏ２（但し、Ｍｅ２はＣｏ、Ｎｉ及びＭｎを含む遷移金属、０＜モル比Ｍｎ／Ｍｅ２≦０．５）で表されるリチウム遷移金属複合酸化物Ｂの混合物を活物質とするリチウム二次電池用混合活物質であって、前記リチウム遷移金属複合酸化物Ａを前記混合物中に５０〜８５質量％含有し、前記リチウム遷移金属複合酸化物Ａは、平均粒子径が前記リチウム遷移金属複合酸化物Ｂの平均粒子径よりも小さく、かつ、窒素ガス吸着法を用いた吸着等温線からＢＪＨ法で求めた微分細孔容積が最大値を示す細孔径が３０〜４０ｎｍの範囲で、ピーク微分細孔容積が０．８５ｍｍ３／（ｇ・ｎｍ）以上であることを特徴とするリチウム二次電池用混合活物質。 Lithium transition metal composite oxidation having an α-NaFeO 2 structure, containing Co, Ni and Mn as transition metals Me1 and 1 <molar ratio Li / Me1 <1.5 and molar ratio Mn / Me1> 0.5 active and objects a, formula LiMe2O 2 (where, Me2 is Co, transition metal containing Ni and Mn, 0 <mole ratio Mn / Me2 ≦ 0.5) a mixture of a lithium transition metal composite oxide represented by B It is a mixed active material for a lithium secondary battery, and contains 50 to 85 mass% of the lithium transition metal composite oxide A in the mixture. The lithium transition metal composite oxide A has an average particle size. The pore diameter is smaller than the average particle diameter of the lithium transition metal composite oxide B, and the pore diameter is 30 to 40 nm where the differential pore volume determined by the BJH method from the adsorption isotherm using the nitrogen gas adsorption method is the maximum value. In a range Mixed active material for a lithium secondary battery, characterized by a peak differential pore volume is 0.85mm 3 / (g · nm) or more. 前記リチウム遷移金属複合酸化物Ａとして、粒子径が６μｍ以下の粒子を前記混合物中に４８〜８０質量％含有することを特徴とする請求項１に記載のリチウム二次電池用混合活物質。   2. The mixed active material for a lithium secondary battery according to claim 1, wherein the lithium transition metal composite oxide A contains 48 to 80 mass% of particles having a particle size of 6 μm or less in the mixture. 前記リチウム遷移金属複合酸化物Ａは、平均粒子径が８μｍ以下であることを特徴とする請求項１又は２に記載のリチウム二次電池用混合活物質。   3. The mixed active material for a lithium secondary battery according to claim 1, wherein the lithium transition metal composite oxide A has an average particle size of 8 μm or less. 前記リチウム遷移金属複合酸化物Ｂは、平均粒子径が９μｍ以上であることを特徴とする請求項１〜３のいずれか１項に記載のリチウム二次電池用混合活物質。   4. The mixed active material for a lithium secondary battery according to claim 1, wherein the lithium transition metal composite oxide B has an average particle size of 9 μm or more. 前記リチウム遷移金属複合酸化物Ｂとして、粒子径が１８μｍ以上の粒子を、前記混合物中に１０〜３０質量％含有することを特徴とする請求項１〜４のいずれか１項に記載のリチウム二次電池用混合活物質。   5. The lithium secondary metal composite oxide according to claim 1, wherein the lithium transition metal composite oxide B contains 10 to 30% by mass of particles having a particle diameter of 18 μm or more in the mixture. Mixed active material for secondary batteries. 前記リチウム遷移金属複合酸化物Ａは、組成式Ｌｉ１＋αＭｅ１１−αＯ２、１．１≦（１＋α）／（１−α）≦１．４で表されることを特徴とする請求項１〜５のいずれか１項に記載のリチウム二次電池用混合活物質。 The lithium transition metal composite oxide A is represented by a composition formula Li 1 + α Me1 1-α O 2 , 1.1 ≦ (1 + α) / (1-α) ≦ 1.4. The mixed active material for lithium secondary batteries according to any one of -5. 請求項１〜６のいずれか１項に記載のリチウム二次電池用混合活物質を含有するリチウム二次電池用正極。   The positive electrode for lithium secondary batteries containing the mixed active material for lithium secondary batteries of any one of Claims 1-6. 請求項７に記載のリチウム二次電池用正極を備えたリチウム二次電池。   A lithium secondary battery comprising the positive electrode for a lithium secondary battery according to claim 7.
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