　（実施例９～１２、比較例５～８、実施例１３～１６）
　反応槽内の雰囲気を大気雰囲気（酸素分圧：２１２７３Ｐａ）として、反応水溶液のｐＨ値を液温２５℃基準で１３．０に、アンモニア濃度を１５ｇ／Ｌに維持して、２分３０秒間の晶析を行い、核生成を行った（核生成工程）のち、反応水溶液のｐＨ値を液温２５℃基準で１１．６になるまで、２５質量％水酸化ナトリウム水溶液の供給を停止し、その後、その供給を再開して、反応水溶液のｐＨ値を液温２５℃基準で１１．６に、アンモニア濃度を１５ｇ／Ｌに維持して、３０分間の晶析を行い、給液を一旦停止し、反応槽内の雰囲気を窒素雰囲気（酸素分圧；２００Ｐａ）となるまで窒素ガスを流通させ、その後、給液を開始し、成長開始から合計で２時間の晶析を行い（粒子成長工程）、粒子成長工程後にさらに窒素ガスを流通させて、雰囲気の酸素分圧を５Ｐａとしたこと以外は、実施例１～４、比較例１～４、実施例５～８と同様の同様にして、複合水酸化物粒子を得るとともに、同様の測定を行った。その測定結果を表２に示す。(Examples 9 to 12, Comparative Examples 5 to 8, Examples 13 to 16)
The atmosphere in the reaction vessel was an atmospheric atmosphere (oxygen partial pressure: 21273 Pa), the pH value of the aqueous reaction solution was maintained at 13.0 on the basis of the liquid temperature of 25 ° C., and the ammonia concentration was maintained at 15 g / L for 2 minutes and 30 seconds. After crystallization and nucleation (nucleation step), the supply of 25% by mass aqueous sodium hydroxide is stopped until the pH value of the reaction aqueous solution becomes 11.6 based on the liquid temperature of 25 ° C. Then, the supply was resumed, the pH value of the reaction aqueous solution was maintained at 11.6 on the basis of the liquid temperature of 25 ° C., the ammonia concentration was maintained at 15 g / L, crystallization was carried out for 30 minutes, and the liquid supply was temporarily stopped. Then, nitrogen gas was circulated until the atmosphere in the reaction tank became a nitrogen atmosphere (oxygen partial pressure; 200 Pa), and then the liquid supply was started, and crystallization was performed for a total of 2 hours from the start of growth (particle growth process) Circulate nitrogen gas after the grain growth process The composite hydroxide particles were obtained in the same manner as in Examples 1 to 4, Comparative Examples 1 to 4, and Examples 5 to 8, except that the oxygen partial pressure in the atmosphere was changed to 5 Pa. Went. The measurement results are shown in Table 2.

　（比較例９、実施例１７、比較例１０、１１）
　晶析工程終了から洗浄工程を開始するまでの間、スラリーのｐＨ値を２５℃基準で１３．５としたこと（比較例９）以外は実施例１２と同様にして、酸素分圧を１０Ｐａとしたこと（実施例１７）、酸素分圧を５０Ｐａおよび２００Ｐａとしたこと（比較例１０、１１）以外は、実施例１６と同様にして、それぞれ複合水酸化物粒子を得るとともに、同様の測定を行った。その測定結果を表２に合わせて示す。(Comparative Example 9, Example 17, Comparative Examples 10 and 11)
From the end of the crystallization step to the start of the washing step, the oxygen partial pressure was set to 10 Pa in the same manner as in Example 12 except that the pH value of the slurry was 13.5 on the basis of 25 ° C. (Comparative Example 9). (Example 17) Except that the oxygen partial pressure was 50 Pa and 200 Pa (Comparative Examples 10 and 11), the composite hydroxide particles were obtained in the same manner as in Example 16 and the same measurement was performed. went. The measurement results are shown in Table 2.

　なお、実施例９～１２，比較例５～９，実施例１３～１７のいずれにおいても、カリウム含有量は２０質量ｐｐｍ未満であった。In Examples 9 to 12, Comparative Examples 5 to 9, and Examples 13 to 17, the potassium content was less than 20 ppm by mass.

　（総合評価）
　表１および表２より、洗浄工程の開始時点における複合水酸化物粒子を構成する金属元素の平均価数が大きくなるほど、最終的に得られる複合水酸化物粒子中のアルカリ金属の含有量、特にナトリウム含有量が大きくなることが理解される。特に、平均価数が２．４を超えると、ナトリウム単独でもその含有量が５００ｐｐｍを超えてしまうことが理解される。(Comprehensive evaluation)
From Table 1 and Table 2, as the average valence of the metal element constituting the composite hydroxide particles at the start of the washing step increases, the content of alkali metal in the finally obtained composite hydroxide particles, particularly It is understood that the sodium content is increased. In particular, when the average valence exceeds 2.4, it is understood that the content of sodium alone exceeds 500 ppm.

　したがって、洗浄工程の開始時点において、金属元素の平均価数を２．４以下に制御した状態で複合水酸化物粒子を洗浄することにより、アルカリ金属、特にナトリウムを十分に除去でき、複合水酸化物粒子中に残存するアルカリ金属の含有量を低減させうることが理解される。Therefore, at the start of the cleaning process, by washing the composite hydroxide particles in a state where the average valence of the metal element is controlled to 2.4 or less, alkali metal, particularly sodium can be sufficiently removed, and composite hydroxide It is understood that the content of alkali metal remaining in the product particles can be reduced.

　このため、本発明によれば、結晶中に残存するアルカリ金属の含有量が少ない正極活物質を得るための前駆体として複合水酸化物粒子が提供されること、および、本発明の複合水酸化物粒子を前駆体とする正極活物質を正極材料として用いることで、電池特性の低下やばらつきが抑制された二次電池を製造することが可能となることが理解される。Therefore, according to the present invention, composite hydroxide particles are provided as a precursor for obtaining a positive electrode active material with a small content of alkali metal remaining in the crystal, and the composite hydroxide of the present invention It is understood that by using a positive electrode active material having a product particle as a precursor as a positive electrode material, it is possible to manufacture a secondary battery in which deterioration and variation in battery characteristics are suppressed.

Claims

　中和剤として水酸化ナトリウムを用いた晶析反応により、一般式（Ａ）：Ｎｉ_xＭｎ_yＣｏ_zＭ_t（ＯＨ）_2+a（ｘ＋ｙ＋ｚ＋ｔ＝１、０．３≦ｘ≦０．７、０．１≦ｙ≦０．５５、０≦ｚ≦０．４、０≦t≦０．１、０≦ａ≦０．５、Ｍは、Ｍｇ、Ｃａ、Ａｌ、Ｔｉ、Ｖ、Ｃｒ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ、Ｔａ、Ｗから選択される１種以上の元素）で表されるニッケルマンガン複合水酸化物粒子を含むスラリーを得る晶析工程と、
　前記ニッケルマンガン複合水酸化物粒子中の金属元素の平均価数を２．４以下に制御した状態で、該ニッケルマンガン複合水酸化物粒子を洗浄する洗浄工程と、
を備える、ことを特徴とするニッケルマンガン複合水酸化物粒子の製造方法。The crystallization reaction using sodium hydroxide as a neutralizing agent, the general formula_{_{(A): Ni x Mn y}} Co z M t (OH) 2 + a (x + y + z + t = 1,0.3 ≦ x ≦ 0.7, 0.1 ≦ y ≦ 0.55, 0 ≦ z ≦ 0.4, 0 ≦ t ≦ 0.1, 0 ≦ a ≦ 0.5, M is Mg, Ca, Al, Ti, V, Cr, Zr Crystallization step of obtaining a slurry containing nickel manganese composite hydroxide particles represented by Nb, Mo, Hf, Ta, W).
A washing step of washing the nickel manganese composite hydroxide particles in a state where the average valence of the metal element in the nickel manganese composite hydroxide particles is controlled to 2.4 or less;
A method for producing nickel manganese composite hydroxide particles, comprising:
　前記晶析工程終了から前記洗浄工程を開始するまでの間、前記スラリーを、酸素分圧を１０Ｐａ以下に制御した非酸化性雰囲気中に保持する、請求項１に記載のニッケルマンガン複合水酸化物粒子の製造方法。2. The nickel manganese composite hydroxide according to claim 1, wherein the slurry is maintained in a non-oxidizing atmosphere in which an oxygen partial pressure is controlled to 10 Pa or less from the end of the crystallization step to the start of the cleaning step. Particle manufacturing method.
　前記晶析工程終了から前記洗浄工程を開始するまでの間、前記スラリーを、液温２５℃基準でのｐＨ値を１０．５～１３．０の範囲に制御した状態で保持する、請求項１または２に記載のニッケルマンガン複合水酸化物粒子の製造方法。2. The slurry is maintained in a state in which the pH value based on a liquid temperature of 25 ° C. is controlled in the range of 10.5 to 13.0 from the end of the crystallization step to the start of the washing step. Or the manufacturing method of the nickel manganese composite hydroxide particle | grains of 2 or 2.
　前記晶析工程終了から前記洗浄工程を開始するまでの間、前記スラリーを、大気雰囲気中で、液温２５℃基準でのｐＨ値を１０．５～１３．０の範囲に制御した状態で保持し、かつ、該保持時間を１０時間以下とする、請求項１に記載のニッケルマンガン複合水酸化物粒子の製造方法。From the end of the crystallization process to the start of the washing process, the slurry is maintained in an air atmosphere in a state where the pH value based on a liquid temperature of 25 ° C. is controlled within the range of 10.5 to 13.0. And the manufacturing method of the nickel manganese composite hydroxide particle | grains of Claim 1 which makes this holding time 10 hours or less.
　前記晶析工程を、核生成用水溶液を、液温２５℃基準でのｐＨ値が１２．０～１４．０となるように制御して、酸素濃度が１容量％を超える酸化性雰囲気中で核生成を行う核生成工程と、該核生成工程において形成された核を含有する粒子成長用水溶液を、液温２５℃でのｐＨ値が１０．５～１２．０となるように制御するとともに、粒子成長工程の開始時から粒子成長工程の全体に対して０％～４０％の範囲で酸化性雰囲気から酸素濃度１容量％以下の酸素と不活性ガスの混合雰囲気に切り替えて、前記核を成長させる粒子成長工程とにより構成し、前記ニッケルマンガン複合水酸化物粒子を、微細一次粒子からなる中心部を有し、かつ、該中心部の外側に、前記微細一次粒子よりも大きな板状一次粒子からなる外殻部を有する二次粒子として得る、請求項１～４のいずれかに記載のニッケルマンガン複合水酸化物粒子の製造方法。In the crystallization step, the aqueous solution for nucleation is controlled so that the pH value on the basis of a liquid temperature of 25 ° C. is 12.0 to 14.0, in an oxidizing atmosphere in which the oxygen concentration exceeds 1% by volume. A nucleation step for nucleation and an aqueous solution for particle growth containing nuclei formed in the nucleation step are controlled so that the pH value at a liquid temperature of 25 ° C. is 10.5 to 12.0. The nuclei are switched from an oxidizing atmosphere to a mixed atmosphere of oxygen and inert gas having an oxygen concentration of 1% by volume or less in the range of 0% to 40% with respect to the whole of the particle growth process from the start of the particle growth process. The nickel-manganese composite hydroxide particles have a central part composed of fine primary particles, and the plate-like primary larger than the fine primary particles outside the central part. Secondary particle having outer shell made of particles And get method of nickel-manganese composite hydroxide particles according to any one of claims 1-4.
　一般式（Ａ）：Ｎｉ_xＭｎ_yＣｏ_zＭ_t（ＯＨ）_2+a（ｘ＋ｙ＋ｚ＋ｔ＝１、０．３≦ｘ≦０．７、０．１≦ｙ≦０．５５、０≦ｚ≦０．４、０≦t≦０．１、０≦ａ≦０．５、Ｍは、Ｍｇ、Ｃａ、Ａｌ、Ｔｉ、Ｖ、Ｃｒ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ、Ｔａ、Ｗから選択される１種以上の元素）で表され、複数の一次粒子が凝集して形成された二次粒子からなり、かつ、アルカリ金属の含有量が５００質量ｐｐｍ以下であることを特徴とする、ニッケルマンガン複合水酸化物粒子。Formula_{_{(A): Ni x Mn y}} Co z M t (OH) 2 + a (x + y + z + t = 1,0.3 ≦ x ≦ 0.7,0.1 ≦ y ≦ 0.55,0 ≦ z ≦ 0 .4, 0 ≦ t ≦ 0.1, 0 ≦ a ≦ 0.5, M is selected from Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W Nickel manganese composite water characterized by comprising secondary particles formed by agglomerating a plurality of primary particles and having an alkali metal content of 500 ppm by mass or less. Oxide particles.
　一般式（Ａ）：Ｎｉ_xＭｎ_yＣｏ_zＭ_t（ＯＨ）_2+a（ｘ＋ｙ＋ｚ＋ｔ＝１、０．３≦ｘ≦０．７、０．１≦ｙ≦０．５５、０≦ｚ≦０．４、０≦t≦０．１、０≦ａ≦０．５、Ｍは、Ｍｇ、Ｃａ、Ａｌ、Ｔｉ、Ｖ、Ｃｒ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ、Ｔａ、Ｗから選択される１種以上の元素）で表され、微細一次粒子が凝集した中心部を有し、かつ、該中心部の外側に、前記微細一次粒子よりも大きな板状一次粒子が凝集した外殻部を有する二次粒子からなり、および、アルカリ金属の含有量が５００質量ｐｐｍ以下であることを特徴とする、ニッケルマンガン複合水酸化物粒子。Formula_{_{(A): Ni x Mn y}} Co z M t (OH) 2 + a (x + y + z + t = 1,0.3 ≦ x ≦ 0.7,0.1 ≦ y ≦ 0.55,0 ≦ z ≦ 0 .4, 0 ≦ t ≦ 0.1, 0 ≦ a ≦ 0.5, M is selected from Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W 2) having a central portion in which fine primary particles are aggregated and an outer shell portion in which plate-like primary particles larger than the fine primary particles are aggregated outside the central portion. Nickel-manganese composite hydroxide particles comprising secondary particles and having an alkali metal content of 500 ppm by mass or less.
　一般式（Ｂ）：Ｎｉ_xＭｎ_yＣｏ_zＭ_t（ＯＨ）_2+a（ｘ＋ｙ＋ｚ＋ｔ＝１、０．３≦ｘ≦０．６、０．２≦ｙ≦０．４、０．１≦ｚ≦０．４、０≦t≦０．０２、０≦ａ≦０．５、Ｍは、Ｍｇ、Ｃａ、Ａｌ、Ｔｉ、Ｖ、Ｃｒ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ、Ｔａ、Ｗから選択される１種以上の元素）で表される、請求項６または７に記載のニッケルマンガン複合水酸化物粒子。Formula_{_{(B): Ni x Mn y}} Co z M t (OH) 2 + a (x + y + z + t = 1,0.3 ≦ x ≦ 0.6,0.2 ≦ y ≦ 0.4,0.1 ≦ z ≦ 0.4, 0 ≦ t ≦ 0.02, 0 ≦ a ≦ 0.5, M is selected from Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W The nickel manganese composite hydroxide particles according to claim 6 or 7, represented by: one or more elements.
　請求項５～８のいずれかに記載のニッケルマンガン複合水酸化物粒子を前駆体とするリチウムニッケルマンガン複合酸化物粒子からなることを特徴とする、非水系電解質二次電池用正極活物質。A positive electrode active material for a non-aqueous electrolyte secondary battery, comprising lithium nickel manganese composite oxide particles having the nickel manganese composite hydroxide particles according to any one of claims 5 to 8 as a precursor.