JP6442633B2 - Positive electrode active material composite for lithium ion secondary battery or positive electrode active material composite for sodium ion secondary battery, secondary battery using these, and production method thereof - Google Patents

Description

  The present invention provides a positive electrode active material composite for a lithium ion secondary battery or a positive electrode active material composite for a sodium ion secondary battery having a layered rock salt structure, which can effectively enhance the high-temperature cycle characteristics in a secondary battery, The present invention relates to a lithium ion secondary battery or a sodium ion secondary battery included as a positive electrode material, and a method for producing these positive electrode active material composites for lithium ion secondary batteries or positive electrode active material composites for sodium ion secondary batteries.

  Conventionally, lithium composite oxide has been used as a positive electrode active material capable of constituting a high-output and high-capacity lithium ion secondary battery. Such a lithium composite oxide has a layered crystal structure in which a lithium atomic layer and a transition metal atomic layer are alternately stacked via an oxygen atomic layer, and one lithium atom is included per one atom of the transition metal. It is also known to have a so-called layered rock salt structure.

  In a lithium ion secondary battery using such a lithium composite oxide as a positive electrode active material, charging / discharging is performed as lithium ions are desorbed and inserted into the lithium composite oxide, but usually the charge / discharge cycle is repeated. When the battery is used for a long time, the battery capacity may be significantly reduced. This is considered to be caused by the fact that the transition metal component of the lithium composite oxide is eluted into the electrolytic solution during charging, so that the crystal structure is easily collapsed. In particular, the higher the temperature, the greater the amount of transition metal elution and the greater the effect on cycle characteristics. In addition, when the crystal structure of the lithium composite oxide collapses, the transition metal component of the lithium composite oxide may elute into the surrounding electrolyte, which may reduce the thermal stability and impair safety.

However, for example, battery materials used for in-vehicle batteries are required to have excellent durability performance that can maintain a certain capacity or more even after a large number of charge / discharge cycles of 1000 cycles or more. Various developments have been made to meet this demand. For example, in Patent Document 1, primary particles having an average particle diameter of 1 μm to 8 μm aggregate to form secondary particles having an average particle diameter of 5 μm to 30 μm, and the porosity of the secondary particles is 30% or less. Composite oxides are disclosed. Patent Document 2 discloses a lithium composite oxide having a true density of 4.40 g / cm ^{3 to} 4.80 g / cm ³ and having a high volumetric energy density and having appropriate voids in the positive electrode active material. Further, a specific example of an electrode active material having a lithium composite oxide of a core part and a lithium composite oxide of a shell part having a composition different from that of the core part is also described.

  On the other hand, since lithium is a rare valuable substance, a sodium composite oxide that has a layered rock salt structure similar to that of lithium composite oxide and that can be charged and discharged with sodium ions instead of lithium ions has been developed. Yes. For example, Patent Document 3 discloses a sodium composite oxide having excellent cycle characteristics, including Fe, Mn, Ni, Co, or Ti.

JP 2001-85006 A International Publication No. 2014/133069 Pamphlet JP 2010-80424 A

  However, in any of the techniques described in any of these documents, it is difficult to sufficiently improve the cycle characteristics of the lithium composite oxide or the sodium composite oxide, and further improvement is required.

  Therefore, the subject of this invention is the positive electrode active material composite for lithium ion secondary batteries which can improve a high temperature cycling characteristic effectively, when it uses as a positive electrode active material of a lithium ion secondary battery or a sodium ion secondary battery. Or it is providing the positive electrode active material composite_body | complex for sodium ion secondary batteries.

  Accordingly, as a result of intensive studies, the present inventors have found that lithium composite oxide particles and lithium composite oxide secondary particles are formed on the surface and internal voids of the lithium composite oxide secondary particles made of specific lithium composite oxide particles. By compounding with a specific lithium-based polyanion particle having a specific mass ratio with respect to the particles, when used as a positive electrode material of a lithium ion secondary battery, the reaction with the electrolyte is effectively suppressed, It has been found that a positive electrode active material composite for a lithium ion secondary battery that does not cause a decrease in output even after many charge / discharge cycles is obtained.

  Further, in the surface and internal voids of the sodium composite oxide secondary particles composed of specific sodium composite oxide particles, the sodium composite oxide particles and the specific mass ratio having a specific mass ratio with respect to the sodium composite oxide secondary particles By compounding with sodium-based polyanion particles, when used as a positive electrode material for sodium ion secondary batteries, the reaction with the electrolyte is effectively suppressed, and the output decreases even after many charge / discharge cycles. It has also been found that a positive electrode active material composite for a sodium ion secondary battery can be obtained.

That is, the present invention provides the following formula (I):
LiNi _a Co _b Mn _c M ¹ _x O ₂ (I)
(In the formula (I), ^{M 1} is Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, 1 or 2 or more elements selected from Bi and Ge are shown, a, b, c, and x are 0.3 ≦ a <1, 0 <b ≦ 0.7, 0 <c ≦ 0.7, (0 ≦ x ≦ 0.3 and 3a + 3b + 3c + (valence of M ¹ ) × x = 3)
Or the following formula (II):
LiNi _d Co _e Al _f M ² _y O ₂ (II)
(In the formula (II), ^{M 2} is Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi and One or more elements selected from Ge are shown, d, e, f, and y are 0.4 ≦ d <1, 0 <e ≦ 0.6, 0 <f ≦ 0.3, 0 ≦. (Y ≦ 0.3 and 3d + 3e + 3f + (valence of M ² ) × y = 3)
In the surface and internal voids of the lithium composite oxide secondary particles (A) comprising one or more lithium composite oxide particles represented by the following formula (V):
^{_{Li s Co g Ni h M 5}} i PO 4 ··· (V)
(In the formula (V), M ⁵ represents Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. S, g, h, and i are 0.8 ≦ s ≦ 1.2, 0 ≦ g ≦ 1.2, 0 ≦ h ≦ 1.2, 0 ≦ i ≦ 0.3, g + h ≠ 0, and 0.8 ≦ (g + h + i) ≦ 1.2 And s + 2g + 2h + (the valence of M ⁵ ) × i = 3.
Or the following formula (VI):
^{_{Li t Co j Ni k M 6}} l SiO 4 ··· (VI)
(In the formula (VI), M ⁶ represents Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. T, j, k, and l are 1.6 ≦ t ≦ 2.4, 0 ≦ j ≦ 1.2, 0 ≦ k ≦ 1.2, 0 ≦ l ≦ 1.2, j + k ≠ 0, and 0.8 ≦ (j + k + l) ≦ 1.2 And t + 2j + 2k + (the valence of M ⁶ ) × l = 4 is shown.)
A lithium-based polyanion particle (B) containing at least one of cobalt and nickel and a lithium composite oxide particle, and the content of the lithium composite oxide secondary particle (A), Provided is a positive electrode active material composite for a lithium ion secondary battery having a mass ratio ((A) :( B)) of 95: 5 to 50:50 with respect to the content of the lithium-based polyanion particles (B). is there.

The present invention also provides the following formula (III):
NaNi _{a ′} Co _{b ′} Mn _{c ′} M ³ _{x ′} O ₂ (III)
(In the formula (III), ^{M 3} is Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, 1 or 2 or more elements selected from Bi and Ge, a ′, b ′, c ′ and x ′ are 0.3 ≦ a ′ <1, 0 <b ′ ≦ 0.7, 0 < (c ′ ≦ 0.7, 0 ≦ x ′ ≦ 0.3, and 3a ′ + 3b ′ + 3c ′ + (valence of M ³ ) × x ′ = 3).
Or the following formula (IV):
NaNi _{d ′} Co _{e ′} Al _{f ′} M ⁴ _{y ′} O ₂ (IV)
(In the formula (IV), M ⁴ is Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi and 1 or 2 or more elements selected from Ge, d ′, e ′, f ′, and y ′ are 0.4 ≦ d ′ <1, 0 <e ′ ≦ 0.6, and 0 <f ′. ≦ 0.3,0 ≦ y '≦ 0.3, and 3d' + 3e '+ 3f' + ( valence of ^{M 4)} shows a number satisfying × y '= 3.)
In the surface and internal voids of the sodium composite oxide secondary particles (D) composed of one or more kinds of sodium composite oxide particles represented by the following formula (VII):
Na _w Cog _′ Ni _{h ′} M ⁹ _{i ′} PO ₄ (VII)
(In the formula (VII), M ⁹ represents Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd or Gd. W, g ′, h ′ and i 'Is 0.8 ≦ w ≦ 1.2, 0 ≦ g ′ ≦ 1.2, 0 ≦ h ′ ≦ 1.2, 0 ≦ i ′ ≦ 0.3, g ′ + h ′ ≠ 0, and 0. 8 ≦ (g ′ + h ′ + i ′) ≦ 1.2 and w + 2g ′ + 2h ′ + (valence of M ⁹ ) × i ′ = 3 is shown.)
Or the following formula (VIII):
Na _x Co _{j ′} Ni _{k ′} M ¹⁰ _{l ′} SiO ₄ (VIII)
(.X shown in the formula ^{(VIII), M 10} is Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, and Nd or Gd, j ', k', and l Is 1.6 ≦ x ≦ 2.4, 0 ≦ j ′ ≦ 1.2, 0 ≦ k ′ ≦ 1.2, 0 ≦ l ′ ≦ 1.2, j ′ + k ′ ≠ 0, and 0. 8 ≦ (j ′ + k ′ + l ′) ≦ 1.2 is satisfied and x + 2j ′ + 2k ′ + (valence of M ¹⁰ ) × l ′ = 4 is indicated.)
The sodium-based polyanion particles (E) containing at least either cobalt or nickel and the sodium composite oxide particles are combined, and the content of the sodium composite oxide secondary particles (D), Provided is a positive electrode active material composite for a sodium ion secondary battery having a mass ratio ((D) :( E)) to the content of sodium-based polyanion particles (E) of 95: 5 to 50:50. is there.

  Furthermore, the present invention provides the above lithium ion secondary battery comprising a step of compositing lithium composite oxide particles and lithium-based polyanion particles (B) on the surface and internal voids of the lithium composite oxide secondary particles (A). The present invention relates to a method for producing a positive electrode active material composite.

  The present invention also provides the sodium ion secondary battery comprising a step of complexing sodium composite oxide particles and sodium-based polyanion particles (E) on the surface and internal voids of the sodium composite oxide secondary particles (D). The present invention relates to a method for producing a positive electrode active material composite.

  According to the positive electrode active material composite for a lithium ion secondary battery or the positive electrode active material composite for a sodium ion secondary battery according to the present invention, the crystal structure is prevented from collapsing while having a layered rock salt structure. In a lithium ion secondary battery or a sodium ion secondary battery obtained by using as a high temperature cycle characteristic can be effectively enhanced.

FIG. 1A is a TEM photograph of positive electrode active material composite particles for a lithium ion secondary battery obtained in Example 1. FIG. Moreover, FIG.1 (b)-(c) is the photograph of the element distribution of TEM-EDX of the cross section of the positive electrode active material composite particle for lithium ion secondary batteries obtained in Example 1, FIG.1 (b). ) Shows the distribution of Ni element, and FIG. 1C shows the distribution of P element. 2A is a TEM photograph of the positive electrode active material composite particles for a lithium ion secondary battery obtained in Example 2. FIG. FIGS. 2B to 2C are photographs of the TEM-EDX element distribution in the cross section of the positive electrode active material composite particles for lithium ion secondary battery obtained in Example 2. FIG. ) Shows the distribution of Ni element, and FIG. 2C shows the distribution of Si element.

Hereinafter, the present invention will be described in detail.
The positive electrode active material composite for a lithium ion secondary battery of the present invention has the following formula (I):
LiNi _a Co _b Mn _c M ¹ _x O ₂ (I)
(In the formula (I), ^{M 1} is Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, 1 or 2 or more elements selected from Bi and Ge are shown, a, b, c, and x are 0.3 ≦ a <1, 0 <b ≦ 0.7, 0 <c ≦ 0.7, (0 ≦ x ≦ 0.3 and 3a + 3b + 3c + (valence of M ¹ ) × x = 3)
Or the following formula (II):
LiNi _d Co _e Al _f M ² _y O ₂ (II)
(In the formula (II), ^{M 2} is Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi and One or more elements selected from Ge are shown, d, e, f, and y are 0.4 ≦ d <1, 0 <e ≦ 0.6, 0 <f ≦ 0.3, 0 ≦. (Y ≦ 0.3 and 3d + 3e + 3f + (valence of M ² ) × y = 3)
In the surface and internal voids of the lithium composite oxide secondary particles (A) comprising one or more lithium composite oxide particles represented by the following formula (V):
^{_{Li s Co g Ni h M 5}} i PO 4 ··· (V)
(In the formula (V), M ⁵ represents Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. S, g, h, and i are 0.8 ≦ s ≦ 1.2, 0 ≦ g ≦ 1.2, 0 ≦ h ≦ 1.2, 0 ≦ i ≦ 0.3, g + h ≠ 0, and 0.8 ≦ (g + h + i) ≦ 1.2 And s + 2g + 2h + (the valence of M ⁵ ) × i = 3.
Or the following formula (VI):
^{_{Li t Co j Ni k M 6}} l SiO 4 ··· (VI)
(In the formula (VI), M ⁶ represents Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. T, j, k, and l are 1.6 ≦ t ≦ 2.4, 0 ≦ j ≦ 1.2, 0 ≦ k ≦ 1.2, 0 ≦ l ≦ 1.2, j + k ≠ 0, and 0.8 ≦ (j + k + l) ≦ 1.2 And t + 2j + 2k + (the valence of M ⁶ ) × l = 4 is shown.)
A lithium-based polyanion particle (B) containing at least one of cobalt and nickel and a lithium composite oxide particle, and the content of the lithium composite oxide secondary particle (A), The mass ratio ((A) :( B)) to the content of the lithium-based polyanion particles (B) is 95: 5 to 50:50.

Moreover, the positive electrode active material composite for a sodium ion secondary battery of the present invention has the following formula (III):
NaNi _{a ′} Co _{b ′} Mn _{c ′} M ³ _{x ′} O ₂ (III)
(In the formula (III), ^{M 3} is Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, 1 or 2 or more elements selected from Bi and Ge, a ′, b ′, c ′ and x ′ are 0.3 ≦ a ′ <1, 0 <b ′ ≦ 0.7, 0 < (c ′ ≦ 0.7, 0 ≦ x ′ ≦ 0.3, and 3a ′ + 3b ′ + 3c ′ + (valence of M ³ ) × x ′ = 3).
Or the following formula (IV):
NaNi _{d ′} Co _{e ′} Al _{f ′} M ⁴ _{y ′} O ₂ (IV)
(In the formula (IV), M ⁴ is Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi and 1 or 2 or more elements selected from Ge, d ′, e ′, f ′, and y ′ are 0.4 ≦ d ′ <1, 0 <e ′ ≦ 0.6, and 0 <f ′. ≦ 0.3,0 ≦ y '≦ 0.3, and 3d' + 3e '+ 3f' + ( valence of ^{M 4)} shows a number satisfying × y '= 3.)
In the surface and internal voids of the sodium composite oxide secondary particles (D) composed of one or more kinds of sodium composite oxide particles represented by the following formula (VII):
Na _w Cog _′ Ni _{h ′} M ⁹ _{i ′} PO ₄ (VII)
(In the formula (VII), M ⁹ represents Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd or Gd. W, g ′, h ′ and i 'Is 0.8 ≦ w ≦ 1.2, 0 ≦ g ′ ≦ 1.2, 0 ≦ h ′ ≦ 1.2, 0 ≦ i ′ ≦ 0.3, g ′ + h ′ ≠ 0, and 0. 8 ≦ (g ′ + h ′ + i ′) ≦ 1.2 and w + 2g ′ + 2h ′ + (valence of M ⁹ ) × i ′ = 3 is shown.)
Or the following formula (VIII):
Na _x Co _{j ′} Ni _{k ′} M ¹⁰ _{l ′} SiO ₄ (VIII)
(.X shown in the formula ^{(VIII), M 10} is Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, and Nd or Gd, j ', k', and l Is 1.6 ≦ x ≦ 2.4, 0 ≦ j ′ ≦ 1.2, 0 ≦ k ′ ≦ 1.2, 0 ≦ l ′ ≦ 1.2, j ′ + k ′ ≠ 0, and 0. 8 ≦ (j ′ + k ′ + l ′) ≦ 1.2 is satisfied and x + 2j ′ + 2k ′ + (valence of M ¹⁰ ) × l ′ = 4 is indicated.)
The sodium-based polyanion particles (E) containing at least either cobalt or nickel and the sodium composite oxide particles are combined, and the content of the sodium composite oxide secondary particles (D), Mass ratio ((D) :( E)) with content of sodium-based polyanion particles (E) is 95: 5 to 50:50.

Lithium composite oxide (so-called Li—Ni—Co—Mn oxide, hereinafter referred to as “Li—NCM composite oxide”) particles represented by the above formula (I), and the above formula (III) Sodium composite oxide (so-called Na—Ni—Co—Mn oxide, hereinafter referred to as “Na—NCM composite oxide”). Also, Li—NCM composite oxide and Na—NCM composite oxide And a lithium nickel composite oxide represented by the above formula (II) (so-called Li-Ni-Co-Al oxide, hereinafter referred to as "Li-NCA"). And a sodium nickel composite oxide represented by the above formula (IV) (so-called Na—Ni—Co—Al oxide, hereinafter referred to as “Na—NCA composite oxide”). Also called The li-NCA based composite oxide and Na-NCA based composite oxide are collectively referred to as "NCA based composite oxide".) Particles are both particles having a layered rock salt structure.
These particles aggregate to form lithium composite oxide secondary particles (A) or sodium composite oxide secondary particles (D). Therefore, these secondary particles are also referred to as “NCA composite oxide secondary particles”, “NCA composite oxide secondary particles” and the like.

M ¹ in the above formula (I) or M ³ in the above formula (III) is Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, One or more elements selected from Sn, Ta, W, La, Ce, Pb, Bi and Ge are shown.
In the above formula (I), a, b, c and x are 0.3 ≦ a <1, 0 <b ≦ 0.7, 0 <c ≦ 0.7, 0 ≦ x ≦ 0.3, And 3a + 3b + 3c + (valence of M ¹ ) × x = 3, and a ′, b ′, c ′, x ′ in the above formula (III) are 0.3 ≦ a ′ <1, 0 < b ′ ≦ 0.7, 0 <c ′ ≦ 0.7, 0 ≦ x ′ ≦ 0.3, and 3a ′ + 3b ′ + 3c ′ + (the valence of M ³ ) × x ′ = 3 It is.

In the NCM composite oxide particles represented by the above formula (I) or formula (III), it is known that Ni, Co and Mn are excellent in electronic conductivity and contribute to battery capacity and output characteristics. Further, from the viewpoint of cycle characteristics, it is preferable that a part of the transition element is substituted with another metal element M ¹ or M ³ . By substituting with these metal elements M ¹ or M ³ , the crystal structure of the NCM composite oxide particles represented by the formula (I) or the formula (III) is stabilized. It is considered that the collapse of the crystal structure can be suppressed and excellent cycle characteristics can be realized.
Specific examples of the Li-NCM composite oxide particles represented by the above formula (I) include LiNi _0.33 Co _0.33 Mn _0.34 O ₂ , LiNi _0.8 Co _0.1 Mn _0.1 O ₂ , LiNi _0.6 Co _0.2 Mn _0.2. Examples thereof include particles composed of O ₂ , LiNi _0.2 Co _0.4 Mn _0.4 O ₂ , LiNi _0.33 Co _0.31 Mn _0.33 Mg _0.03 O ₂ , and LiNi _0.33 Co _0.31 Mn _0.33 Zn _0.03 O ₂ . Among them, when importance is attached to the discharge capacity, particles having a composition with a large amount of Ni, such as LiNi _0.8 Co _0.1 Mn _0.1 O ₂ and LiNi _0.6 Co _0.2 Mn _0.2 O ₂ , are preferable. Particles having a composition with a small amount of Ni, such as LiNi _0.33 Co _0.33 Mn _0.34 O ₂ and LiNi _0.33 Co _0.31 Mn _0.33 Mg _0.03 O _2, are preferable.
Specific examples of the Na-NCM composite oxide particles represented by the above formula (III) include NaNi _0.33 Co _0.33 Mn _0.34 O ₂ , NaNi _0.8 Co _0.1 Mn _0.1 O ₂ , NaNi _0.6 Co _0.2. Examples thereof include particles made of Mn _0.2 O ₂ , NaNi _0.2 Co _0.4 Mn _0.4 O ₂ , NaNi _0.33 Co _0.31 Mn _0.33 Mg _0.03 O ₂ , NaNi _0.33 Co _0.31 Mn _0.33 Zn _0.03 O _{2 and the} like. In particular, when the discharge capacity is important, particles having a composition with a large amount of Ni, such as NaNi _0.8 Co _0.1 Mn _0.1 O ₂ , NaNi _0.6 Co _0.2 Mn _0.2 O ₂ , are preferable, and when the cycle characteristics are important. Particles having a composition with a small amount of Ni, such as NaNi _0.33 Co _0.33 Mn _0.34 O ₂ and NaNi _0.33 Co _0.31 Mn _0.33 Mg _0.03 O ₂ are preferred.

Furthermore, two or more types of Li—NCM composite oxide particles represented by the above formula (I) having different compositions from each other have a core-shell structure Li having a core part (inside) and a shell part (surface layer part). -The NCA type complex oxide secondary particles (A) may be formed.
In addition, two or more kinds of Na—NCM composite oxide particles represented by the above formula (III) having different compositions from each other have a core-shell structure Na having a core part (inside) and a shell part (surface layer part). -The NCA type complex oxide secondary particles (D) may be formed.

By using the NCM-based composite oxide secondary particles (A) or (D) formed with this core-shell structure, NCM-based composite oxide particles with a high Ni concentration that easily elute into the electrolyte are used as the core part. Since the NCM-based complex oxide particles having a low Ni concentration can be disposed in the shell portion that is disposed and is in contact with the electrolytic solution, it is possible to further improve the suppression of deterioration in cycle characteristics and the securing of safety. At this time, the core part may be a single phase or may be composed of two or more phases having different compositions. As an aspect in which the core part is composed of two or more phases, a structure in which a plurality of phases are concentrically stacked and laminated, or a structure in which the composition changes transitionally from the surface of the core part toward the center part may be used. Good.
Furthermore, the shell part should just be formed in the outer side of a core part, may be 1 phase like a core part, and may be comprised by 2 or more phases from which a composition differs.

As the Li-NCM composite oxide secondary particles (A) formed by forming a core-shell structure with two or more types of Li-NCM composite oxide particles having different compositions, specifically, (core part) -(Shell part) is, for example, (LiNi _0.8 Co _0.1 Mn _0.1 O ₂ )-(LiNi _0.2 Co _0.4 Mn _0.4 O ₂ ), (LiNi _0.8 Co _0.1 Mn _0.1 O ₂ )-(LiNi _0.33 Co _0.33 Mn _0.34 O ₂ ), And (LiNi _0.8 Co _0.1 Mn _0.1 O ₂ ) — (LiNi _0.33 Co _0.31 Mn _0.33 Mg _0.03 O ₂ ) and the like.

Further, as the Na-NCM composite oxide secondary particles (D) formed by forming a core-shell structure with two or more kinds of Na-NCM composite oxide particles having different compositions, specifically (core part) -(Shell part) is, for example, (NaNi _0.8 Co _0.1 Mn _0.1 O ₂ )-(NaNi _0.2 Co _0.4 Mn _0.4 O ₂ ), (NaNi _0.8 Co _0.1 Mn _0.1 O ₂ )-(NaNi _0.33 Co _0.33 Mn _0.34 O ₂ ), Or (NaNi _0.8 Co _0.1 Mn _0.1 O ₂ ) — (NaNi _0.33 Co _0.31 Mn _0.33 Mg _0.03 O ₂ ) or the like.

The average particle size as the primary particles of the NCM composite oxide particles represented by the above formula (I) or formula (III) is preferably 500 nm or less, and more preferably 300 nm or less. In this way, by suppressing the average particle size as the primary particles of the NCM-based composite oxide particles to at least 500 nm or less, the expansion and contraction amount of the primary particles accompanying the insertion and desorption of lithium ions or sodium ions can be suppressed. And particle cracking can be effectively prevented. The lower limit of the average particle size of the primary particles is not particularly limited, but is preferably 50 nm or more from the viewpoint of handling.
The average particle diameter of the NCM composite oxide secondary particles (A) or (D) formed by aggregation of the primary particles is preferably 25 μm or less, more preferably 20 μm or less. When the average particle size of the secondary particles is 25 μm or less, a battery having excellent high-temperature cycle characteristics can be obtained. The lower limit of the average particle size of the secondary particles is not particularly limited, but is preferably 1 μm or more and more preferably 5 μm or more from the viewpoint of handling.
Here, the average particle diameter means an average value of measured values of the particle diameter (length of major axis) of several tens of particles in observation with an SEM or TEM electron microscope.
In the present specification, the NCM-based composite oxide secondary particles (A) or (D) include only the primary particles formed from the respective secondary particles, and are lithium-based polyanion particles (B) or sodium-based particles. Does not contain polyanion particles (E).

Li-NCM composite oxide particles represented by the above formula (I), or Na-NCM composite oxide particles represented by the above formula (III) are NCM composite oxide secondary particles (A) or When the core-shell structure is formed in (D), the average particle size as primary particles forming the core part is preferably 50 nm to 500 nm, more preferably 50 nm to 300 nm. And the average particle diameter of the core part which aggregates and forms the said primary particle becomes like this. Preferably they are 1 micrometer-25 micrometers, More preferably, they are 1 micrometer-20 micrometers.
Further, the average particle size as the primary particles of the Li-NCM composite oxide particles constituting the shell portion covering the surface of the core portion, or the average particle size as the primary particles of the Na-NCM composite oxide particles is The thickness of the shell part formed by aggregation of the primary particles is preferably 0.1 μm to 5 μm, more preferably 0. 5 nm to 500 nm, and more preferably 50 nm to 300 nm. 1 μm to 2.5 μm.

On the surface of the secondary particles (A) or (D) comprising the NCM composite oxide particles represented by the above formula (I) or formula (III), the NCM composite oxide particles and the lithium polyanion particles (B) Alternatively, since the sodium-based polyanion particles (E) are complexed and the lithium-based polyanion particles (B) or the sodium-based polyanion particles (E) are present so as to cover the surface of the secondary particles, the NCM system The elution of the metal (Ni, Co, Mn, M ¹ or M ³ ) contained in the composite oxide particles can be effectively suppressed. The internal porosity of the secondary particles (A) or (D) made of the NCM composite oxide represented by the above formula (I) or formula (III) is determined by the Li-NCM system accompanying the insertion of lithium ions or sodium ions. From the viewpoint of allowing expansion of the composite oxide or the Na-NCM composite oxide in the internal voids of the respective secondary particles, 4 volume% to 12 volume% in 100 volume% of the NCM composite oxide secondary particles. Is preferable, and 5 volume%-10 volume% are more preferable.

Next, the Li—NCA composite oxide particles represented by the formula (II) and the Na—NCA composite oxide particles represented by the formula (IV) will be described.
M ² in the above formula (II) or M ⁴ in the above formula (IV) is Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, One or more elements selected from Ta, W, La, Ce, Pb, Bi and Ge are shown.
In the above formula (II), d, e, f, and y are 0.4 ≦ d <1, 0 <e ≦ 0.6, 0 <f ≦ 0.3, 0 ≦ y ≦ 0.3, And 3d + 3e + 3f + (valence of M ² ) × y = 3, and d ′, e ′, f ′, and y ′ in the above formula (IV) are 0.4 ≦ d ′ <1, 0 < e ′ ≦ 0.6, 0 <f ′ ≦ 0.3, 0 ≦ y ′ ≦ 0.3, and 3d ′ + 3e ′ + 3f ′ + (valence of M ⁴ ) × y ′ = 3 .

The NCA-based composite oxide particles represented by the above formula (II) or formula (IV) are more battery capacity and output characteristics than the NCM-based composite oxide particles represented by the formula (I) or formula (III). Is excellent. In addition, due to the inclusion of Al, alteration due to moisture in the atmosphere hardly occurs and the safety is excellent.
Specific examples of the Li-NCA composite oxide particles represented by the above formula (II) include LiNi _0.33 Co _0.33 Al _0.34 O ₂ , LiNi _0.8 Co _0.1 Al _0.1 O ₂ , LiNi _0.8 Co _0.15 Al _0.03. Examples thereof include particles made of Mg _0.03 O ₂ , LiNi _0.8 Co _0.15 Al _0.03 Zn _0.03 O _{2, and the} like. Among these, particles made of LiNi _0.8 Co _0.15 Al _0.03 Mg _0.03 O ₂ are preferable.
Specific examples of the Na-NCA composite oxide particles represented by the above formula (IV) include, for example, NaNi _0.33 Co _0.33 Al _0.34 O ₂ , NaNi _0.8 Co _0.1 Al _0.1 O ₂ , NaNi _0.8 Co _0.15 Examples thereof include particles composed of Al _0.03 Mg _0.03 O ₂ , NaNi _0.8 Co _0.15 Al _0.03 Zn _0.03 O _{2, and the} like. Among these, particles made of NaiNi _0.8 Co _0.15 Al _0.03 Mg _0.03 O ₂ are preferable.

The average particle diameter as the primary particles of the NCA-based composite oxide represented by the above formula (II) or formula (IV), and the composite oxide secondary particles (A) formed by agglomerating the primary particles or ( The average particle diameter of D) and the internal porosity of the secondary particles are the same as those of the NCM composite oxide particles. That is, the average particle size as primary particles of the NCA-based composite oxide particles represented by the above formula (II) or formula (IV) is preferably 500 nm or less, more preferably 300 nm or less. The average particle diameter of the NCA-based composite oxide secondary particles (A) or (D) is preferably 25 μm or less, more preferably 20 μm or less. The internal porosity of the NCA-based composite oxide secondary particles (A) or (D) made of the NCA-based composite oxide represented by the above formula (II) or formula (IV) is the volume of the secondary particles. Among 100%, 4 volume%-12 volume% are preferable, and 5 volume%-10 volume% are more preferable.
By having such an average particle diameter and internal porosity, on the surface of the secondary particles (A) or (D) composed of the NCA-based composite oxide particles represented by the above formula (II) or formula (IV), NCA The composite oxide particles and the lithium polyanion particles (B) or the sodium polyanion particles (E) are combined to form the lithium polyanion particles (B) or the sodium polyanion particles (E) on the surface of the secondary particles. Therefore, the elution of the metal (Ni, Co, Al, M ² or M ⁴ ) contained in the NCA-based composite oxide particles can be effectively suppressed.

  The lithium composite oxide secondary particles (A) of the present invention include Li-NCM composite oxide particles represented by the above formula (I) and Li-NCA composite oxide particles represented by the above formula (II). May be mixed. The mixed state is that primary particles that are Li-NCM composite oxide particles represented by the above formula (I) and primary particles that are Li-NCA composite oxide particles represented by the above formula (II) coexist. Secondary particles comprising only Li-NCM composite oxide particles represented by the above formula (I) and Li-NCA represented by the above formula (II). Secondary particles consisting only of the composite oxide particles may be mixed, and further, the primary particles that are Li-NCM composite oxide particles represented by the above formula (I) and the above formula (II). Secondary particles formed by the coexistence of primary particles that are Li-NCA composite oxide particles, secondary particles composed only of Li-NCM composite oxide particles represented by the above formula (I), and the above formula ( II) and secondary particles consisting only of Li-NCA composite oxide particles represented by It may be the one. And when it is a secondary particle which consists only of Li-NCM system complex oxide particles denoted by the above-mentioned formula (I), two or more kinds of Li-NCM system complex oxide particles from which composition differs mutually make core-shell A structure may be formed.

  Further, the sodium composite oxide secondary particle (D) of the present invention comprises Na-NCM composite oxide particles represented by the above formula (III) and Na-NCA composite oxide represented by the above formula (IV). Object particles may be mixed. The mixed state is such that primary particles that are Na—NCM composite oxide particles represented by the above formula (III) and primary particles that are Na—NCA composite oxide particles represented by the above formula (IV) coexist. Secondary particles composed only of Na—NCM composite oxide particles represented by the above formula (III) and Na—NCA represented by the above formula (IV). Secondary particles consisting only of the composite oxide particles may be mixed, and further, the primary particles which are Na-NCM composite oxide particles represented by the above formula (III) and the above formula (IV). Secondary particles formed by the coexistence of primary particles that are Na-NCA composite oxide particles, secondary particles composed only of Na-NCM composite oxide particles represented by the above formula (III), and the above formula ( IV) secondary particles consisting only of Na-NCA composite oxide particles represented by It may be the one. And when it is a secondary particle which consists only of Na-NCM system complex oxide particles denoted by the above-mentioned formula (III), two or more kinds of Na-NCM system complex oxide particles from which composition differs mutually make core-shell A structure may be formed.

  NCM in the case where the NCM composite oxide particles represented by the above formula (I) or the above formula (III) and the NCA composite oxide particles represented by the above formula (II) or the above formula (IV) are mixed. The ratio (mass%) of the system composite oxide particles and the NCA system composite oxide particles may be appropriately adjusted depending on the battery characteristics to be obtained. For example, when importance is attached to rate characteristics, it is preferable to increase the proportion of the NCM composite oxide particles represented by the above formula (I) or the above formula (III). The mass ratio of the oxide particles to the NCA-based composite oxide particles (NCM-based composite oxide: NCA-based composite oxide) is preferably 99.9: 0.1 to 60:40. Further, for example, when importance is attached to battery capacity, it is preferable to increase the proportion of the NCA-based composite oxide particles represented by the above formula (II) or the above formula (IV). The mass ratio of the NCM composite oxide particles to the NCA composite oxide particles (NCM composite oxide: NCA composite oxide) is preferably 40:60 to 0.1: 99.9.

The NCM-based secondary particles (A) or (D), or the NCA-based composite oxide secondary particles (A) or (D) are embedded with water-insoluble carbon particles (C) in their internal voids, The water-insoluble carbon particles (C) may be supported on the surface.
The water-insoluble carbon particle (C) is a water-insoluble carbon material having a dissolution amount in 100 g of water at 25 ° C. of less than 0.4 g in terms of carbon atom of the water-insoluble carbon particle, and without firing or the like. It itself has conductivity. Examples of the material of the water-insoluble carbon particles (C) include one or more selected from graphite, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black. Among these, graphite is preferable from the viewpoint of handling and reducing the amount of adsorbed moisture. The graphite may be any of artificial graphite (scaly, massive, earthy, graphene) or natural graphite.

BET specific surface area of the water-insoluble carbon particles (C), from the viewpoint of effectively reducing the amount of adsorbed water is preferably ^{1m 2} / ^g~750m 2 / g, more preferably ^{3m 2} / ^g~500m 2 / g. In addition, the average particle size of the water-insoluble carbon particles (C) is well compounded with the NCM-based secondary particles (A) or (D), or the NCA-based composite oxide secondary particles (A) or (D). From the viewpoint of making it preferable, it is preferably 0.1 μm to 10 μm, more preferably 0.1 μm to 5 μm.

The amount of embedded and supported water-insoluble carbon particles (C) embedded in the internal voids of the lithium composite oxide secondary particles (A) or sodium composite oxide secondary particles (D) and supported on the surface The total amount is 0.5% by mass to 20% by mass in the positive electrode active material composite for lithium ion secondary battery or the positive electrode active material composite for sodium ion secondary battery, more preferably 0.5%. The mass is 15% by mass to 15% by mass, and more preferably 0.5% by mass to 10% by mass.
Further, the mass ratio ((A) :( C), the content of the lithium composite oxide secondary particles (A) or the sodium composite oxide secondary particles (D) and the content of the water-insoluble carbon particles (C), Or (D) :( C)) is preferably 99.9: 0.1 to 90:10, more preferably 98: 2 to 92: 8.

Next, the lithium polyanion particles (B) and the sodium polyanion particles (E) will be described.
The lithium-based polyanion particles (B) that are combined with the lithium composite oxide particles on the surface and internal voids of the lithium composite oxide secondary particles (A) are represented by the following formula (V):
^{_{Li s Co g Ni h M 5}} i PO 4 ··· (V)
(In the formula (V), M ⁵ represents Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. S, g, h, and i are 0.8 ≦ s ≦ 1.2, 0 ≦ g ≦ 1.2, 0 ≦ h ≦ 1.2, 0 ≦ i ≦ 0.3, g + h ≠ 0, and 0.8 ≦ (g + h + i) ≦ 1.2 And s + 2g + 2h + (the valence of M ⁵ ) × i = 3.
Or the following formula (VI):
^{_{Li t Co j Ni k M 6}} l SiO 4 ··· (VI)
(In the formula (VI), M ⁶ represents Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. T, j, k, and l are 1.6 ≦ t ≦ 2.4, 0 ≦ j ≦ 1.2, 0 ≦ k ≦ 1.2, 0 ≦ l ≦ 1.2, j + k ≠ 0, and 0.8 ≦ (j + k + l) ≦ 1.2 And t + 2j + 2k + (the valence of M ⁶ ) × l = 4 is shown.)
And a compound containing at least either cobalt or nickel and capable of providing good lithium ion conductivity. The lithium ion conductivity of the lithium-based polyanion particles (B) is preferably 1 × 10 ⁻⁷ S / cm or more, and more preferably 1 × 10 ⁻⁶ S / cm or more.
The lithium-based polyanion particles (B) may be combined with primary particles of the lithium composite oxide, and directly combined with a part of the secondary particles (A) formed by aggregation of the primary particles of the lithium composite oxide. It may be converted.

Specific examples of the lithium-based polyanion particles (B) represented by the above formula (V) include LiCoPO ₄ , LiCo _0.75 Ni _0.25 PO ₄ , LiCo _0.7 Ni _0.2 Mn _0.1 PO ₄ , and LiCo _0.7 Ni _0.2 Fe _0.1. Examples include PO ₄ , Li _0.9 Co _1.05 PO ₄ , Li _1.1 Co _0.95 PO ₄ , Li _1.1 Co _0.75 Ni _0.20 PO _{4, and the} like. Among these, LiCoPO ₄ or LiCo _0.7 Ni _0.2 Mn _0.1 PO ₄ is preferable.
Specific examples of the lithium-based polyanion particles (B) represented by the above formula (VI) include Li ₂ CoSiO ₄ , Li ₂ Co _0.5 Ni _0.5 SiO ₄ , and Li ₂ Co _0.4 Ni _0.4 Mn _0.2 SiO. ₄ , Li ₂ Co _0.4 Ni _0.4 Fe _0.2 SiO ₄ , Li _2.2 Co _0.9 SiO ₄ , Li _1.8 Co _1.1 SiO ₄ , Li _2.2 Co _0.5 Ni _0.4 SiO _{4 and the} like. Among these, Li ₂ CoSiO ₄ or Li ₂ Co _0.4 Ni _0.4 Mn _0.2 SiO ₄ is preferable.

  Further, the lithium-based polyanion particles (B) form a core-shell structure having a core portion (inside) and a shell portion (surface layer portion) composed of the lithium-based polyanion particles represented by the above formula (V) or (VI). It may be made.

Due to the core-shell structure of this lithium-based polyanion particle (B), a lithium-based polyanion having a high Mn content that easily elutes from the lithium-based polyanion particle (B) into the electrolyte is disposed in the core, and the shell is in contact with the electrolyte A lithium-based polyanion having a low Mn content is arranged, or a lithium-based polyanion having a high Co content that is highly toxic to the human body and the environment is arranged in the core portion. The shell portion in contact with the electrolyte solution has a low Co content. By arranging the lithium-based polyanion, it is possible to further improve the suppression of cycle characteristics due to the lithium-based polyanion particles and the securing of safety. At this time, the core part may be a single phase or may be composed of two or more phases having different compositions. As an aspect in which the core part is composed of two or more phases, a structure in which a plurality of phases are concentrically stacked and laminated, or a structure in which the composition changes transitionally from the surface of the core part toward the center part may be used. Good.
Furthermore, the shell part should just be formed in the outer side of a core part, may be 1 phase like a core part, and may be comprised by 2 or more phases from which a composition differs.

As the lithium-based polyanion particles (B) formed by forming a core-shell structure with two or more types of lithium-based polyanion particles having different compositions, specifically, (core portion)-(shell portion) is, for example, ( _{LiCoPO 4) - (LiNiPO 4)} , (LiCo 0.8 Mn 0.2 PO 4) - (LiNiPO 4), (LiCoPO 4) - (LiFe 0.3 Ni 0.7 PO 4), (Li 2 CoSiO 4) - (Li 2 NiSiO 4) , (Li ₂ Co _0.8 Mn _0.2 SiO ₄ ) — (Li ₂ NiSiO ₄ ), (Li ₂ CoSiO ₄ ) — (Li ₂ Fe _0.3 Ni _0.7 SiO ₄ ), or the like.

Further, the sodium-based polyanion particles (E) complexed with the sodium composite oxide on the surface and internal voids of the sodium composite oxide secondary particles (D) are represented by the following formula (VII):
Na _w Cog _′ Ni _{h ′} M ⁹ _{i ′} PO ₄ (VII)
(In the formula (VII), M ⁹ represents Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd or Gd. W, g ′, h ′ and i 'Is 0.8 ≦ w ≦ 1.2, 0 ≦ g ′ ≦ 1.2, 0 ≦ h ′ ≦ 1.2, 0 ≦ i ′ ≦ 0.3, g ′ + h ′ ≠ 0, and 0. 8 ≦ (g ′ + h ′ + i ′) ≦ 1.2 and w + 2g ′ + 2h ′ + (valence of M ⁹ ) × i ′ = 3 is shown.)
Or the following formula (VIII):
Na _x Co _{j ′} Ni _{k ′} M ¹⁰ _{l ′} SiO ₄ (VIII)
(.X shown in the formula ^{(VIII), M 10} is Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, and Nd or Gd, j ', k', and l Is 1.6 ≦ x ≦ 2.4, 0 ≦ j ′ ≦ 1.2, 0 ≦ k ′ ≦ 1.2, 0 ≦ l ′ ≦ 1.2, j ′ + k ′ ≠ 0, and 0. 8 ≦ (j ′ + k ′ + l ′) ≦ 1.2 is satisfied and x + 2j ′ + 2k ′ + (valence of M ¹⁰ ) × l ′ = 4 is indicated.)
And a compound containing at least either cobalt or nickel and capable of providing good sodium ion conductivity. The sodium ion conductivity of the sodium-based polyanion particles (E) is preferably 1 × 10 ⁻⁷ S / cm or more, and more preferably 1 × 10 ⁻⁶ S / cm or more.
The sodium-based polyanion particles (E) may be combined with primary particles that are sodium composite oxide particles, and are secondary particles (D) that are formed by aggregation of primary particles that are sodium composite oxide particles. It may be combined directly with the part.

Specific examples of the sodium-based polyanion particles (E) represented by the above formula (VII) include LiCoPO ₄ , NaCo _0.75 Ni _0.25 PO ₄ , NaCo _0.7 Ni _0.2 Mn _0.1 PO ₄ , and NaCo _0.7 Ni _0.2 Fe _0.1. PO ₄ , Na _0.9 Co _1.05 PO ₄ , Na _1.1 Co _0.95 PO ₄ , Na _1.1 Co _0.75 Ni _0.20 PO _{4 and the} like. Among these, NaCoPO ₄ or NaCo _0.7 Ni _0.2 Mn _0.1 PO ₄ is preferable.
Furthermore, specific examples of the sodium-based polyanion particles (E) represented by the above formula (VIII) include, for example, Na ₂ CoSiO ₄ , Na ₂ Co _0.5 Ni _0.5 SiO ₄ , Na ₂ Co _0.4 Ni _0.4 Mn _0.2 SiO ₄ , Na ₂ Co _0.4 Ni _0.4 Fe _0.2 SiO ₄ , Li _2.2 Co _0.9 SiO ₄ , Li _1.8 Co _1.1 SiO ₄ , Li _2.2 Co _0.5 Ni _0.4 SiO _{4 and the} like. Among these, Na ₂ CoSiO ₄ or Na ₂ Co _0.4 Ni _0.4 Mn _0.2 SiO ₄ is preferable.

  Further, the sodium-based polyanion particles (E) form a core-shell structure having a core portion (inside) and a shell portion (surface layer portion) composed of sodium-based polyanion particles represented by the above formula (VII) or (VIII). It may be made.

Due to the core-shell structure of the sodium-based polyanion particles (E), a sodium-based polyanion having a high Mn content that is easily eluted from the sodium-based polyanion particles (E) into the electrolyte is disposed in the core, and the shell is in contact with the electrolyte A sodium-based polyanion having a low Mn content or a sodium-based polyanion having a high Co content, which is highly toxic to the human body or the environment, is disposed in the core portion, and the shell portion in contact with the electrolyte has a low Co content. By arranging the sodium-based polyanion or the like, it is possible to further improve the suppression of the deterioration of the cycle characteristics due to the sodium-based polyanion particles and the securing of safety. At this time, the core part may be a single phase or may be composed of two or more phases having different compositions. As an aspect in which the core part is composed of two or more phases, a structure in which a plurality of phases are concentrically stacked and laminated, or a structure in which the composition changes transitionally from the surface of the core part toward the center part may be used. Good.
Furthermore, the shell part should just be formed in the outer side of a core part, may be 1 phase like a core part, and may be comprised by 2 or more phases from which a composition differs.

As sodium-based polyanion particles (E) formed by forming a core-shell structure with two or more kinds of sodium-based polyanion particles having different compositions, specifically, (core portion)-(shell portion) is, for example, (NaCoPO ₄ )-(NaNiPO ₄ ), (NaCo _0.8 Mn _0.2 PO ₄ )-(NaNiPO ₄ ), (NaCoPO ₄ )-(NaFe _0.3 Ni _0.7 PO ₄ ), (Na ₂ CoSiO ₄ )-(Na ₂ NiSiO ₄₎ ), (Na ₂ Co _0.8 Mn _0.2 SiO ₄ ) — (Na ₂ NiSiO ₄ ), (Na ₂ CoSiO ₄ ) — (Na ₂ Fe _0.3 Ni _0.7 SiO ₄ ), or the like.

The shape of the lithium-based polyanion particles (B) represented by the above formula (V) or the above formula (VI) and the sodium-based polyanion particles (E) represented by the above formula (VII) or the above formula (VIII) are particularly Although not limited, the average particle size of the lithium-based polyanion particles (B) and the sodium-based polyanion particles (E) is the surface of the lithium composite oxide secondary particles (A) or the sodium composite oxide secondary particles (D). In addition, in the internal voids, the thickness is preferably 10 nm to 500 nm, more preferably 10 nm to 300 nm, from the viewpoint of intimately complexing with the lithium composite oxide particles or the sodium composite oxide particles.
The average particle size of the lithium-based polyanion particles (B) and sodium-based polyanion particles (E) formed with a core-shell structure is also 10 nm to 500 nm, preferably 10 nm to 300 nm, as described above. .

The mass ratio ((A) :( B)) between the content of the lithium composite oxide secondary particles (A) and the content of the lithium-based polyanion particles (B) is 95: 5 to 50:50. And 90: 10-50: 50 is preferable and 85: 15-50: 50 is more preferable.
The mass ratio ((D) :( E)) between the content of the sodium composite oxide secondary particles (D) and the content of the sodium-based polyanion particles (E) is 95: 5 to 50: 50, preferably 90:10 to 50:50, and more preferably 85:15 to 50:50.

The composite oxide secondary particles (A) or (D) have water-insoluble carbon particles (C) embedded in the internal voids and water-insoluble carbon particles (C) supported on the surface. The content of the composite oxide secondary particles (A) or (D), the lithium-based polyanion particles (B) or the sodium-based polyanion particles (E), and the water-insoluble carbon particles (C). The mass ratio ((A): ((B) + (C)) or (D): ((E) + (C))) to the total content is preferably 95: 5 to 50:50. 90:10 to 50:50 is preferable, and 85:15 to 50:50 is more preferable.
Further, the mass ratio of the lithium-based polyanion particles (B) or sodium-based polyanion particles (E) in the composite oxide secondary particles (A) or (D) to the water-insoluble carbon particles (C) ((B ) :( C) or (E) :( C)) is preferably 95: 5 to 70:30, more preferably 90:10 to 75:25.

  The method for producing a positive electrode active material composite for a lithium ion secondary battery or a method for producing a positive electrode active material composite for a sodium ion secondary battery according to the present invention comprises a lithium composite oxide secondary particle (A) or a sodium composite oxide two. A step of compounding lithium composite oxide particles or sodium composite oxide particles with lithium-based polyanion particles (B) or sodium-based polyanion particles (E) on the surface and internal voids of the secondary particles (D);

Specifically, the method for producing a positive electrode active material composite for a lithium ion secondary battery or the method for producing a positive electrode active material composite for a sodium ion secondary battery includes the following steps (X) to (Z):
(X) A mixed powder containing a lithium compound or a sodium compound, a nickel compound, a cobalt compound, and a manganese compound is fired, and the composite oxide secondary particles (A) or (A) or ( D) or calcining a mixed powder containing a lithium compound or a sodium compound, a nickel compound, a cobalt compound, and an aluminum compound to obtain composite oxide secondary particles of formula (II) or formula (IV) ( Obtaining A) or (D);
(Y) at least one of lithium compound or sodium compound, cobalt compound or nickel compound, and phosphoric acid compound or silicic acid compound, and lithium composite oxide secondary particles (A) obtained in step (X), or sodium The composite oxide secondary particles (D) are subjected to a hydrothermal reaction, so that lithium composite oxide is formed on the surface and internal voids of the lithium composite oxide secondary particles (A) or the sodium composite oxide secondary particles (D). A step of obtaining a lithium-based composite or sodium-based composite in which particles or sodium composite oxide particles and lithium-based polyanion particles (B) or sodium-based polyanion particles (E) are combined; and (Z) step (Y) The step comprises washing and drying the lithium-based composite or sodium-based composite obtained in (1).

  Next, the manufacturing method of the positive electrode active material composite for a lithium ion secondary battery will be described more specifically. In addition, about the manufacturing method of the positive electrode active material composite for sodium ion secondary batteries, what is necessary is just to replace the word "lithium" in the manufacturing method of the positive electrode active material composite for lithium ion secondary batteries with "sodium."

  In step (X), a mixed powder containing a lithium compound, a nickel compound, a cobalt compound, and a manganese compound is fired to obtain the composite oxide secondary particles (A) of the formula (I), or the lithium compound , Firing a mixed powder containing a nickel compound, a cobalt compound, and an aluminum compound to obtain composite oxide secondary particles (A) of the formula (II).

In order to obtain the Li-NCM composite oxide of the formula (I), a raw material compound such as a nickel compound, a cobalt compound, and a manganese compound is dissolved in water so as to have a desired composite oxide composition, and an aqueous solution. Get A. Examples of such nickel compounds, cobalt compounds, and manganese compounds include sulfates, nitrates, carbonates, acetates, oxalates, oxides, hydroxides, and halides of the metal elements. Specific examples include nickel sulfate, cobalt sulfate, manganese sulfate, nickel acetate, cobalt acetate, and manganese acetate, but are not limited thereto.
In this process, if necessary, Mg may be used as a metal element (M ¹ ) for substituting a part of the layered lithium metal composite oxide constituting the active material so as to have a desired composite oxide composition. , Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi and Ge The above elements may be mixed.

  Next, an alkaline solution is added to the aqueous solution A to obtain an aqueous solution B, and the dissolved metal moisture is coprecipitated by a neutralization reaction to obtain a metal composite hydroxide. The alkaline solution is dropped in an amount sufficient to maintain the pH of the aqueous solution B at 10-14. As the alkaline solution, for example, an aqueous solution of sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia or the like can be used, but sodium hydroxide, sodium carbonate or a mixed solution thereof is preferably used.

  The aqueous solution B is stirred to produce a metal composite hydroxide, and the temperature of the aqueous solution B during the reaction is preferably 30 ° C. or higher, more preferably 30 ° C. to 60 ° C. Further, the stirring time of the aqueous solution B is preferably 30 minutes to 120 minutes, and more preferably 30 minutes to 60 minutes.

  After stirring, the aqueous solution B is filtered to recover the metal composite hydroxide. The recovered metal composite hydroxide is preferably washed with water and then dried.

  Next, the metal composite hydroxide and the lithium compound are dry-mixed so as to have a desired composite oxide composition, and calcined in an oxygen atmosphere, whereby the Li-NCM composite oxide of the formula (I) is obtained. Can be obtained. As the lithium compound, for example, lithium hydroxide or a hydrate thereof, lithium peroxide, lithium nitrate, lithium carbonate and the like can be preferably used. For the dry mixing of the metal composite hydroxide and the lithium compound, a normal dry mixer or a mixing granulator such as a ball mill or a V blender can be used, and it is more preferable to use a planetary ball mill capable of revolving.

  The firing of the mixture of the metal composite hydroxide and the lithium compound is preferably performed in two stages (temporary firing and main firing). By removing the thermal decomposition components such as water molecules and carbon dioxide from the hydroxide and carbonate in the above mixture by pre-baking and then performing main baking, the Li-NCM complex oxidation of formula (I) is efficiently performed. You can get things. The pre-baking conditions are not particularly limited, but the rate of temperature rise is preferably from room temperature to 1 ° C./min to 20 ° C./min. The atmosphere is preferably an air atmosphere or an oxygen atmosphere. Moreover, it is preferable that it is 400 to 1000 degreeC, and, as for baking temperature, it is more preferable that it is 450 to 750 degreeC. Furthermore, the firing time is preferably 1 hour to 20 hours, and more preferably 1 hour to 10 hours.

The conditions for the next main baking are not particularly limited, but the temporary baking after calcination and then crushed with a mortar or the like is performed again from room temperature to a heating rate of 1 ° C./min to 20 ° C. / Min. The atmosphere at this time is preferably in air or in an oxygen atmosphere. Moreover, it is preferable that it is 600 to 1200 degreeC, and, as for baking temperature, it is more preferable that it is 650 to 900 degreeC. Furthermore, the firing time is preferably 3 hours to 30 hours, and more preferably 5 hours to 25 hours.
For this two-stage firing, an electric furnace, a rotary kiln, a tubular furnace, a pusher furnace, etc. adjusted to a gas atmosphere with an oxygen concentration of 20% by mass or more such as an oxygen atmosphere, a dehumidified and decarboxylated dry air atmosphere, etc. are used. be able to.

  The average particle diameter of the primary particles of the Li—NCM composite oxide can be controlled by adjusting the firing temperature of the main firing. In order to set the average particle size of the primary particles of the Li—NCM composite oxide of the above formula (I) to 50 nm to 500 nm, the firing temperature is preferably 700 ° C. to 1000 ° C., more preferably 750 ° C. to 900 ° C. That's fine.

  Furthermore, the internal porosity of the composite oxide secondary particles can be controlled by adjusting the firing time of the main firing. In order to set the internal porosity of the composite oxide secondary particles (A) composed of primary particles that are Li-NCM composite oxide particles of the above formula (I) to 4 vol% to 12 vol%, the firing time is preferably May be 6 hours to 12 hours, more preferably 8 hours to 10 hours.

  Finally, the obtained fired product is washed with water, filtered and dried to obtain composite oxide secondary particles (A) of the formula (I). Here, the drying is performed in two stages, and the moisture in the secondary particles of the Li-NCM composite oxide (water content measured at a vaporization temperature of 300 ° C.) is 1% by mass or less. It is preferable to dry at 90 ° C. or lower until the second stage of drying at 120 ° C. or higher. The moisture content may be measured using, for example, a Karl Fischer moisture meter.

  When producing a Li-NCM complex oxide having a core-shell structure, the complex oxide secondary particles obtained by the main calcination in the step (X) are used as a core portion, and the complex oxide constituting the core portion What is necessary is just to repeat process (X) so that the Li-NCM type complex oxide from which a composition differs may be produced | generated on the surface of a secondary particle. The process for generating this shell part is referred to as process (x).

  In the step (x), in order to obtain the Li-NCM composite oxide serving as the shell portion, the composition of the desired Li-NCM composite oxide is obtained in the same manner as in the method for producing the aqueous solution A in the step (X). After obtaining the corresponding aqueous solution a, an aqueous solution b containing a metal composite hydroxide is obtained in the same manner as in the method for producing the aqueous solution B in the step (X).

  Next, the composite oxide secondary particles constituting the core part obtained by the main calcination in the step (X) are mixed and stirred into the aqueous solution b, and the temperature is raised from room temperature to 1 ° C./min to 20 ° C./min. Heat to 100 ° C. to 110 ° C. at a speed, and stir while heating in the heating temperature range in air or oxygen atmosphere to evaporate water by 90% or more. Thereby, the raw material of the Li-NCM system complex oxide particle which comprises a shell part can be co-precipitated on the surface of the complex oxide secondary particle which comprises a core part. In addition, the thickness of a shell part is controllable by adjusting heating temperature.

  The particles obtained through the above steps are subjected to two-step firing and two-step drying in the same manner as in step (X), then washed with water, then filtered, and dried to obtain lithium having a core-shell structure. Composite oxide secondary particles (A) are obtained.

Next, in the step (X), the case where the composite oxide secondary particles (A) of the formula (II) are obtained will be specifically described.
In order to obtain the composite oxide secondary particles (A) of the formula (II), a raw material compound such as a nickel compound, a cobalt compound, and an aluminum compound is dissolved in water so as to have a desired composite oxide composition. To obtain an aqueous solution A ′. Examples of such nickel compounds, cobalt compounds, and aluminum compounds include sulfates, nitrates, carbonates, acetates, oxalates, oxides, hydroxides, and halides of the metal elements. Specific examples include, but are not limited to, nickel sulfate, cobalt sulfate, aluminum sulfate, nickel acetate, cobalt acetate, and aluminum acetate. In this process, if necessary, Mg may be used as a metal element (M ₂ ) for substituting a part of the layered lithium metal composite oxide constituting the active material so as to have a desired composite oxide composition. , Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi, and Ge Elements may be mixed.

  Next, an alkaline agent is added to the aqueous solution A ′ to obtain an aqueous solution B ′, and the dissolved metal water is coprecipitated by a neutralization reaction to obtain a metal composite hydroxide. The alkaline agent is dropped in an amount sufficient to maintain the pH of the aqueous solution B ′ at 10-14. As the alkaline agent, for example, an aqueous solution of sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia or the like can be used, but it is preferable to use ammonia, sodium hydroxide, sodium carbonate or a mixed solution thereof.

  The aqueous solution B ′ is stirred to produce a metal composite hydroxide. The temperature of the aqueous solution B ′ during this reaction is preferably 40 ° C. or higher, more preferably 40 ° C. to 60 ° C. Further, the stirring time of the aqueous solution B ′ is preferably 30 minutes to 120 minutes, and more preferably 30 minutes to 60 minutes.

  In order to obtain a metal composite hydroxide having a high bulk density, an oxidizing agent such as sodium hypochlorite or hydrogen peroxide may be further added to the aqueous solution B ′ after the reaction.

After stirring, the aqueous solution B ′ is filtered to recover the metal composite hydroxide. The recovered metal composite hydroxide is preferably fired to form a metal composite oxide. By reacting with the lithium compound as the metal composite oxide, the quality of the obtained Li-NCA composite oxide can be stabilized and can be uniformly and sufficiently reacted with lithium.
The firing conditions for obtaining the metal composite oxide are not particularly limited. For example, the firing may be performed in an air atmosphere at a temperature of preferably 500 ° C to 1100 ° C, more preferably 600 ° C to 900 ° C.

  Next, the above-mentioned metal composite oxide and lithium compound are dry-mixed so as to have a desired composite oxide composition, and fired in an oxygen atmosphere to obtain a Li-NCA composite oxide of formula (II). be able to. The lithium compound is not particularly limited, and for example, lithium hydroxide or a hydrate thereof, lithium peroxide, lithium nitrate, lithium carbonate and the like can be preferably used. For the dry mixing of the metal composite oxide and the lithium compound, an ordinary dry mixer or a mixing granulator such as a ball mill or a V blender can be used. For firing, an oxygen atmosphere, dehumidification and decarboxylation are performed. An electric furnace, a rotary kiln, a tubular furnace, a pusher furnace, or the like adjusted to a gas atmosphere having an oxygen concentration of 20% by mass or more such as a dry air atmosphere can be used.

In the firing of the mixture of the metal composite oxide and the lithium compound, the firing temperature is preferably 650 ° C to 850 ° C, and more preferably 700 ° C to 800 ° C. At a firing temperature of less than 650 ° C., the resulting Li—NCA composite oxide crystals are undeveloped and structurally unstable, and the structure is easily destroyed by charge and discharge. On the other hand, when the firing temperature exceeds 850 ° C., the layered structure of the Li—NCA-based composite oxide collapses, making it difficult to insert and desorb lithium ions. The firing time is preferably 5 hours to 20 hours, and more preferably 6 hours to 10 hours.
Furthermore, in order to remove the crystal water or carbonic acid of the lithium compound, it is preferable to perform two-stage firing in the same manner as the NCM-based composite oxide. What is necessary is just to carry out for 1 hour or more, and to perform 2nd stage main baking at 650 to 850 ° C. for 5 hours or more.

Finally, the obtained fired product is washed with water, filtered and dried to obtain composite oxide secondary particles (A) of the formula (II). The slurry concentration when washing the fired product with water is preferably 200 g / L to 4000 g / L, and more preferably 500 g / L to 2000 g / L. If the slurry concentration is less than 200 g / L, lithium may be desorbed from the secondary particles of the Li-NCA composite oxide.
In addition, when the water used for washing contains a large amount of carbon dioxide, lithium carbonate is precipitated in the composite oxide secondary particles (A) of the formula (II). Less than 10 μS / cm is preferable, and water of 1 μS / cm or less is more preferable.

  In the production method of the present invention, in this step (X), the drying performed after washing with water and filtration needs to be performed in two stages. The first stage drying is performed at 90 ° C. or less until the moisture in the secondary particles (moisture ratio measured at a vaporization temperature of 300 ° C.) is 1% by mass or less, and then the second stage drying is performed at 120 ° C. This is done.

In the step (Y), at least one of a lithium compound, a cobalt compound or a nickel compound, a phosphoric acid compound or a silicic acid compound, and the lithium composite oxide secondary particles (A) obtained in the step (X) are hydrothermally heated. Subject to reaction
This is a step of obtaining a lithium-based composite in which lithium composite oxide particles and lithium-based polyanion particles (B) are combined on the surface and internal voids of the lithium composite oxide secondary particles (A).

  In the step (Y), a phosphoric acid compound or a silicic acid compound is added to the slurry a1 containing a lithium compound, and then a metal salt containing at least a cobalt compound or a nickel compound, and lithium composite oxide secondary particles (A) are added. Then, after obtaining slurry a2, slurry a2 is subjected to a hydration reaction.

  The content of the lithium compound in the slurry a2 is preferably 5 to 50 parts by mass, more preferably 7 to 45 parts by mass with respect to 100 parts by mass of water. More specifically, when a phosphoric acid compound is used, the content of the lithium compound in the slurry a2 is preferably 5 parts by mass to 50 parts by mass, more preferably 10 parts by mass to 100 parts by mass of water. 45 parts by mass. Moreover, when a silicic acid compound is used, content of the lithium compound in the slurry a2 is preferably 5 to 40 parts by mass, more preferably 7 to 35 parts by mass with respect to 100 parts by mass of water. is there.

  Before adding a phosphoric acid compound or a silicic acid compound to the slurry a1, it is preferable to stir the slurry a1 in advance. The stirring time of the slurry a1 is preferably 1 minute to 15 minutes, more preferably 3 minutes to 10 minutes. Moreover, the temperature of slurry a1 becomes like this. Preferably it is 20 to 90 degreeC, More preferably, it is 20 to 70 degreeC.

When using phosphoric acid which is an aqueous solution as the phosphoric acid compound, when adding phosphoric acid to the slurry a1, it is preferable to add phosphoric acid dropwise while stirring the slurry a1. By adding phosphoric acid dropwise to the slurry a1 and adding small amounts little by little, the reaction proceeds well in the slurry a1, and Li ₃ PO ₄ is produced while being uniformly dispersed in the slurry a1.

  The dropping rate of phosphoric acid into the slurry a1 is preferably 15 mL / min to 50 mL / min, more preferably 20 mL / min to 45 mL / min, and further preferably 28 mL / min to 40 mL / min. Moreover, the stirring time of the slurry a1 while dropping phosphoric acid is preferably 0.5 hours to 24 hours, and more preferably 3 hours to 12 hours. Furthermore, the stirring speed of the slurry a1 while dropping phosphoric acid is preferably 200 rpm to 700 rpm, more preferably 250 rpm to 600 rpm, and further preferably 300 rpm to 500 rpm.

  The slurry a1 after the addition of the phosphoric acid compound or the silicic acid compound preferably contains 2.0 mol to 4.0 mol of lithium with respect to 1 mol of phosphoric acid or silicic acid, and 2.0 mol to 3. mol. It is more preferable to contain 1 mol, and the lithium compound and the phosphoric acid compound or the silicic acid compound may be used so as to obtain such an amount. More specifically, when a phosphoric acid compound is used, the slurry a1 after the addition of the phosphoric acid compound preferably contains 2.7 mol to 3.3 mol of lithium with respect to 1 mol of phosphoric acid, It is more preferable to contain 2.8 mol-3.1 mol, and when a silicic acid compound is used, the slurry a1 after adding a silicic acid compound is 2.0 mol-lithium with respect to 1 mol of silicic acid. It is preferable to contain 4.0 mol, and it is more preferable to contain 2.0 mol-3.0 mol.

By purging nitrogen to the slurry a1 after the addition of the phosphoric acid compound or the silicate compound, the reaction in the slurry a1 is completed to obtain Li ₃ PO ₄ or a silicate precursor as a slurry. . When nitrogen is purged, the reaction can proceed in a state where the dissolved oxygen concentration in the slurry a1 is reduced, and the dissolved oxygen concentration of the resulting slurry containing Li ₃ PO ₄ or silicate precursor is also Since it is effectively reduced, oxidation of the metal salt to be added next can be suppressed. In slurries containing such Li ₃ PO ₄ or silicate precursors, they exist as finely dispersed particles.

The pressure when purging nitrogen is preferably 0.1 MPa to 0.2 MPa, more preferably 0.1 MPa to 0.15 MPa. Moreover, the temperature of the slurry a1 after adding a phosphoric acid compound or a silicic acid compound becomes like this. Preferably it is 20 to 80 degreeC, More preferably, it is 20 to 60 degreeC. The reaction time is preferably 5 minutes to 60 minutes, more preferably 15 minutes to 45 minutes.
Furthermore, when purging nitrogen, it is preferable to stir slurry a1 after adding a phosphoric acid compound or a silicic acid compound from a viewpoint of making reaction progress favorable. The stirring speed at this time is preferably 200 rpm to 700 rpm, more preferably 250 rpm to 600 rpm.

Further, from the viewpoint of more effectively miniaturizing Li ₃ PO ₄ or a silicate precursor, the dissolved oxygen concentration in the slurry a1 after adding the phosphoric acid compound or the silicate compound is 0.5 mg / L or less. And is more preferably 0.2 mg / L or less.

Next, a slurry a2 is obtained by adding a metal salt containing at least a cobalt compound or a nickel compound and lithium composite oxide secondary particles (A) to the slurry a1. The total addition amount of the metal salt containing at least a cobalt compound or a nickel compound is preferably 0.99 mol to 1.01 mol with respect to 1 mol of phosphate ions or silicate ions contained in the slurry a2. Preferably it is 0.995 mol-1.005 mol. In the case of using a cobalt or nickel other metals (M ⁵ or M ⁶⁾ salt, cobalt compounds, nickel compounds, and metal total amount of (M ⁵ or M ⁶⁾ salt, phosphorus in the slurry a2 obtained Preferably it is 0.99 mol-1.01 mol with respect to 1 mol of acid or silicic acid, More preferably, it is 0.995 mol-1.005 mol.
Incidentally, the cobalt compound, nickel compound, order of addition of the metal (M ⁵ or M ⁶⁾ salt and lithium composite oxide secondary particle (A) is not particularly limited. Moreover, when adding these metal salts, you may add antioxidant as needed. As such an antioxidant, sodium sulfite (Na ₂ SO ₃ ), sodium hydrosulfite (Na ₂ S ₂ O ₄ ), aqueous ammonia and the like can be used. The addition amount of the antioxidant is a cobalt compound, a nickel compound, a metal (M ⁵ or M ⁶ ) salt from the viewpoint of preventing generation of the lithium-based polyanion particles (C) due to excessive addition. The total amount is preferably 0.01 mol to 1 mol, more preferably 0.03 mol to 0.5 mol.

  The addition amount of the lithium composite oxide secondary particles (A) is preferably 60 parts by mass to 800 parts by mass with respect to 100 parts by mass of the metal salt containing at least the cobalt compound or the nickel compound added to the slurry a2. More preferably, it is 70 mass parts-650 mass parts.

  Next, in the step (Y), the obtained slurry a2 is subjected to a hydrothermal reaction, and lithium composite oxide particles and lithium-based polyanion particles (on the surface and internal voids of the lithium composite oxide secondary particles (A)) ( This is a step of obtaining a lithium-based composite (A) in which B) is combined. Since the slurry a2 obtained in the above process is used as it is as the precursor of the lithium-based polyanion particle (B), the process can be simplified, and it is extremely fine and very useful as a positive electrode material. A lithium-based composite obtained by combining the polyanion positive electrode active material useful for the surface of the lithium composite oxide secondary particles (A) and the internal voids can be obtained.

  The amount of water used for the hydrothermal reaction is selected from lithium composite oxide secondary particles contained in the slurry a2 from the viewpoint of the solubility of the metal salt, the ease of stirring, the efficiency of synthesis, and the like ( A) Preferably, it is 10-100 mass parts with respect to 1 mass part, More preferably, it is 20-50 mass parts.

  The temperature for the hydrothermal reaction may be 100 ° C. or higher, and preferably 130 ° C. to 180 ° C. The hydrothermal reaction is preferably performed in a pressure vessel. When the reaction is performed at 130 ° C to 180 ° C, the pressure at this time is preferably 0.3 MPa to 0.9 MPa, and the reaction is performed at 140 ° C to 160 ° C. The pressure in carrying out is preferably 0.3 MPa to 0.6 MPa. The hydrothermal reaction time is preferably 0.1 to 48 hours, more preferably 0.2 to 24 hours.

When producing lithium-based polyanion particles (B) formed with a core-shell structure, the lithium-based polyanion particles obtained in the above step (Y) are used as a core portion, and the lithium-based polyanion particles constituting the core portion After mixing the lithium-based polyanion particles obtained in the above step with the slurry a2 prepared so that the lithium-based polyanion composition b is generated on the surface so as to generate the lithium-based polyanion composition b having a different composition. The hydrothermal reaction may be performed in the same manner as described above.
By repeating this step, lithium-based polyanion particles (B) having a concentric layer structure composed of two or more layers of different lithium-based polyanion compositions can be obtained.

  At this time, the particle size of the lithium-based polyanion particles as the core can be controlled by adjusting the temperature, pressure, and time of the hydrothermal reaction when the lithium-based polyanion particles are produced, and the shell becomes a shell. The coating thickness of the lithium-based polyanion composition b can be controlled by adjusting the temperature, pressure and time of the hydrothermal reaction when the lithium-based polyanion composition b is produced.

  Raw material compound for producing lithium-based polyanion composition b in slurry a2 in the production of lithium-based polyanion particles (B) formed with the core-shell structure, when the number of repetitions is the second or later The content of is preferably 0.5% by mass to 10% by mass in 100% by mass of the slurry a2 from the viewpoint of uniformly forming a coating layer of the lithium-based polyanion composition b.

Step (Z) is a step of washing and drying the lithium composite obtained in step (Y).
In the step (Y), the slurry obtained after the hydrothermal reaction is subjected to solid-liquid separation, and the target lithium-based composite is obtained as a solid content. Examples of the apparatus used for solid-liquid separation include a filter press machine and a centrifugal filter machine. Especially, it is preferable to use a filter press from a viewpoint of obtaining solid content efficiently.

  Next, the recovered lithium-based composite is washed with 10 to 60 parts by mass of washing water with respect to 1 part by mass of the dry mass of the lithium-based composite. Thereby, impurities, such as an anion component, can be removed effectively. The amount of washing water is 10 parts by mass to 60 parts by mass, and preferably 10 parts by mass to 40 parts by mass with respect to 1 part by mass of the dry mass of the lithium composite. Further, the temperature of the washing water is preferably 10 ° C. to 80 ° C., more preferably 10 ° C. to 70 ° C., from the viewpoint of effectively removing impurities.

  The washed lithium-based composite is isolated by drying and becomes a positive electrode active material composite for a lithium ion secondary battery. As the drying means, freeze drying or vacuum drying is used.

The extent to which the lithium-based polyanion particles (B) are combined with the lithium composite oxide particles on the surface of the lithium composite oxide secondary particles (A) and coat the surfaces is determined by X-ray photoelectron spectroscopy (XPS). ). Specifically, when the obtained positive electrode active material composite for a lithium ion secondary battery is irradiated with several keV of soft X-rays, it is inherent to the element constituting the portion from the portion irradiated with the soft X-ray. Since the photoelectrons having the energy values of 2 are emitted, the peak intensity corresponding to the trivalent Ni obtained by analyzing the peak of Ni2p _3/2 emitted from the lithium composite oxide secondary particles (A), and the lithium system By comparing the peak intensities of P2p or Si2p released from the polyanion particles (B), the area ratio of the portion where the surface of the positive electrode active material composite for a lithium ion secondary battery is exposed, that is, such a lithium-based polyanion It can be seen that the particles (B) cover the lithium composite oxide secondary particles (A). This peak intensity ratio (Ni2p _3/2 trivalent Ni peak intensity) / (P2p peak intensity) or (Ni2p _1/2 peak intensity) / (Si2p peak intensity) is preferably 0.1. Or less, more preferably 0.05 or less. With such a peak intensity ratio, the surface of the obtained positive electrode active material composite for a lithium ion secondary battery is densely covered with the lithium-based polyanion particles (B).

  Furthermore, lithium-based polyanion particles complexed with lithium composite oxide particles in the surface and internal voids of the lithium composite oxide secondary particles (A) by a transmission electron microscope (TEM-EDX) in which element distribution can be confirmed (B) can be observed directly. Specifically, the positive electrode active material composite for a lithium ion secondary battery is observed by observing an electron image and a P or Si distribution image on the fracture surface or polished surface of the positive electrode active material composite for a lithium ion secondary battery. The composite part of lithium composite oxide particles and lithium-based polyanion particles (B) can be confirmed.

Further, the water-insoluble carbon particles (C) are embedded in the internal voids of the NCM-based secondary particles (A) or (D) or the NCA-based composite oxide secondary particles (A) or (D), A method for producing a positive electrode active material composite for a lithium ion secondary battery supported on a surface or a method for producing a positive electrode active material composite for a sodium ion secondary battery further uses water-insoluble carbon particles (C), and a lithium composite It is preferable to include a step of supporting the water-insoluble carbon particles (C) on the surfaces of the oxide secondary particles (A) or the sodium composite oxide secondary particles (D). Specifically, the method for producing a positive electrode active material composite for a lithium ion secondary battery or the method for producing a positive electrode active material composite for a sodium ion secondary battery is specifically described in the following steps (X ′) to (Z ′). ):
(X ′) calcining a mixed powder containing a lithium compound or sodium compound, a nickel compound, a cobalt compound, and a manganese compound to obtain an NCM-based composite oxide of formula (I) or formula (III), or Firing a mixed powder containing a lithium compound or sodium compound, a nickel compound, a cobalt compound, and an aluminum compound to obtain an NCA-based composite oxide of formula (II) or formula (IV);
(Y ′) Water-insoluble carbon particles (C), at least one of lithium compound or sodium compound, cobalt compound or nickel compound, and phosphoric acid compound or silicic acid compound, and lithium composite oxidation obtained in step (I ′) The product secondary particles (A) or the sodium composite oxide secondary particles (D) are subjected to a hydrothermal reaction,
Lithium composite oxide particles and lithium-based polyanion particles (B) are combined on the surface and internal voids of the lithium composite oxide secondary particles (A), and the internal voids of the lithium composite oxide secondary particles (A) A lithium-based composite in which water-insoluble carbon particles (C) are embedded, and in addition, water-insoluble carbon particles (C) are supported on the surfaces of secondary particles (A) of the lithium composite oxide, or sodium composite oxide Sodium composite oxide particles and sodium-based polyanion particles (E) are complexed on the surface and internal voids of the secondary particles (D), and water-insoluble carbon is further incorporated in the internal voids of the sodium complex oxide secondary particles (D). Obtaining a sodium-based composite in which the particles (C) are embedded and in addition the water-insoluble carbon particles (C) are supported on the surfaces of the sodium composite oxide secondary particles (D); and
(Z ′) comprising a step of washing and drying the lithium-based composite or sodium-based composite obtained in the step (Y ′).

Next, the manufacturing method of the positive electrode active material composite for lithium ion secondary batteries using water-insoluble carbon particles (C) will be described more specifically. In addition, about the manufacturing method of the positive electrode active material composite for sodium ion secondary batteries, what is necessary is just to replace the word "lithium" in the manufacturing method of the positive electrode active material composite for lithium ion secondary batteries with "sodium."
In the method for producing a positive electrode active material composite for a lithium ion secondary battery using water-insoluble carbon particles (C), the step (X ′) is the same as the step (X). explain.

  In the step (Y ′), at least one of the lithium composite oxide secondary particles (A) obtained in the step (X ′) and the lithium compound, cobalt compound, or nickel compound that is a raw material of the lithium-based polyanion particles (B). One and a slurry in which a phosphoric acid compound or a silicic acid compound and water-insoluble carbon particles (C) are mixed are subjected to a hydrothermal reaction, and on the surface and internal voids of the lithium composite oxide secondary particles (A), Lithium composite oxide particles and lithium-based polyanion particles (B) are complexed, and water-insoluble carbon particles (C) are embedded in the internal voids of the lithium composite oxide secondary particles (A). This is a step of obtaining a lithium-based composite (B) in which water-insoluble carbon particles (C) are supported on the surface of the composite oxide secondary particles (A).

  Step (Y ′) is a step of subjecting a predetermined raw material compound to a hydrothermal reaction in the same manner as in the production method used in step (Y). That is, in the step (Y ′), the composite oxide secondary particles (A) composed of at least one or more of the Li—NCM composite oxide or the Li—NCA composite oxide obtained in the step (X ′). ), A metal salt containing at least one of a lithium compound, a cobalt compound or a nickel compound which is a raw material of the lithium-based polyanion particles (B), a phosphoric acid compound or a silicic acid compound, and water-insoluble carbon particles (C) The lithium-based composite is obtained through a thermal reaction.

Moreover, the handling of the water-insoluble carbon particles (C) in the step (Y ′) may be the same as the lithium composite oxide secondary particles (A) in the step (Y).
That is, in the step (Y ′), a phosphoric acid compound or a silicic acid compound is added to the slurry a1 ′ containing a lithium compound, and then a metal salt containing at least a cobalt compound or a nickel compound, and lithium composite oxide secondary particles ( In this step, slurry A2 ′ is obtained by adding A) and water-insoluble carbon particles (C), and then subjecting slurry a2 ′ to a hydration reaction.

  Furthermore, in the step (Y ′), the mass ratio of the content of the lithium composite oxide secondary particles (A) and the total content of the lithium-based polyanion particles (B) and the water-insoluble carbon particles (C) ( (A): ((B) + (C))) is the amount of the lithium composite oxide secondary particles (A) used, and the raw material of the lithium-based polyanion particles (B) so as to satisfy the above quantitative relationship. The addition amount of the metal salt containing a phosphoric acid compound or a silicic acid compound, at least a cobalt compound or a nickel compound, and the addition amount of the water-insoluble carbon particles (C) are adjusted.

  Here, the molar ratio between the amount of the phosphoric acid compound or silicic acid compound used as the raw material of the lithium-based polyanion particles (B) and the amount of the metal salt containing at least a cobalt compound or a nickel compound is the same as the above step (Y). The same. That is, 2.7 mol to 3.3 mol of lithium for 1 mol of phosphoric acid, and 2.0 mol to 4.0 mol of lithium for 1 mol of silicic acid, phosphate ion or silicate ion 1 The total addition amount of the metal salt is 0.99 mol to 1.01 mol with respect to mol.

  The step (Z ′) is a step of washing the lithium composite obtained in the step (Y ′) and drying to obtain a positive electrode active material composite for a lithium ion secondary battery. In the step (Z), This is the same as the manufacturing method used. That is, after the slurry obtained after the hydrothermal reaction in the above step (Y ′) is subjected to solid-liquid separation to obtain a lithium-based composite, 10 parts by weight with respect to 1 part by mass of the dry weight of the lithium-based composite. What is necessary is just to wash | clean with the mass water-60 mass parts wash water, and to dry.

In the obtained positive electrode active material composite for a lithium ion secondary battery, the lithium-based polyanion particles (B) are combined with the lithium composite oxide particles on the surface of the lithium composite oxide secondary particles (A), and the surface The extent to which water-insoluble carbon particles (C) are supported can be evaluated by X-ray photoelectron spectroscopy (XPS). Specifically, the peak intensity corresponding to trivalent Ni obtained by analyzing the peak of Ni2p _3/2 released from the lithium composite oxide secondary particles (A), and the lithium-based polyanion particles (B). By comparing the sum of the peak intensity of P2p or Si2p released and the peak intensity of P2p or Si2p released from water-insoluble carbon particles (C) and C1s, the positive electrode active material composite for the lithium ion secondary battery It can be seen that the area ratio of the exposed portions of the surface, that is, the extent to which the lithium-based polyanion particles (B) or water-insoluble carbon particles (C) cover the lithium composite oxide secondary particles (A). This peak intensity ratio (Ni2p _3/2 trivalent Ni peak intensity) / ((P2p peak intensity) + (C1s peak intensity)) or (Ni2p _3/2 trivalent Ni peak intensity) / ((Peak intensity of Si2p) + (peak intensity of C1s)) is preferably 0.1 or less, more preferably 0.05 or less. With such a peak intensity ratio, the surface of the obtained positive electrode active material composite for a lithium ion secondary battery is densely covered with lithium-based polyanion particles (B) and water-insoluble carbon particles (C).

  The positive electrode active material composite for a secondary battery of the present invention is applied as a positive electrode material, and a secondary battery that is a lithium ion secondary battery or a sodium ion secondary battery containing the composite includes a positive electrode, a negative electrode, an electrolyte, and a separator. There is no particular limitation as long as it is an essential configuration.

  Here, as for the negative electrode, as long as lithium ions or sodium ions can be occluded at the time of charging and can be released at the time of discharging, the material configuration is not particularly limited, and those having a known material configuration can be used. . For example, a carbon material such as lithium metal, sodium metal, graphite, or amorphous carbon. It is preferable to use an electrode formed of an intercalating material capable of electrochemically inserting and extracting lithium ions or sodium ions, particularly a carbon material.

  The electrolytic solution is obtained by dissolving a supporting salt in an organic solvent. The organic solvent is not particularly limited as long as it is an organic solvent that is usually used for an electrolyte solution of a lithium ion secondary battery or a sodium ion secondary battery. For example, carbonates, halogenated hydrocarbons, ethers, ketones Nitriles, lactones, oxolane compounds and the like can be used.

The type of the supporting salt is not particularly limited, but in the case of a lithium ion secondary battery, an inorganic salt selected from LiPF ₆ , LiBF ₄ , LiClO ₄ and LiAsF ₆ , a derivative of the inorganic salt, LiSO ₃ CF ₃ , an organic material selected from LiC (SO ₃ CF ₃ ) ₂ and LiN (SO ₃ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ and LiN (SO ₂ CF ₃ ) (SO ₂ C ₄ F ₉ ) It is preferably at least one of a salt and a derivative of the organic salt. In the case of a sodium ion secondary battery, an inorganic salt selected from NaPF ₆ , NaBF ₄ , NaClO ₄ and NaAsF ₆ , a derivative of the inorganic salt, NaSO ₃ CF ₃ , NaC (SO ₃ CF ₃ ) ₂ and NaN (SO ₃ CF ₃ ) ₂ , NaN (SO ₂ C ₂ F ₅ ) ₂ and NaN (SO ₂ CF ₃ ) (SO ₂ C ₄ F ₉ ), and at least one of derivatives of the organic salt It is preferable.

  The separator plays a role of electrically insulating the positive electrode and the negative electrode and holding the electrolytic solution. For example, a porous synthetic resin film, particularly a polyolefin polymer (polyethylene, polypropylene) porous film may be used.

  The shape of the lithium ion secondary battery or sodium ion secondary battery having the above configuration is not particularly limited, and various shapes such as a coin shape, a cylindrical shape, and a square shape, and an indeterminate sealed in a laminate outer package. It may be a shape.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.

[Production Example 1: Production of Li-NCM complex oxide particles having no concentration gradient]
After mixing 263 g of nickel sulfate hexahydrate, 281 g of cobalt sulfate heptahydrate, 241 g of manganese sulfate pentahydrate, and 3 L of water so that the molar ratio of Ni: Co: Mn is 1: 1: 1 Then, 25% aqueous ammonia was added dropwise to the mixture at a dropping rate of 300 mL / min to obtain a slurry A1 containing a metal composite hydroxide having a pH of 11.
Next, the slurry A1 was filtered and dried to obtain a metal composite hydroxide mixture B1, and then 37 g of lithium carbonate was mixed with the mixture B1 by a ball mill to obtain a powder mixture C1.
The obtained powder mixture C1 was calcined by calcination at 800 ° C. for 5 hours in an air atmosphere, and then baked at 800 ° C. for 10 hours in an air atmosphere as main calcination. Secondary particles of _0.33 Co _0.33 Mn _0.34 O ₂ ) were obtained. (Average particle size of secondary particles: 10 μm)
Hereinafter, the composite oxide particles are referred to as Li-NCM-1.

[Production Example 2: Production of Li-NCM composite oxide particles having a concentration gradient]
334 g of nickel sulfate hexahydrate, 159 g of cobalt sulfate heptahydrate, 136 g of manganese sulfate pentahydrate, such that the molar ratio of Ni: Co: Mn is 0.53: 0.735: 0.735, and 2.4 L of water was mixed to obtain a Ni-poor aqueous solution A2. Further, 142 g of nickel sulfate hexahydrate, 9 g of cobalt sulfate heptahydrate, and 7 g of manganese sulfate pentahydrate so that the molar ratio of Ni: Co: Mn is 0.9: 0.05: 0.05. And 0.6 L of water was mixed and Ni-rich aqueous solution B2 was obtained. While stirring the Ni-rich aqueous solution B2 with a pump, 25% aqueous ammonia was added dropwise at a dropping rate of 300 mL / min to obtain a slurry C2 containing a metal composite hydroxide having a pH of 11. While stirring the resulting slurry C2, the entire amount of Ni-poor aqueous solution A2 is added, 25% aqueous ammonia is added dropwise to the slurry at a dropping rate of 300 mL / min, and the slurry contains a metal composite hydroxide having a pH of 11 D2 was obtained. Next, the slurry D2 was filtered and dried to obtain a metal composite hydroxide mixture E2, and then 22 g of lithium hydroxide monohydrate was mixed with the mixture E2 by a ball mill to obtain a powder mixture F2. The obtained powder mixture F2 was calcined at 840 ° C. for 10 hours in an air atmosphere, and Ni, Co, and Mn had a concentration gradient (particle center: Ni-rich, Co, Mn-poor) Li-NCM system Secondary particles (average particle size 10 μm) of composite oxide (average composition: LiNi _0.6 Co _0.2 Mn _0.2 O ₂ ) were obtained.
Hereinafter, the composite oxide particle is referred to as Li-NCM-2.

[Production Example 3: Production of Li-NCA composite oxide particles]
370 g of lithium carbonate, 950 g of nickel carbonate, 150 g of cobalt carbonate, 58 g of aluminum carbonate, and 3 L of water were mixed so that the molar ratio of Li: Ni: Co: Al was 1: 0.8: 0.15: 0.05. Then, it was mixed with a ball mill to obtain a powder mixture A3. The obtained powder mixture A3 was calcined by calcination at 800 ° C. for 5 hours in an air atmosphere and then pulverized as main calcination in an air atmosphere at 800 ° C. for 24 hours _. Secondary particles of ₈ Co _0.15 Al _0.05 O ₂ ) were obtained. (Average particle size of secondary particles: 10 μm)
Hereinafter, the composite oxide particles are referred to as Li-NCA.

[Production Example 4: Production of LiCoPO ₄ / C particles]
1272 g of LiOH.H ₂ O and 4 L of water were mixed to obtain slurry A4. While maintaining the slurry A4 at a temperature of 25 ° C. while stirring for 3 minutes, 1153 g of 85% phosphoric acid aqueous solution was dropped at 35 mL / min, followed by cellulose nanofiber (Cerish (registered trademark) KY-100G, manufactured by Daicel Finechem). 707 g of fiber diameter 4 to 100 nm) was added and stirred at a stirring speed of 400 rpm for 12 hours to obtain a slurry B4 containing trilithium phosphate. Next, 2108 g of CoSO ₄ .7H ₂ O was added to the total amount of the obtained slurry B4 to obtain slurry C4.
Subsequently, the obtained slurry C4 was put into an autoclave and subjected to a hydrothermal reaction at 170 ° C. for 1 hour. The pressure in the autoclave was 0.8 MPa. The produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal. The washed crystal was lyophilized at −50 ° C. for 12 hours to obtain a complex D4. 1000 g of the obtained composite D4 was collected, and 1 L of water was added thereto to make a slurry E4. Then, the slurry E4 was subjected to a dispersion treatment with an ultrasonic stirrer (T25, manufactured by IKA) for 1 minute to make the whole uniform Was colored.
Slurry E4 exhibiting uniform coloration was spray-dried using a spray drying apparatus (MDL-050M, manufactured by Fujisaki Electric Co., Ltd.), and then at 700 ° C. for 1 hour in an argon hydrogen atmosphere (hydrogen concentration 3%). Firing was performed to obtain lithium-based polyanion particles LiCoPO ₄ (carbon amount = 1.2% by mass) on which 1.2% by mass of cellulose nanofiber-derived carbon was supported. (Average particle size of primary particles: 100 nm)
Hereinafter, the lithium-based polyanion particles are referred to as LCP / C-1.

[Production Example 5: Production of Li ₂ CoSiO ₄ / C particles]
LiOH _· H 2 _{O 428g,} was obtained _{Na 4 SiO 4 · nH 2 O} 1397g, and water 3.75L by mixing slurry A5. To slurry A5, 1054 g of CoSO ₄ · 7H ₂ O and 784 g of cellulose nanofiber (Cerish (registered trademark) KY-100G) were added and stirred to obtain slurry B5.
Next, the obtained slurry B5 was charged into an autoclave and subjected to a hydrothermal reaction at 150 ° C. for 12 hours. The pressure in the autoclave was 0.4 MPa. The produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal. The washed crystals were lyophilized at −50 ° C. for 12 hours to obtain Complex C5. 500 g of the obtained composite C5 was taken, and 500 mL of water was added thereto to form a slurry D5. Then, the slurry D5 was dispersed with an ultrasonic stirrer (T25) for 1 minute to uniformly color the whole. It was.
2. A slurry D5 exhibiting uniform coloration is subjected to spray drying using a spray drying apparatus (MDL-050M), and then calcined at 650 ° C. for 1 hour in an argon hydrogen atmosphere (hydrogen concentration 3%). Lithium polyanion particles Li ₂ CoSiO ₄ (carbon amount = 3.0% by mass) on which carbon derived from 0% by mass of cellulose nanofibers was supported were obtained. (Average particle size of primary particles: 40 nm)
Hereinafter, the lithium-based polyanion particle is referred to as LCS / C-1.

[Production Example 6: Production of Li _1.2 Co _0.9 PO ₄ / C particles]
519 g of Li ₂ CO _3, 2402 g of (NH ₄ ) ₃ PO ₄ .3H ₂ O, 2644 g of Co (CH ₃ COO) ₂ .4H ₂ O and 4 L of water were mixed with a ball mill to obtain slurry A6. Next, the slurry A6 was filtered and dried to obtain a powder mixture B6. The obtained powder mixture B6 was fired at 700 ° C. for 10 hours in an N ₂ atmosphere. 1000 g of the obtained composite C5 was collected, and 224 g of cellulose nanofiber (Wma-1202, manufactured by Sugino Machine Co., Ltd., fiber diameter: 4 nm to 20 nm) and 1 L of water were added thereto to obtain slurry D6. The obtained slurry D6 was subjected to a dispersion treatment for 1 minute with an ultrasonic stirrer (T25, manufactured by IKA) to uniformly color the whole, and then a spray drying apparatus (MDL-050M, manufactured by Fujisaki Electric Co., Ltd.) was used. Then, it was subjected to spray drying to obtain a granulated body E6. The obtained granule E6 was calcined at 700 ° C. for 1 hour in an argon hydrogen atmosphere (hydrogen concentration: 3%), and lithium cobalt phosphate particles carrying 2.0% by mass of cellulose nanofiber-derived carbon were supported. (Li _1.2 Co _0.9 PO ₄ , amount of carbon = 2.0 mass%, average particle size: 100 nm) was obtained.
Hereinafter, the lithium-based polyanion particles are referred to as LCP / C-2.

[Production Example 7: Production of Li _2.2 Co _0.9 SiO ₄ / C particles]
930 g of Li ₂ CO ₃ , 1100 g of silicic acid, 2585 g of Mn (CH ₃ COO) ₂ .4H ₂ O and 3.75 L of water were mixed with a ball mill to obtain slurry A7. Next, the slurry A7 was filtered and dried to obtain a powder mixture B7. The obtained powder mixture B7 was fired at 700 ° C. for 10 hours in an N ₂ atmosphere. After the solid-phase reaction, it was washed with 12 parts by mass of water with respect to 1 part by mass of the produced crystal. The washed crystal was lyophilized at −50 ° C. for 12 hours to obtain Complex C7. 500 g of the obtained composite C7 was collected, and 112 g of cellulose nanofiber (Wma-1202, manufactured by Sugino Machine Co., Ltd., fiber diameter: 4 nm to 20 nm) and 500 mL of water were added thereto to obtain a slurry D7. The obtained slurry D7 was dispersed with an ultrasonic stirrer (T25, manufactured by IKA) for 1 minute to uniformly color the whole, and then spray-dried (MDL-050M, manufactured by Fujisaki Electric Co., Ltd.). And then subjected to spray drying to obtain a granulated body E7. The obtained granule E7 was calcined at 650 ° C. for 1 hour in an argon hydrogen atmosphere (hydrogen concentration: 3%), and cobalt lithium lithium silicate on which 2.0% by mass of cellulose nanofiber-derived carbon was supported. Particles (Li _2.2 Co _0.9 SiO ₄ , amount of carbon = 2.0 mass%, average particle size: 50 nm) were obtained.
Hereinafter, the lithium-based polyanion particles are referred to as LCS / C-2.

[Production Example 8: Production of Na-NCM composite oxide particles having no concentration gradient]
After mixing 263 g of nickel sulfate hexahydrate, 281 g of cobalt sulfate heptahydrate, 241 g of manganese sulfate pentahydrate, and 3 L of water so that the molar ratio of Ni: Co: Mn is 1: 1: 1 Then, 25% aqueous ammonia was added dropwise to the mixture at a dropping rate of 300 mL / min to obtain a slurry A8 containing a metal composite hydroxide having a pH of 11.
Next, slurry B8 obtained by mixing 53 g of sodium carbonate with slurry A8 is filtered and dried, and then the powder obtained by calcination is baked at 800 ° C. for 5 hours in an air atmosphere and then subjected to main firing. Firing was performed at 800 ° C. for 10 hours in an air atmosphere to obtain secondary particles of Na—NCM composite oxide (NaNi _0.33 Co _0.33 Mn _0.34 O ₂ ). (Average particle size of secondary particles: 10 μm)
Hereinafter, the composite oxide particle is referred to as Na-NCM-1.

[Production Example 9: Production of Na-NCM complex oxide particles having a concentration gradient]
334 g of nickel sulfate hexahydrate, 159 g of cobalt sulfate heptahydrate, 136 g of manganese sulfate pentahydrate, such that the molar ratio of Ni: Co: Mn is 0.53: 0.735: 0.735, and 2.4 L of water was mixed to obtain Ni-poor aqueous solution A9. Further, 142 g of nickel sulfate hexahydrate, 9 g of cobalt sulfate heptahydrate, and 7 g of manganese sulfate pentahydrate so that the molar ratio of Ni: Co: Mn is 0.9: 0.05: 0.05. And 0.6 L of water was mixed and Ni-rich aqueous solution B9 was obtained. While stirring the Ni-rich aqueous solution B9 with a pump, 25% aqueous ammonia was added dropwise at a dropping rate of 300 mL / min to obtain a slurry C9 containing a metal composite hydroxide having a pH of 11. While stirring the resulting slurry C9, the entire amount of the Ni-poor aqueous solution A9 is added, 25% aqueous ammonia is added dropwise to the slurry at a dropping rate of 300 mL / min, and the slurry contains a metal composite hydroxide having a pH of 11 D9 was obtained. Next, the slurry D9 was filtered and dried to obtain a mixture E9 of metal composite hydroxide, and then 21 g of sodium hydroxide was mixed with the mixture E9 by a ball mill to obtain a powder mixture F9. The obtained powder mixture F9 was calcined in an air atmosphere at 840 ° C. for 10 hours, and Ni, Co, and Mn had a concentration gradient (particle centers: Ni-rich, Co, Mn-poor) Na—NCM system Secondary particles (average particle size 10 μm) of composite oxide (average composition: NaNi _0.6 Co _0.2 Mn _0.2 O ₂ ) were obtained.
Hereinafter, the composite oxide particle is referred to as Na-NCM-2.

[Production Example 10: Production of Na-NCA composite oxide particles]
530 g of sodium carbonate, 950 g of nickel carbonate, 150 g of cobalt carbonate, 58 g of aluminum carbonate, and 3 L of water were mixed so that the molar ratio of Na: Ni: Co: Al was 1: 0.8: 0.15: 0.05. Then, it was mixed with a ball mill to obtain a powder mixture A10. The obtained powder mixture A10 was calcined at 800 ° C. for 5 hours in an air atmosphere and pulverized, and then calcined in an air atmosphere at 800 ° C. for 24 hours as a main firing, to obtain an NCA-based composite oxide (NaNi _0. Secondary particles of ₈ Co _0.15 Al _0.05 O ₂ ) were obtained. (Average particle size of secondary particles: 10 μm)
Hereinafter, the composite oxide particles are referred to as Na-NCA.

[Production Example 11: Production of NaCoPO ₄ / C particles]
A slurry A11 was obtained by mixing 1213 g of NaOH and 4 L of water. While stirring the slurry A11 at a temperature of 25 ° C. for 3 minutes, 1153 g of 85% phosphoric acid aqueous solution was added dropwise at 35 mL / min, and then 707 g of cellulose nanofiber (Cerish® KY-100G) was added. Then, the mixture was stirred at a stirring speed of 400 rpm for 12 hours to obtain slurry B11 containing trisodium phosphate. Next, 2108 g of CoSO ₄ .7H ₂ O was added to the total amount of the obtained slurry B11 to obtain a slurry C11.
Next, the obtained slurry C11 was put into an autoclave and subjected to a hydrothermal reaction at 170 ° C. for 1 hour. The pressure in the autoclave was 0.8 MPa. The produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal. The washed crystal was lyophilized at −50 ° C. for 12 hours to obtain a complex D11. 1000 g of the obtained composite D11 was collected, and 1 L of water was added thereto to make a slurry E11. Then, the slurry E11 was dispersed with an ultrasonic stirrer (T25) for 1 minute to uniformly color the whole. It was.
Slurry E11 showing uniform coloration was spray dried using a spray drying apparatus (MDL-050M) and then calcined at 700 ° C. for 1 hour in an argon hydrogen atmosphere (hydrogen concentration 3%). NaCoPO ₄ particles (carbon amount = 1.2% by mass) on which carbon derived from 2% by mass of cellulose nanofiber was supported were obtained. (Average particle size of primary particles: 100 nm)
Hereinafter, the sodium-based polyanion particle is referred to as NCP / C-1.

[Production Example 12: Production of Na ₂ CoSiO ₄ / C particles]
A slurry A12 was obtained by mixing 408 g of NaOH, 1397 g of Na ₄ SiO ₄ .nH ₂ O, and 3.75 L of water. To slurry A12, 1054 g of CoSO ₄ · 7H ₂ O and 784 g of cellulose nanofiber (Cerish (registered trademark) KY-100G) were added and stirred to obtain slurry B12.
Next, the obtained slurry B12 was put into an autoclave and subjected to a hydrothermal reaction at 150 ° C. for 12 hours. The pressure in the autoclave was 0.4 MPa. The produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal. The washed crystals were lyophilized at −50 ° C. for 12 hours to obtain Complex C12. 500 g of the obtained composite C12 was collected, and 500 mL of water was added thereto to form a slurry D12. Then, the slurry D12 was subjected to a dispersion treatment with an ultrasonic stirrer (T25) for 1 minute to uniformly color the whole. It was.
2. The slurry D12 exhibiting uniform coloration is spray-dried using a spray drying apparatus (MDL-050M), and then calcined at 650 ° C. for 1 hour in an argon hydrogen atmosphere (hydrogen concentration: 3%). Na ₂ CoSiO ₄ particles (carbon amount = 3.0% by mass) on which 0% by mass of cellulose nanofiber-derived carbon was supported were obtained. (Average particle size of primary particles: 40 nm)
Hereinafter, the sodium-based polyanion particles are referred to as NCS / C-1.

[Production Example 13: Production of Na _1.2 Co _0.9 PO ₄ / C particles]
744 g of Na ₂ CO _3, 2402 g of (NH ₄ ) ₃ PO ₄ .3H ₂ O, 2643 g of Co (CH ₃ COO) ₂ .4H ₂ O, and 4 L of water were mixed with a ball mill to obtain slurry A13. Next, the slurry A13 was filtered and dried to obtain a powder mixture B13. The obtained powder mixture B11 was fired at 700 ° C. for 10 hours in an N ₂ atmosphere. 1000 g of the obtained composite C13 was collected, and 224 g of cellulose nanofiber (Wma-1202, manufactured by Sugino Machine Co., Ltd., fiber diameter: 4 to 20 nm) and 1 L of water were added thereto to obtain slurry D13. The obtained slurry D13 was subjected to dispersion treatment with an ultrasonic stirrer (T25, manufactured by IKA) for 1 minute to uniformly color the whole, and then a spray dryer (MDL-050M, manufactured by Fujisaki Electric Co., Ltd.) was used. Then, it was subjected to spray drying to obtain a granulated body E13. The obtained granulated body E13 was calcined at 700 ° C. for 1 hour in an argon hydrogen atmosphere (hydrogen concentration 3%), and cobalt sodium phosphate particles carrying 2.0% by mass of cellulose nanofiber-derived carbon (Na _1.2 Co _0.9 PO ₄ , amount of carbon = 2.0 mass%, average particle size: 100 nm) was obtained.
Hereinafter, the sodium-based polyanion particles are referred to as NCP / C-2.

[Production Example 14: Production of Na _2.2 Co _0.9 SiO ₄ / C particles]
1334 g of Na ₂ CO ₃ , 1100 g of silicic acid, 2585 g of Mn (CH ₃ COO) ₂ .4H ₂ O, and 3.75 L of water were mixed with a ball mill to obtain slurry A14. Next, the slurry A14 was filtered and dried to obtain a powder mixture B14. The obtained powder mixture B14 was fired at 700 ° C. for 10 hours in an N ₂ atmosphere. 500 g of the obtained composite C14 was collected, and 112 g of cellulose nanofiber (Wma-1202, manufactured by Sugino Machine Co., Ltd., fiber diameter: 4 to 20 nm) and 500 mL of water were added thereto to obtain slurry D14. The obtained slurry D14 was subjected to dispersion treatment with an ultrasonic stirrer (T25, manufactured by IKA) for 1 minute to uniformly color the whole, and then a spray dryer (MDL-050M, manufactured by Fujisaki Electric Co., Ltd.) was used. Then, it was subjected to spray drying to obtain a granulated body E14. The obtained granulated body E14 was calcined at 650 ° C. for 1 hour in an argon hydrogen atmosphere (hydrogen concentration: 3%), and cobalt sodium silicate particles on which 2.0% by mass of cellulose nanofiber-derived carbon was supported (Na _2.2 Co _0.9 SiO ₄ , amount of carbon = 2.0 mass%, average particle diameter: 50 nm) was obtained.
Hereinafter, the sodium-based polyanion particle is referred to as NCS / C-2.

[Example 1: Li-NCM-1 95% + LiCoPO ₄ 5% complex]
A slurry a1 was obtained by mixing 0.64 g of LiOH.H ₂ O and 30 mL of water. While maintaining the slurry a1 at a temperature of 25 ° C. for 3 minutes, 0.57 g of 85% phosphoric acid aqueous solution is dropped at 35 mL / min, and stirred at a stirring speed of 400 rpm for 12 hours to contain trilithium phosphate. A slurry b1 was obtained. Next, 1.41 g of CoSO ₄ · 7H ₂ O and 15.7 g of Li-NCM-1 obtained in Production Example 1 were added to the total amount of the obtained slurry b1 to obtain a slurry c1.
Next, the obtained slurry c1 was put into an autoclave and subjected to a hydrothermal reaction at 150 ° C. for 1 hour. The pressure in the autoclave was 0.4 MPa. The produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal. The washed crystal was freeze-dried at −50 ° C. for 12 hours, and a composite (Li-NCM-1 / LiCoPO ₄ ) in which Li-NCM-1 and LiCoPO ₄ were combined on the surface and internal voids of the secondary particles. = 95/5). (Average particle size of secondary particles: 11 μm)

[Example 2: Li-NCM-1 95% + Li ₂ CoSiO ₄ 5% composite]
LiOH.H ₂ O 0.21 g, Na ₄ SiO ₄ .nH ₂ O 0.69 g, Li-NCM-1 8.0 g obtained in Production Example 1 and water 30 mL were mixed to obtain slurry a2. To the slurry a2, 0.70 g of CoSO ₄ .7H ₂ O was added, followed by stirring to obtain a slurry b2.
Subsequently, the obtained slurry b2 was put into an autoclave and subjected to a hydrothermal reaction at 150 ° C. for 12 hours. The pressure in the autoclave was 0.4 MPa. The produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal. It washed crystals for 12 hours freeze drying at -50 ° C. The secondary at the surface and internal voids of the particles, Li-NCM-1 and _Li 2 CoSiO ₄ and is formed by composite Li-NCM-1 and _Li 2 CoSiO ₄ composite (Li-NCM-1 / Li ₂ CoSiO ₄ = 95/5) was obtained. (Average particle size of secondary particles: 11 μm)

[Example 3: Li-NCM-2 95% + LiCoPO ₄ 5% complex]
In the same manner as in Example 1 except that 15.7 g of Li-NCM-2 obtained in Production Example 2 was used instead of Li-NCM-1, Li-NCM-2 and LiCoPO ₄ and was obtained complex of Li-NCM-2 and LiCoPO ₄ formed by composing the (Li-NCM-2 / LiCoPO 4 = 95/5). (Average particle size of secondary particles: 11 μm)

[Example 4: Li-NCM-2 95% + Li ₂ CoSiO ₄ 5% composite]
In the same manner as in Example 2, except that 8.0 g of Li-NCM-2 obtained in Production Example 2 was used instead of Li-NCM-1, Li-NCM-2 and the _Li 2 CoSiO ₄ was obtained a complex of Li-NCM-2 and _Li 2 CoSiO ₄ formed by composite _{(Li-NCM-2 / Li} 2 CoSiO 4 = 95/5). (Average particle size of secondary particles: 11 μm)

[Example 5: Li-NCM-1 95% + Li _1.2 Co _0.9 PO ₄ 5% complex]
Li-NCM-1 and Li _1.2 Co _0.9 PO ₄ were combined on the surface and internal voids of the secondary particles in the same manner as in Example 1 except that LiOH.H ₂ O was changed to 0.77 g. A composite of Li-NCM-1 and Li _1.2 Co _0.9 PO ₄ (Li-NCM-1 / Li _1.2 Co _0.9 PO ₄ = 95/5) was obtained. (Average particle size of secondary particles: 11 μm)

[Example 6: Li-NCM-1 95% + Li _2.2 Co _0.9 PO ₄ 5% complex]
Li-NCM-1 and Li _2.2 Co _0.9 PO ₄ are combined on the surface and internal voids of the secondary particles in the same manner as in Example 2 except that LiOH.H ₂ O is 0.23 g. As a result, a composite of Li-NCM-1 and Li _2.2 Co _0.9 PO ₄ (Li-NCM-1 / Li _2.2 Co _0.9 PO ₄ = 95/5) was obtained. (Average particle size of secondary particles: 11 μm)

[Example 7: Li-NCA 95% + LiCoPO ₄ 5% complex]
A slurry a7 was obtained by mixing 0.64 g of LiOH.H ₂ O and 30 mL of water. While stirring slurry a7 at a temperature of 25 ° C. for 2 to 3 minutes, 0.57 g of 85% aqueous phosphoric acid solution was added dropwise at 35 mL / min, and the mixture was stirred for 12 hours at a speed of 400 rpm. A mixed solution b7 was obtained. Next, 1.41 g of CoSO ₄ .7H ₂ O and 15.7 g of Li—NCA obtained in Production Example 3 were added to the total amount of the mixed liquid b7 containing the obtained trilithium phosphate, and the mixed liquid c7 Got.
Subsequently, the obtained mixed liquid c7 was put into an autoclave, and a hydrothermal reaction was performed at 150 ° C. for 1 hour. The pressure in the autoclave was 0.4 MPa. The produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal. The washed crystal is freeze-dried at −50 ° C. for 12 hours, and a composite of Li—NCA and LiCoPO ₄ complexed on the surface and internal voids of the secondary particles (Li—NCA / LiCoPO ₄ = 95/5). Got. (Average particle size of secondary particles: 11 μm)

[Example 8: Li-NCA 95% + Li ₂ CoSiO ₄ 5% composite]
LiOH · H ₂ O 0.21g, was obtained _{Na 4 SiO 4 · nH 2 O} 0.69g, and Li-NCA 8.00 g in a mixture of ultra-pure water 30mL slurry a8 of Preparation 3. To the slurry a8, 0.70 g of CoSO ₄ .7H ₂ O was added and mixed to obtain a mixed solution b8.
Subsequently, the obtained mixed liquid b8 was put into an autoclave, and a hydrothermal reaction was performed at 150 ° C. for 12 hours. The pressure in the autoclave was 0.4 MPa. The produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal. The washed crystals were 12 hours freeze drying at -50 ° C., the surface and internal voids of the secondary particles, the complex of Li-NCA and _Li 2 CoSiO ₄ of the Li-NCA and _Li 2 CoSiO ₄ is formed by composite (Li-NCA / Li ₂ CoSiO ₄ = 95/5) was obtained. (Average particle size of secondary particles: 11 μm)

[Example 9: Li-NCM-1 47.5% + Li-NCA 47.5% + LiCoPO ₄ 5% complex]
Li-NCM-1 was used in the same manner as in Example 1 except that 7.85 g of Li-NCM-1 was used and 7.85 g of Li-NCA obtained in Production Example 3 was used. , a complex of Li-NCM-1, Li- NCA and LiCoPO ₄ of the Li-NCA and LiCoPO ₄ is formed by composite _{(Li-NCM-1 / Li} -NCA / LiCoPO 4 = 47.5 / 47.5 / 5) was obtained. (Average particle size of secondary particles: 11 μm)

[Example 10: Li-NCM-1 47.5% + Li-NCA 47.5% + Li ₂ CoSiO ₄ 5% composite]
Li-NCM-1, Li-NCA and Li ₂ CoSiO ₄ were combined in the same manner as in Example 2 except that 4 g of Li-NCM-1 was used and 4 g of Li-NCA obtained in Production Example 3 was used. A composite of Li-NCM-1, Li-NCA and Li ₂ CoSiO ₄ (Li-NCM-1 / Li-NCA / Li ₂ CoSiO ₄ = 47.5 / 47.5 / 5) was obtained. (Average particle size of secondary particles: 11 μm)

[Example 11: Na-NCM-1 95% + NaCoPO ₄ 5% complex]
A slurry a11 was obtained by mixing 0.61 g of NaOH and 30 mL of water. While maintaining the slurry a11 at a temperature of 25 ° C. for 3 minutes, 0.57 g of 85% aqueous phosphoric acid solution was added dropwise at 35 mL / min and stirred at a stirring speed of 400 rpm for 12 hours to contain trisodium phosphate. A slurry b11 was obtained. Next, 1.41 g of CoSO ₄ .7H ₂ O and 15.7 g of Na—NCM-1 obtained in Production Example 8 were added to the total amount of the slurry b11, thereby obtaining a slurry c11.
Next, the obtained slurry c11 was put into an autoclave and subjected to a hydrothermal reaction at 150 ° C. for 1 hour. The pressure in the autoclave was 0.4 MPa. The produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal. The washed crystal was freeze-dried at −50 ° C. for 12 hours, and a complex (Na-NCM-1 / NaCoPO ₄ ) in which Na—NCM-1 and NaCoPO ₄ were complexed on the surface and internal voids of the secondary particles. = 95/5). (Average particle size of secondary particles: 11 μm)

[Example 12: Na-NCM-1 95% + Na ₂ CoSiO ₄ 5% composite]
A slurry a2 was obtained by mixing 0.20 g of NaOH, 0.69 g of Na ₄ SiO ₄ .nH ₂ O, 8.0 g of Na-NCM-1 obtained in Production Example 8, and 30 mL of water. To the slurry a2, 0.70 g of CoSO ₄ .7H ₂ O was added, followed by stirring to obtain a slurry b2.
Subsequently, the obtained slurry b2 was put into an autoclave and subjected to a hydrothermal reaction at 150 ° C. for 12 hours. The pressure in the autoclave was 0.4 MPa. The produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal. The washed crystals were freeze-dried at −50 ° C. for 12 hours, and Li—NCM-1 and Na ₂ CoSiO formed by complexing Na—NCM-1 and Na ₂ CoSiO _{4 on} the surfaces and internal voids of the secondary particles. ₄ conjugates _{(Li-NCM-1 / Na} 2 CoSiO 4 = 95/5) was obtained. (Average particle size of secondary particles: 11 μm)

[Example 13: Na-NCM-2 95% + NaCoPO ₄ 5% complex]
In the same manner as in Example 11 except that 15.7 g of Na-NCM-2 obtained in Production Example 9 was used instead of Na-NCM-1, Na-NCM-2 and NaCoPO ₄ and was obtained complex of Na-NCM-2 and NaCoPO ₄ formed by composing the (Na-NCM-2 / NaCoPO 4 = 95/5). (Average particle size of secondary particles: 11 μm)

[Example 14: Na-NCM-2 95% + Na ₂ CoSiO ₄ 5% composite]
In the same manner as in Example 12 except that 8.0 g of Na-NCM-2 obtained in Production Example 9 was used instead of Na-NCM-1, Na-NCM-2 and the _Na 2 CoSiO ₄ was obtained a complex of Na-NCM-2 and _Na 2 CoSiO ₄ formed by composite _{(Na-NCM-2 / Na} 2 CoSiO 4 = 95/5). (Average particle size of secondary particles: 11 μm)

[Example 15: Na-NCM-1 95% + Na _1.2 Co _0.9 PO ₄ 5% complex]
Na formed by combining Na—NCM-1 and Na _1.2 Co _0.9 PO _{4 on} the surface and internal voids of the secondary particles in the same manner as in Example 11 except that NaOH was changed to 0.73 g. A complex of NCM-1 and Na _1.2 Co _0.9 PO ₄ (Na-NCM-1 / Na _1.2 Co _0.9 PO ₄ = 95/5) was obtained. (Average particle size of secondary particles: 11 μm)

[Example 16: Na-NCM-1 95% + Na _2.2 Co _0.9 PO ₄ 5% complex]
Na formed by combining Na-NCM-1 and Na _2.2 Co _0.9 PO _{4 on} the surface and internal voids of the secondary particles in the same manner as in Example 12 except that NaOH was changed to 0.22 g. -A composite of NCM-1 and Na _2.2 Co _0.9 PO ₄ (Na-NCM-1 / Na _2.2 Co _0.9 PO ₄ = 95/5) was obtained. (Average particle size of secondary particles: 11 μm)

[Example 17: Na-NCA 95% + NaCoPO ₄ 5% complex]
A slurry a17 was obtained by mixing 0.61 g of NaOH and 30 mL of water. While maintaining the slurry a17 at a temperature of 25 ° C. for 2 to 3 minutes while stirring, 0.57 g of 85% phosphoric acid aqueous solution was dropped at 35 mL / min, and the mixture was stirred for 12 hours at a speed of 400 rpm. A mixed solution b17 was obtained. Next, 1.41 g of CoSO ₄ .7H ₂ O and 15.7 g of Na—NCA obtained in Production Example 10 are added to the total amount of the mixed liquid b17 containing the obtained trisodium phosphate, and the mixed liquid c17 Got.
Next, the obtained mixed liquid c17 was put into an autoclave and subjected to a hydrothermal reaction at 150 ° C. for 1 hour. The pressure in the autoclave was 0.4 MPa. The produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal. The washed crystal is lyophilized at −50 ° C. for 12 hours, and a complex formed by complexing Na—NCA and NaCoPO _{4 at} the surface and internal voids of the secondary particles (Na—NCA / NaCoPO ₄ = 95/5). Got. (Average particle size of secondary particles: 11 μm)

[Example 18: Li-NCA 95% + Li ₂ CoSiO ₄ 5% composite]
A slurry a18 was obtained by mixing 0.20 g of NaOH, 0.69 g of Na ₄ SiO ₄ .nH ₂ O, and 8 g of Na—NCA of Production Example 10 with 30 mL of ultrapure water. To the slurry a18, 0.70 g of CoSO ₄ .7H ₂ O was added and mixed to obtain a mixed solution b18.
Subsequently, the obtained mixed liquid b18 was put into an autoclave, and a hydrothermal reaction was performed at 150 ° C. for 12 hours. The pressure in the autoclave was 0.4 MPa. The produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal. The washed crystals were 12 hours freeze drying at -50 ° C., the surface and internal voids of the secondary particles, a complex of Na-NCA and _Na 2 CoSiO ₄ of the Na-NCA and _Na 2 CoSiO ₄ is formed by composite (Na—NCA / Na ₂ CoSiO ₄ = 95/5) was obtained. (Average particle size of secondary particles: 11 μm)

[Example 19: Na-NCM-1 47.5% + Na-NCA 47.5% + NaCoPO ₄ 5% complex]
Na-NCM-1 was used in the same manner as in Example 11, except that 7.85 g of Na-NCM-1 was used and 7.85 g of Na-NCA obtained in Production Example 10 was used. , a complex of Na-NCM-1, Na- NCA and NaCoPO ₄ of the Na-NCA and NaCoPO ₄ is formed by composite _{(Na-NCM-1 / Na} -NCA / NaCoPO 4 = 47.5 / 47.5 / 5) was obtained. (Average particle size of secondary particles: 11 μm)

[Example 20: Na-NCM-1 47.5% + Na-NCA 47.5% + Na ₂ CoSiO ₄ 5% composite]
Na-NCM-1, Na-NCA and Na ₂ CoSiO ₄ were combined in the same manner as in Example 12 except that 4 g of Na-NCM-1 was used and 4 g of Na-NCA obtained in Production Example 10 was used. A composite of Na-NCM-1, Na-NCA and Na ₂ CoSiO ₄ (Na-NCM-1 / Na-NCA / Na ₂ CoSiO ₄ = 47.5 / 47.5 / 5) was obtained. (Average particle size of secondary particles: 11 μm)

[Comparative Example 1: Li-NCM-1 95% + LCP / C-1 5% aggregate]
475 g of Li-NCM-1 obtained in Production Example 1 and 25 g of LCP / C-1 obtained in Production Example 4 were used at 20 m / s (3000 rpm) for 5 minutes using Nobilta (Hosokawa Micron Corporation, NOB130). , An agglomerate obtained by mixing Li-NCM-1 and LCP / C-1 only on the surface of each other (Li-NCM-1 / LCP / C-1) = 95/5). (Average particle size of secondary particles: 13 μm)

[Comparative Example 2: Li-NCM-1 95% + LCS / C-1 5% aggregate]
In place of LCP / C-1, except that LCS / C-1 obtained in Production Example 5 was used, mixing was performed while applying compressive force and shearing force in the same manner as in Comparative Example 1, and Li-NCM The aggregate (Li-NCM-1 / LCS / C-1 = 95/5) formed by combining -1 and LCS / C-1 only on the surfaces of each other was obtained. (Average particle size of secondary particles: 13 μm)

[Comparative Example 3: Li-NCM-2 95% + LCP / C-1 5% aggregate]
In place of Li-NCM-1, Li-NCM-2 obtained in Production Example 2 was used, and mixed in the same manner as Comparative Example 1 while applying compressive force and shearing force. Aggregates (Li-NCM-2 / LCP / C-1 = 95/5) formed by complexing 2 and LCP / C-1 only on the surfaces of each other were obtained. (Average particle size of secondary particles: 13 μm)

[Comparative Example 4: Li-NCM-2 95% + LCS / C-1 5% aggregate]
A comparison was made except that Li-NCM-2 obtained in Production Example 2 was used instead of Li-NCM-1, and LCS / C-1 obtained in Production Example 5 was used instead of LCP / C-1. In the same manner as in Example 1, agglomerates (Li-NCM-2) formed by mixing Li-NCM-2 and LCS / C-1 only on the surface of each other by mixing while applying compressive force and shearing force. / LCS / C-1 = 95/5). (Average particle size of secondary particles: 13 μm)

[Comparative Example 5: Li-NCM-1 95% + LCP / C-2 5% aggregate]
Instead of LCP / C-1, LCP / C-2 obtained in Production Example 6 was used, and the mixture was mixed while applying compressive force and shearing force in the same manner as in Comparative Example 1, and Li-NCM The aggregate (Li-NCM-1 / LCP / C-2 = 95/5) formed by combining -1 and LCP / C-2 only on the surface of each other was obtained. (Average particle size of secondary particles: 13 μm)

[Comparative Example 6: Li-NCM-1 95% + LCS / C-2 5% aggregate]
In place of LCP / C-1, except that LCS / C-2 obtained in Production Example 7 was used, mixing was performed while applying compressive force and shearing force in the same manner as in Comparative Example 1, and Li-NCM The aggregate (Li-NCM-1 / LCS / C-2 = 95/5) formed by combining -1 and LCS / C-2 only on the surfaces of each other was obtained. (Average particle size of secondary particles: 13 μm)

[Comparative Example 7: Li-NCA 95% + LCP / C-1 5% aggregate]
Instead of Li-NCM-1, except that Li-NCA obtained in Production Example 3 was used, mixing was performed while applying compressive force and shearing force in the same manner as in Comparative Example 1, and Li-NCA and LCP / Aggregates (Li-NCA / LCP / C-1 = 95/5) formed by complexing with C-1 only on the surfaces of each other were obtained. (Average particle size of secondary particles: 13 μm)

[Comparative Example 8: Li-NCA 95% + LCS / C-1 5% aggregate]
Comparative Example 1 except that Li-NCA obtained in Production Example 3 was used instead of Li-NCM-1, and LCS / C-1 obtained in Production Example 5 was used instead of LCP / C-1. In the same manner as described above, an agglomerate (Li-NCA / LCS / C-1) formed by mixing Li-NCA and LCS / C-1 only on the surface of each other by mixing while applying compressive force and shearing force. = 95/5). (Average particle size of secondary particles: 13 μm)

[Comparative Example 9: Li-NCM-1 47.5% + Li-NCA 47.5% + LCP / C-1 5% aggregate]
In the same manner as in Comparative Example 1 except that 237.5 g of Li-NCM-1 was used and 237.5 g of Li-NCA obtained in Production Example 3 was used, mixing was performed while applying compressive force and shearing force. -Aggregates formed by complexing NCM-1, Li-NCA, and LCP / C-1 only on the surface of each other (Li-NCM-1 / Li-NCA / LCP / C-1 = 47.5 / 47 .5 / 5) was obtained. (Average particle size of secondary particles: 13 μm)

[Comparative Example 10: Li-NCM-1 47.5% + Li-NCA 47.5% + LCS / C-1 5% aggregate]
237.5 g of Li-NCM-1 was used, 237.5 g of Li-NCA obtained in Production Example 3 was used, and LCS / C-1 obtained in Production Example 5 was used instead of LCP / C-1. Except for the above, in the same manner as in Comparative Example 1, mixing was performed while applying compressive force and shearing force, and Li-NCM-1, Li-NCA, and LCS / C-1 were combined only on the surface of each other. Aggregates (Li-NCM-1 / Li-NCA / LCS / C-11 = 47.5 / 47.5 / 5) were obtained. (Average particle size of secondary particles: 13 μm)

[Comparative Example 11: Na-NCM-1 95% + NCP / C-1 5% aggregate]
475 g of Na-NCM-1 obtained in Production Example 8 and 25 g of NCP / C-1 obtained in Production Example 11 were used at 20 m / s (3000 rpm) for 5 minutes using Nobilta (Hosokawa Micron Corporation, NOB130). , An agglomerate formed by mixing Na-NCM-1 and NCP / C-1 only on the surface of each other (Na-NCM-1 / NCP / C-1) = 95/5). (Average particle size of secondary particles: 13 μm)

[Comparative Example 12: Na-NCM-1 95% + NCS / C-1 5% aggregate]
In place of NCP / C-1, except that NCS / C-1 obtained in Production Example 12 was used, mixing was performed while applying compressive force and shearing force in the same manner as in Comparative Example 11, and Na-NCM An aggregate (Na-NCM-1 / NCS / C-1 = 95/5) obtained by combining -1 and NCS / C-1 only on the surface of each other was obtained. (Average particle size of secondary particles: 13 μm)

[Comparative Example 13: Na-NCM-2 95% + NCP / C-1 5% aggregate]
Instead of Na-NCM-1, except that Na-NCM-2 obtained in Production Example 9 was used, mixing was performed while applying compressive force and shearing force in the same manner as in Comparative Example 11, and Na-NCM- Aggregates (Na-NCM-2 / NCP / C-1 = 95/5) in which 2 and NCP / C-1 were complexed only on the surfaces of each other were obtained. (Average particle size of secondary particles: 13 μm)

[Comparative Example 14: Na-NCM-2 95% + NCS / C-1 5% aggregate]
A comparison was made except that Na-NCM-2 obtained in Production Example 9 was used instead of Na-NCM-1, and NCS / C-1 obtained in Production Example 12 was used instead of NCP / C-1. In the same manner as in Example 11, an aggregate (Na-NCM-2) formed by mixing Na-NCM-2 and NCS / C-1 only on the surface of each other by mixing while applying compressive force and shearing force. / NCS / C-1 = 95/5). (Average particle size of secondary particles: 13 μm)

[Comparative Example 15: Na-NCM-1 95% + NCP / C-2 5% aggregate]
In place of NCP / C-1, except that NCP / C-2 obtained in Production Example 13 was used, mixing was performed while applying compressive force and shearing force in the same manner as in Comparative Example 11, and Na-NCM An aggregate (Na-NCM-1 / NCP / C-2 = 95/5) obtained by combining -1 and NCP / C-2 only on the surface of each other was obtained. (Average particle size of secondary particles: 13 μm)

[Comparative Example 16: Na-NCM-1 95% + NCS / C-2 5% aggregate]
In place of NCP / C-1, except that NCS / C-2 obtained in Production Example 14 was used, mixing was performed while applying compressive force and shearing force in the same manner as in Comparative Example 11, and Na-NCM The aggregate (Na-NCM-1 / NCS / C-2 = 95/5) in which -1 and NCS / C-2 are complexed only on the surfaces of each other was obtained. (Average particle size of secondary particles: 13 μm)

[Comparative Example 17: Na-NCA 95% + NCP / C-1 5% aggregate]
Instead of Na-NCM-1, except that Na-NCA obtained in Production Example 10 was used, mixing was performed while applying compressive force and shearing force in the same manner as in Comparative Example 11, and Na-NCA and NCP / Aggregates (Na-NCA / NCP / C-1 = 95/5) obtained by complexing with C-1 only on the surfaces of each other were obtained. (Average particle size of secondary particles: 13 μm)

[Comparative Example 18: Na-NCA 95% + NCS / C-1 5% aggregate]
Comparative Example 11 except that Na-NCA obtained in Production Example 10 was used instead of Na-NCM-1, and NCS / C-1 obtained in Production Example 12 was used instead of NCP / C-1. In the same manner as above, an agglomerate formed by mixing Na-NCA and NCS / C-1 only on the surface of each other (Na-NCA / NCS / C-1) by mixing while applying compressive force and shearing force. = 95/5). (Average particle size of secondary particles: 13 μm)

[Comparative Example 19: Na-NCM-1 47.5% + Na-NCA 47.5% + NCP / C-1 5% aggregate]
In the same manner as in Comparative Example 11, except that 237.5 g of Na-NCM-1 was used and 237.5 g of Na-NCA obtained in Production Example 10 was used, mixing was performed while applying compressive force and shearing force. -Aggregates formed by complexing NCM-1, Na-NCA and NCP / C-1 only on the surface of each other (Na-NCM-1 / Na-NCA / NCP / C-1 = 47.5 / 47 .5 / 5) was obtained. (Average particle size of secondary particles: 13 μm)

[Comparative Example 20: Na-NCM-1 47.5% + Na-NCA 47.5% + NCS / C-1 5% aggregate]
237.5 g of Na-NCM-1 was used, 237.5 g of Na-NCA obtained in Production Example 10 was used, and NCS / C-1 obtained in Production Example 12 was used instead of NCP / C-1. Except for the above, in the same manner as in Comparative Example 11, mixing was performed while applying compressive force and shearing force, and Na-NCM-1, Na-NCA, and NCS / C-1 were combined only on the surface of each other. Aggregates (Na-NCM-1 / Na-NCA / NCS / C-11 = 47.5 / 47.5 / 5) were obtained. (Average particle size of secondary particles: 13 μm)

≪Calculation of coverage by X-ray photoelectron spectroscopy≫
The composites of Examples 1 to 20 and the aggregates of Comparative Examples 1 to 20 were measured by X-ray photoelectron spectroscopy, and the materials present on their surfaces were analyzed. Specifically, the peak intensity a corresponding to trivalent Ni obtained by analyzing the peak of Ni2p _3/2 derived from NCM-based composite oxide in the obtained X-ray photoelectron spectroscopy spectrum is expressed as P2p or Si2p derived from polyanion. The peak intensity ratio a / b divided by the peak intensity b was calculated. The results are shown in Tables 1 and 2.

≪Observation of coating state by TEM≫
With respect to the positive electrode active material composite for a lithium ion secondary battery of the present invention, it was confirmed that the composite oxide particles and the polyanion particles were composited on the surface and internal voids of the composite oxide secondary particles. Specifically, the element distribution was analyzed by TEM-EDX (JEM-ARM200F manufactured by JEOL Ltd.) for the cross section of the positive electrode active material composite particles for lithium ion secondary batteries of Example 1 and Example 2. .
FIG. 1 shows a TEM photograph and element distribution chart of Example 1, and FIG. 2 shows a TEM photograph and element distribution chart of Example 2.

≪Metal elution amount in electrolyte solution≫
Using the composites of Examples 1 to 20 and the aggregates of Comparative Examples 1 to 20 as positive electrode materials, positive electrodes of lithium ion secondary batteries or sodium ion secondary batteries were produced. Specifically, the obtained composites of Examples 1 to 20, or the aggregates of Comparative Examples 1 to 20, Ketjen Black, and polyvinylidene fluoride were mixed at a mass ratio of 90: 5: 5. N-methyl-2-pyrrolidone was added and kneaded sufficiently to prepare a positive electrode slurry. The positive electrode slurry was applied to a current collector made of an aluminum foil having a thickness of 20 μm using a coating machine, and vacuum dried at 80 ° C. for 12 hours. Thereafter, it was punched into a disk shape of φ14 mm and pressed at 16 MPa for 2 minutes using a hand press to obtain a positive electrode.
Next, a coin-type secondary battery was constructed using the positive electrode. A lithium foil (in the case of a lithium ion secondary battery) or a sodium foil (in the case of a sodium ion battery) punched to φ15 mm was used as the negative electrode. In the electrolyte solution, LiPF ₆ (in the case of a lithium ion secondary battery) or NaPF ₆ (in the case of a sodium ion secondary battery) is mixed with a mixed solvent in which ethylene carbonate and ethyl methyl carbonate are mixed at a volume ratio of 3: 7. Those dissolved at a concentration of 1 mol / L were used. As the separator, a known one such as a polymer porous film such as polypropylene was used. These battery components were assembled and accommodated in a conventional manner in an atmosphere having a dew point of −50 ° C. or lower to obtain a coin-type secondary battery (CR-2032).

The obtained secondary battery was charged. Specifically, the current was 1 CA (170 mA / g in the case of a lithium ion secondary battery, 154 mA / g in the case of a sodium ion secondary battery), and a constant current of voltage 4.5V.
Thereafter, the secondary battery was disassembled, and the taken out positive electrode was washed with dimethyl carbonate and then immersed in an electrolytic solution. In this case, the electrolyte solution was LiPF ₆ (in the case of a lithium ion secondary battery) or NaPF ₆ (in the case of a sodium ion secondary battery) in a mixed solvent in which ethylene carbonate and ethyl methyl carbonate were mixed at a volume ratio of 1: 1. ) Was dissolved at a concentration of 1 mol / L. The electrolyte solution in which the positive electrode was immersed was placed in a sealed container and allowed to stand at 70 ° C. for 1 week.
After standing, the electrolyte solution from which the positive electrode was taken out was filtered through a 0.45 μm discic filter and acid-decomposed with nitric acid. Mn, Co, and Ni derived from Li-NCM composite oxide or Na-NCM composite oxide contained in the acid-decomposed electrolyte were quantified using ICP emission spectroscopy. The results are shown in Tables 3 and 4.

≪Evaluation of high temperature cycle characteristics≫
The high-temperature cycle characteristics were evaluated using the secondary battery manufactured in the evaluation of the amount of metal elution into the electrolytic solution. Specifically, the charging condition is a constant current charging with a current of 0.5 CA (85 mA / g for a lithium ion secondary battery, 77 mA / g for a sodium ion secondary battery) and a voltage of 4.25 V, and a discharging condition. Was a constant current discharge at 0.5 CA and a final voltage of 3.0 V, and the discharge capacity at 0.5 CA was determined. Furthermore, a 100-cycle repeated test under the same charge / discharge conditions was performed, and the capacity retention rate (%) was determined by the following formula (1). All charge / discharge tests were conducted at 45 ° C.
The results are shown in Tables 5 and 6.
Capacity retention (%) = (discharge capacity after 100 cycles) / (discharge capacity after 1 cycle)
× 100 (1)

As is clear from Tables 5 and 6, the lithium ion secondary battery and the sodium ion secondary battery using the composites obtained in the examples as the positive electrode material are the aggregates obtained in the comparative examples as the positive electrode material. Compared with the used lithium ion secondary battery and sodium ion secondary battery, it has a high capacity retention rate, and it turns out that it is excellent in high temperature cycling characteristics.
Further, as is apparent from Tables 3 and 4, the lithium ion secondary battery and the sodium ion secondary battery using the composites obtained in the examples as the positive electrode material are the amount of metal elution from the electrode to the electrolyte solution. There are few, and it turns out that it is excellent also in safety.

Claims (21)

The following formula (I):
LiNi _a Co _b Mn _c M ¹ _x O ₂ (I)
(In the formula (I), M ¹ is Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, 1 or 2 or more elements selected from Bi and Ge are shown, a, b, c, and x are 0.3 ≦ a <1, 0 <b ≦ 0.7, 0 <c ≦ 0.7, (0 ≦ x ≦ 0.3 and 3a + 3b + 3c + (valence of M ¹ ) × x = 3)
Or the following formula (II):
LiNi _d Co _e Al _f M ² _y O ₂ (II)
(In the formula (II), M ² is Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi and One or more elements selected from Ge are shown, d, e, f, and y are 0.4 ≦ d <1, 0 <e ≦ 0.6, 0 <f ≦ 0.3, 0 ≦. (Y ≦ 0.3 and 3d + 3e + 3f + (valence of M ² ) × y = 3)
In the surface and internal voids of one or more of the lithium composite oxide consisting of particles of lithium composite oxide secondary particles represented (A), under following formula (VI):
Li _t Co _j Ni _k M ⁶ _l SiO ₄ (VI)
(In the formula (VI), M ⁶ represents Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. T, j, k, and l are 1.6 ≦ t ≦ 2.4, 0 ≦ j ≦ 1.2, 0 ≦ k ≦ 1.2, 0 ≦ l ≦ 1.2, j + k ≠ 0, and 0.8 ≦ (j + k + l) ≦ 1.2 And t + 2j + 2k + (the valence of M ⁶ ) × l = 4 is shown.)
A lithium-based polyanion particle (B) containing at least one of cobalt and nickel and a lithium composite oxide particle, and the content of the lithium composite oxide secondary particle (A), The positive electrode active material composite for a lithium ion secondary battery having a mass ratio ((A) :( B)) to the content of the lithium-based polyanion particles (B) of 95: 5 to 50:50.   The lithium composite oxide secondary particles (A) form a core-shell structure having a core portion and a shell portion by two or more types of lithium composite oxide particles represented by the formula (I) having different compositions. The positive electrode active material composite for a lithium ion secondary battery according to claim 1. Furthermore, the water-insoluble carbon particles (C) are embedded in the internal voids of the lithium composite oxide secondary particles (A) and supported on the surfaces of the lithium composite oxide secondary particles (A), and Mass ratio ((A): ((B) + (C) of content of lithium composite oxide secondary particles (A) and total content of lithium-based polyanion particles (B) and water-insoluble carbon particles (C)) The positive electrode active material composite for a lithium ion secondary battery according to claim 1 or 2, wherein))) is 95: 5 to 50:50.   The mass ratio ((B) :( C)) between the content of the lithium-based polyanion particles (B) and the content of the water-insoluble carbon particles (C) is 95: 5 to 70:30. The positive electrode active material composite for a lithium ion secondary battery as described.   The positive electrode active material composite for a lithium ion secondary battery according to any one of claims 1 to 4, wherein the lithium composite oxide secondary particles (A) have an average particle size of 1 µm to 25 µm. The positive electrode active material composite for a lithium ion secondary battery according to any one of claims 1 to 5, wherein the lithium ion conductivity of the lithium-based polyanion particles (B) is 1 x ^10-7 S / cm or more. Formula (III) below
NaNi _{a ′} Co _{b ′} Mn _{c ′} M ³ _{p ′} O ₂ (III)
(In the formula (III), M ³ is Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, 1 or 2 or more elements selected from Bi and Ge, a ′, b ′, c ′, and p ′ are 0.3 ≦ a ′ <1, 0 <b ′ ≦ 0.7, 0 < (c ′ ≦ 0.7, 0 ≦ p ′ ≦ 0.3, and 3a ′ + 3b ′ + 3c ′ + (valence of M ³ ) × p ′ = 3).
Or the following formula (IV):
NaNi _{d ′} Co _{e ′} Al _{f ′} M ⁴ _{q ′} O ₂ (IV)
(In the formula (IV), M ⁴ is Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi and 1 or 2 or more elements selected from Ge, d ′, e ′, f ′, q ′ are 0.4 ≦ d ′ <1, 0 <e ′ ≦ 0.6, 0 <f ′ ≦ 0.3, 0 ≦ q ′ ≦ 0.3, and 3d ′ + 3e ′ + 3f ′ + (the valence of M ⁴ ) × q ′ = 3.
In the surface and internal voids of the sodium composite oxide secondary particles (D) composed of one or more kinds of sodium composite oxide particles represented by the following formula (VII):
Na _w Co _{g ′} Ni _{h ′} M ⁹ _{i ′} PO ₄ (VII)
(In formula (VII), M ⁹ represents Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. W, g ′, h ′, and i 'Is 0.8 ≦ w ≦ 1.2, 0 ≦ g ′ ≦ 1.2, 0 ≦ h ′ ≦ 1.2, 0 ≦ i ′ ≦ 0.3, g ′ + h ′ ≠ 0, and 0. 8 ≦ (g ′ + h ′ + i ′) ≦ 1.2 and w + 2g ′ + 2h ′ + (valence of M ⁹ ) × i ′ = 3 is shown.)
Or the following formula (VIII):
Na _x Co _{j ′} Ni _{k ′} M ¹⁰ _{l ′} SiO ₄ (VIII)
(In the formula (VIII), M ¹⁰ represents Fe, Mn, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd. X, j ′, k ′, and l Is 1.6 ≦ x ≦ 2.4, 0 ≦ j ′ ≦ 1.2, 0 ≦ k ′ ≦ 1.2, 0 ≦ l ′ ≦ 1.2, j ′ + k ′ ≠ 0, and 0. 8 ≦ (j ′ + k ′ + l ′) ≦ 1.2 and x + 2j ′ + 2k ′ + (valence of M ¹⁰ ) × l ′ = 4 is shown.)
The sodium-based polyanion particles (E) containing at least either cobalt or nickel and the sodium composite oxide particles are combined, and the content of the sodium composite oxide secondary particles (D), The positive electrode active material composite for sodium ion secondary batteries whose mass ratio ((D) :( E)) with content of sodium-based polyanion particles (E) is 95: 5 to 50:50.   The sodium composite oxide secondary particles (D) form a core-shell structure having a core part and a shell part by two or more kinds of sodium composite oxide particles represented by formula (III) having different compositions. The positive electrode active material composite for sodium ion secondary batteries according to claim 7. Furthermore, the water-insoluble carbon particles (C) are embedded in the internal voids of the sodium composite oxide secondary particles (D) and supported on the surfaces of the sodium composite oxide secondary particles (D), and Mass ratio ((D): ((E) + (C) of content of sodium composite oxide secondary particles (D) and total content of sodium-based polyanion particles (E) and water-insoluble carbon particles (C)) ))) Is 95: 5 to 50:50. The positive electrode active material composite for a sodium ion secondary battery according to claim 7 or 8.   The mass ratio ((E) :( C)) between the content of the sodium-based polyanion particles (E) and the content of the water-insoluble carbon particles (C) is 95: 5 to 70:30. The positive electrode active material composite for sodium ion secondary batteries as described.   11. The positive electrode active material composite for a sodium ion secondary battery according to claim 7, wherein the average particle diameter of the sodium composite oxide secondary particles (D) is 1 μm to 25 μm. 12. The positive electrode active material composite for a sodium ion secondary battery according to claim ⁷ , wherein sodium ion conductivity of the sodium-based polyanion particles (E) is 1 × 10 ⁻⁷ S / cm or more. The peak intensity ratio (Ni2p _3/2 trivalent Ni peak intensity) / (P2p peak intensity) or (Ni2p _3/2 peak intensity) / (Si2p peak intensity) by X-ray photoelectron spectroscopy is 0. The positive electrode active material composite for a lithium ion secondary battery according to any one of claims 1 to 6, or the sodium ion secondary battery according to any one of claims 7 to 12. Positive electrode active material composite. Peak intensity ratio (Ni2p _3/2 trivalent Ni peak intensity) / ((P2p peak intensity) + (C1s peak intensity)) or (Ni2p _3/2 trivalent Ni by X-ray photoelectron spectroscopy) The peak active material composite for a lithium ion secondary battery according to any one of claims 3 to 6, wherein (peak intensity) / ((peak intensity of Si2p) + (peak intensity of C1s)) is 0.1 or less. Or a positive electrode active material composite for a sodium ion secondary battery according to any one of claims 9 to 12.   The lithium ion secondary battery which contains the positive electrode active material composite for lithium ion secondary batteries of Claim 13 or 14 as a positive electrode material, or the positive electrode active material composite for sodium ion secondary batteries of Claim 13 or 14 Sodium ion secondary battery containing as a positive electrode material.   7. The method according to claim 1, further comprising a step of compounding the lithium composite oxide particles and the lithium-based polyanion particles (B) on the surfaces and internal voids of the lithium composite oxide secondary particles (A). Manufacturing method of positive electrode active material composite for lithium ion secondary battery.   The water-insoluble carbon particles (C) are embedded in the internal voids of the lithium composite oxide secondary particles (A), and the water-insoluble carbon particles (C) are supported on the surfaces of the lithium composite oxide secondary particles (A). The manufacturing method of the positive electrode active material composite_body | complex for lithium ion secondary batteries of any one of Claims 3-6 provided with a process.   The method for producing a positive electrode active material composite for a lithium ion secondary battery according to claim 16 or 17, wherein the step of combining is a step performed using a hydrothermal synthesis method.   13. The method according to claim 7, further comprising a step of compounding the sodium composite oxide particles and the sodium-based polyanion particles (E) on the surface and internal voids of the sodium composite oxide secondary particles (D). Of manufacturing positive electrode active material composite for sodium ion secondary battery.   The water-insoluble carbon particles (C) are embedded in the internal voids of the sodium composite oxide secondary particles (D), and the water-insoluble carbon particles (C) are supported on the surfaces of the sodium composite oxide secondary particles (D). The manufacturing method of the positive electrode active material composite_body | complex for sodium ion secondary batteries of any one of Claims 9-12 provided with a process.   The method for producing a positive electrode active material composite for a sodium ion secondary battery according to claim 19 or 20, wherein the step of combining is a step performed using a hydrothermal synthesis method.