JP2006269308A - Positive electrode material for nonaqueous secondary battery, its manufacturing method, and nonaqueous secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive electrode material for a nonaqueous secondary battery capable of improving a cycle characteristic by suppressing degradation of charge and discharge capacity due to repetition of charge and discharge, and of increasing the charge and discharge capacity by lowering an average charge voltage, and to provide its manufacturing method and to provide a nonaqueous secondary battery using it. <P>SOLUTION: This positive electrode material for a nonaqueous secondary battery uses a lithium-manganese-nickel-cobalt-titanium oxide consisting of lithium, manganese, nickel, cobalt, titanium and oxygen. The lithium-manganese-nickel-cobalt-titanium oxide has a layer structure, is designated by Li[Li<SB>[(1-2x-y)/3]</SB>Ni<SB>x</SB>Co<SB>y</SB>Ti<SB>z</SB>Mn<SB>[(2-x-2y-3z)/3]</SB>]O<SB>2</SB>that satisfies the conditions of 0.2<x<0.5, 0<y<0.2, and 0<z≤0.1 and satisfies 1≥2x+y. Its manufacturing method includes: a process of providing a Ni-Co-Ti-Mn composite hydroxide; an oxidation process of providing an oxyhydroxide by oxidizing the oxide; a process of providing a material mixture by mixing the oxyhydroxide with a lithium compound;, and a process of providing a lithium transition metal composite oxide by baking the mixture. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a positive electrode material used for a nonaqueous secondary battery, a method for producing the same, and a nonaqueous secondary battery using the positive electrode material. More specifically, the present invention relates to a positive electrode material used for a non-aqueous secondary battery suitable for a non-aqueous secondary battery for 4 V, a manufacturing method thereof, and a non-aqueous secondary battery using the same.

In general, as shown in FIG. 4, the concept of the non-aqueous secondary battery is that an electrolyte 3 is stored in a container 2 whose interior is partitioned into a first chamber 2a and a second chamber 2b by a separator 1a. The positive electrode 4 is accommodated in the chamber 2 a while being immersed in the electrolytic solution 3, and the negative electrode 5 is accommodated in the second chamber 2 b while being immersed in the electrolytic solution 3. In this non-aqueous secondary battery 1, the positive electrode 4 is obtained by pouring or impregnating a slurry containing an active material on an aluminum mesh plate, and then heating and drying the poultice or impregnated material to attach the active material to the aluminum mesh plate The negative electrode 5 is formed in a plate shape with carbon or metal lithium typified by graphite or the like.
Examples of the active material to be attached to the positive electrode 4, lithium-cobalt composite oxide such as LiCoO ₂ Conventionally, lithium nickel composite oxide such as LiNiO _2, a metal oxide such as lithium manganese composite oxide such as LiMn ₂ O ₄ Is generally used.
Batteries using the lithium cobalt composite oxide are used in most batteries because of their high structural stability. However, cobalt contained in complex oxides has various problems such as high material costs, low reserves, and severe environmental regulations in exhaust and drainage, and further mass production and enlargement of batteries. As a result, the above problem may become serious.

In addition, a battery using the above lithium nickel composite oxide has a large theoretical capacity and an appropriate discharge potential, but on the other hand, a change in charge / discharge potential related to a change in crystal structure that occurs during the charge / discharge process and a progress of charge / discharge cycle. However, a drastic solution has not been made to the decrease in charge / discharge capacity due to the collapse of the crystal structure accompanying the above, and there has been a problem that the characteristic stability and reliability of the battery are insufficient.
Furthermore, the secondary battery using the above lithium manganese composite oxide can charge and discharge at a capacity close to the theoretical capacity, has no danger of explosion due to ignition, and has an unobtainable advantage of extremely high thermal safety. However, there is a problem that the theoretical capacity is slightly inferior to the battery using the other two composite oxides.
On the other hand, in recent years, Li [Li _{[(1-2x) / 3]} Ni _x Mn _{[(2-x) / 3]} ] has been proposed as a solution for solving the above-described problems in the three types of conventionally used active materials. Development of a lithium nickel manganese composite oxide such as O ₂ is underway for practical use (see, for example, Non-Patent Document 1). And in the active material consisting of this lithium nickel manganese composite oxide, the energy density is improved, the cost is reduced, and the safety is enhanced.
Journal of Power Sources, 112,2002,634-638

However, in the active material composed of the above-described conventional lithium nickel manganese composite oxide, although the discharge capacity in the initial stage is large, the expansion and contraction of the crystal accompanying charge / discharge is not sufficiently suppressed, and the regularity of the crystal is also insufficient. Therefore, when charging / discharging is repeated, the charge / discharge capacity is reduced, and the cycle characteristics cannot be sufficiently improved.
Further, when the average charge voltage is high, the discharge capacity tends to be lower than when the average charge voltage is low, and it is preferable to reduce the average charge voltage as much as possible.
An object of the present invention is to provide a positive electrode material for a non-aqueous secondary battery capable of improving cycle characteristics by suppressing a decrease in charge / discharge capacity due to repeated charge / discharge, and a non-aqueous secondary battery using the same. There is to do.
Another object of the present invention is to provide a positive electrode material for a non-aqueous secondary battery capable of increasing the charge / discharge capacity by lowering the average charge voltage, a method for producing the same, and a non-aqueous secondary battery using the same. .

The invention according to claim 1 is an improvement of a positive electrode material for a non-aqueous secondary battery using lithium manganese nickel cobalt titanium oxide composed of lithium, manganese, nickel, cobalt, titanium and oxygen.
The characteristic configuration is that lithium manganese nickel cobalt titanium oxide has a layered structure, and Li [Li _{[(1-2x-y) / 3]} Ni _x Co _y Ti _z Mn _{[(2-x-2y-3z) / 3]} ] O ₂ , satisfying the conditions of 0.2 <x <0.5, 0 <y <0.2 and 0 <z ≦ 0.1, and satisfying the condition of 1 ≧ 2x + y is there.
In the positive electrode material for a non-aqueous secondary battery according to claim 1, the layer structure of the oxide is clean because it contains cobalt, and charging and discharging are repeated by making the relationship between x and y in nickel and cobalt in this way. However, it is possible to suppress a decrease in charge / discharge capacity.
Moreover, in this positive electrode material for non-aqueous secondary batteries, since it contains titanium with a low atomic number, the average charge voltage can be lowered, and the charge / discharge capacity can be improved as compared with the prior art.

Invention, the composition formula _{Li [Li [(1-2x-y} ) / 3] Ni x Co y Ti z Mn [(2-x-2y-3z) / 3]] is represented by O ₂ according to claim 2 And a method for producing a positive electrode material for a non-aqueous secondary battery having a layered structure.
The characteristic point is that a composite hydroxide synthesis step of reacting an aqueous solution of a nickel salt, a cobalt salt, a titanium salt and a manganese salt with a strong alkaline aqueous solution to obtain a Ni-Co-Ti-Mn composite hydroxide, An oxidation step of oxidizing Ni-Co-Ti-Mn composite hydroxide to obtain Ni-Co-Ti-Mn oxyhydroxide, and mixing the Ni-Co-Ti-Mn oxyhydroxide and a lithium compound And a raw material mixing step for obtaining a raw material mixture and a firing step for firing the raw material mixture in the air to obtain a lithium transition metal composite oxide.
In the method for producing a positive electrode material for a non-aqueous secondary battery according to claim 2, Li [Li _{[(1-2x-y) / 3]} Ni _x Co _y Ti _z Mn _{[(2-x-2y-3z) / 3]} ] a layered structure represented by O ₂ , satisfying the conditions of 0.2 <x <0.5, 0 <y <0.2 and 0 <z ≦ 0.1, and satisfying the condition of 1 ≧ 2x + y Lithium manganese nickel cobalt titanium oxide can be obtained relatively easily.
The firing of the raw material mixture in the air is preferably performed at 900 to 1100 ° C., and the nickel salt, cobalt salt, titanium salt and manganese salt are preferably sulfate, nitrate or chloride, respectively.

The invention according to claim 5 is a non-aqueous secondary battery using the positive electrode material for non-aqueous secondary battery according to claim 1.
The invention according to claim 6 is a non-aqueous secondary battery using the positive electrode material for a non-aqueous secondary battery manufactured by the method according to any one of claims 2 to 4.

In the positive electrode material for a non-aqueous secondary battery of the present invention, lithium manganese nickel cobalt titanium oxide has a layered structure and Li [Li _{[(1-2x-y) / 3]} Ni _x Co _y Ti _z Mn _{[(2 −x−2y−3z) / 3]} ] O ₂ , satisfying the conditions of 0.2 <x <0.5, 0 <y <0.2 and 0 <z ≦ 0.1, and 1 ≧ 2x + y is satisfied and cobalt is included, so that the oxide layer structure is clean. By making the relationship between x and y in nickel and cobalt in this way, even if charging / discharging is repeated, a decrease in charge / discharge capacity is suppressed. Will be able to. Moreover, since titanium with a low atomic number is included, the average charge voltage can be lowered, and the charge / discharge capacity can be improved as compared with the prior art.

  Further, a composite hydroxide synthesis step of obtaining an Ni—Co—Ti—Mn composite hydroxide by reacting an aqueous solution of nickel salt, cobalt salt, titanium salt and manganese salt with a strong alkaline aqueous solution, and the Ni—Co— An oxidation process for obtaining a Ni-Co-Ti-Mn oxyhydroxide by oxidizing a Ti-Mn composite hydroxide, and mixing the Ni-Co-Ti-Mn oxyhydroxide and a lithium compound to form a raw material mixture Lithium manganese nickel cobalt titanium oxide can be obtained relatively easily by including a raw material mixing step for obtaining a lithium transition metal composite oxide by firing the raw material mixture in the air. .

Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the lithium secondary battery 10 is a sheet-like laminate in this embodiment, and includes a positive electrode current collector plate 11, a positive electrode 12 including a positive electrode active material, an electrolyte sheet 13, and a negative electrode active material. And a negative electrode current collector plate 15 are laminated in this order. The positive electrode current collector plate 11 is made of an aluminum plate, and the negative electrode current collector plate 15 is made of a copper plate. As the positive electrode active material contained in the positive electrode 12, lithium manganese nickel cobalt titanium oxide composed of lithium, manganese, nickel, cobalt, titanium and oxygen is used for the active material body. As the negative electrode active material contained in the negative electrode 14, a graphite-based active material is used. Furthermore, as the electrolyte sheet 13, a polyethylene oxide sheet containing an electrolytic solution is used.

The lithium manganese nickel cobalt titanium oxide used as the positive electrode material has a layered structure and Li [Li _{[(1-2x-y) / 3]} Ni _x Co _y Ti _z Mn _{[(2-x-2y-3z) / 3]} ] O ₂ . In this case, x satisfies the condition of 0.2 <x <0.5, y satisfies the condition of 0 <y <0.2, and z satisfies the condition of 0 <z ≦ 0.1. That is, x is greater than 0.2 and less than 0.5, y is greater than 0 and less than 0.2, and z is greater than 0 and less than or equal to 0.1. A preferable value of x is more than 0.2 and less than 0.4, and more preferably more than 0.2 and less than 0.3. On the other hand, the preferred value of y is more than 0 and less than 0.1, and more preferably more than 0.02 and less than 0.08. A preferable value of z is more than 0.01 and 0.09 or less, and more preferably more than 0.01 and 0.08 or less.

  Here, x needs to be more than 0.2 and less than 0.5. When x is 0.2 or less, the amount of Ni contributing to heavy discharge is insufficient and the discharge capacity is reduced. This is because, when x is 0.5 or more, the balance with Mn, which mainly maintains the crystal layered structure, is lost, and the cycle characteristics deteriorate. In addition, y needs to be greater than 0 and less than 0.2. The fact that y is 0 indicates that no cobalt is present, and the layered structure of the crystal cannot be cleaned by cobalt. However, the cycle characteristics cannot be improved. Further, if y is 0.2 or more, the amount of Ni contributing to heavy discharge is insufficient and the discharge capacity is reduced. Furthermore, z needs to be greater than 0 and equal to or less than 0.1 because z indicates that no titanium is present, and the average charging voltage cannot be lowered by titanium. This is because if z exceeds 0.1, the amount of Ni contributing to heavy discharge is insufficient and the discharge capacity is reduced.

  Further, the lithium manganese nickel cobalt titanium oxide used as the positive electrode material is required to satisfy the condition of 1 ≧ 2x + y in the relationship between x and y. That is, this condition requires that Ni be less than Mn. This is because if the value of 2x + y is 1 or more, Ni is equal to Mn or Ni is more than Mn, the structural stability is lowered, and the cycle characteristics are deteriorated. At the same time, by satisfying the condition of 1 ≧ 2x + y, the lithium content becomes 1.0 or more, which further increases the structural stability of the crystal and further improves the cycle characteristics.

This method for producing lithium manganese nickel cobalt titanium oxide includes a composite hydroxide synthesis step, an oxidation step, a raw material mixing step, and a firing step. Hereinafter, each step will be described.
(1) The composite hydroxide synthesis step is a step of obtaining a Ni—Co—Ti—Mn composite hydroxide by reacting an aqueous solution of nickel salt, cobalt salt, titanium salt and manganese salt with a strong alkaline aqueous solution. As a salt containing nickel as a cation, considering that it is water-soluble, for example, nickel nitrate, nickel sulfate, nickel chloride and the like can be used. Examples of the salt containing cobalt as a cation include cobalt nitrate, cobalt sulfate, and cobalt chloride. Examples of the salt containing titanium as a cation include titanium nitrate, titanium sulfate, and titanium chloride. Furthermore, as a salt containing manganese as a cation, for example, manganese nitrate, manganese sulfate, manganese chloride, or the like can be used. In particular, it is desirable to use a nitrate as each salt because it is difficult to remain in the resulting composite hydroxide.

  As an aqueous solution of nickel salt, cobalt salt, titanium salt and manganese salt, for example, an aqueous solution prepared by preparing an aqueous solution of each salt and mixing them can be used. The aqueous salt solution is preferably prepared so that the concentration of the salt is 0.5 to 2M from the viewpoint of satisfying both the reactivity and the yield. And if it prepares so that the ratio of Ni, Co, Ti, and Mn contained in the obtained Ni-Co-Ti-Mn composite hydroxide may become a thing according to the composition of the target lithium transition metal composite oxide. Good. For example, a nickel salt, a cobalt salt, a titanium salt, and a manganese salt are mixed so that a molar ratio of Ni: Co: Ti: Mo = 1 to 10: 1 to 20: 1 to 40:30 to 60 is obtained.

  As the strong alkaline aqueous solution, a lithium hydroxide aqueous solution, a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, ammonia water or the like can be used. Among these, it is desirable to use a lithium hydroxide aqueous solution in view of the point that it is difficult to remain in the produced composite hydroxide and a stable concentration can be maintained. When using an aqueous lithium hydroxide solution, it is desirable to use one having a concentration of about 0.5 to 2M. In order to carry out the reaction uniformly, for example, a strong alkaline aqueous solution may be dropped into the aqueous solution containing the salt to carry out the reaction. The reaction is preferably carried out with stirring. In order to obtain the desired particle size, conditions such as the stirring speed, the pH value of the strong alkaline aqueous solution, and the reaction temperature affect the particle size of the resulting Ni-Co-Ti-Mn composite hydroxide. What is necessary is just to set suitably. For example, the pH value of the strong alkaline aqueous solution is desirably adjusted so as to be substantially constant during the reaction, and the value is desirably 11-12. The reaction temperature is preferably 20 to 40 ° C. in order to obtain an appropriate reaction rate.

  (2) The oxidation step is a step of obtaining Ni—Co—Ti—Mn oxyhydroxide by oxidizing the Ni—Co—Ti—Mn composite hydroxide obtained in the aforementioned composite hydroxide synthesis step. . The oxidation method of the Ni—Co—Ti—Mn composite hydroxide is not particularly limited. Note that, in the composite hydroxide synthesis step, the Ni—Co—Ti—Mn composite hydroxide is obtained as a precipitate in an aqueous solution. Therefore, for example, the Ni-Co-Ti-Mn composite hydroxide can be oxidized by maintaining the suspension after the reaction in the composite hydroxide synthesis step in the atmosphere. In this case, in order to promote the oxidation reaction, it is desirable to hold the agitation while bubbling air into the suspension. Moreover, since the oxidation reaction proceeds at room temperature, the suspension may be kept at room temperature. Moreover, according to the said method, since Ni-Co-Ti-Mn oxyhydroxide is obtained as a precipitate, this can be separated by filtration, washed, etc., and used for the next step. In addition, when the particle diameter of the obtained Ni—Co—Ti—Mn oxyhydroxide is small and difficult to filter, for example, aging is performed to maintain the suspension after the reaction at a predetermined temperature. In this case, the particles may be grown and then filtered off. The aging conditions are not particularly limited, but may be performed at a temperature of 40 to 90 ° C. for about 24 hours. As another method, for example, Ni-Co-Ti-Mn oxyhydroxide can be obtained by spray drying the suspension after the reaction.

  (3) The raw material mixing step is a step of obtaining a raw material mixture by mixing the Ni—Co—Ti—Mn oxyhydroxide obtained in the oxidation step described above and a lithium compound. As the lithium compound, lithium hydroxide, lithium carbonate, lithium nitrate, or the like can be used. In particular, it is desirable to use lithium hydroxide because of its high reactivity. Mixing of the Ni—Co—Ti—Mn oxyhydroxide and the lithium compound may be performed by a method used for mixing ordinary powders. Specifically, it may be mixed using, for example, a ball mill, a mixer, a mortar or the like. In addition, the mixing ratio of the Ni—Co—Ti—Mn oxyhydroxide and the lithium compound is such that the composition of the target lithium transition metal composite oxide, that is, Li: (Ni + Co + Ti + Mn) is about 1-1. The ratio may be 3: 1.

(4) The firing step is a step in which the raw material mixture obtained in the raw material mixing step is fired in the air to obtain a lithium transition metal composite oxide. The firing temperature is desirably in the range of 900 to 1100 ° C. This is because if the firing temperature is lower than 900 ° C., the reaction does not proceed sufficiently and the crystallinity is lowered. On the other hand, when the temperature exceeds 1100 ° C., lithium is evaporated, and the composition easily loses lithium. Note that the firing time may be a time sufficient to complete the firing, and is usually performed for about 3 to 10 hours.
In the positive electrode material for a non-aqueous secondary battery manufactured in this way, the volume change accompanying the charge / discharge cycle is small, and the reduction in charge / discharge capacity can be suppressed even when charge / discharge is repeated. Moreover, since this positive electrode material for non-aqueous secondary batteries contains titanium with a low atomic number, the average charging voltage can be lowered. Therefore, when producing a non-aqueous secondary battery by producing a positive electrode using a positive electrode material made of this lithium manganese nickel cobalt titanium oxide and producing a negative electrode using a negative electrode active material made of graphite containing lithium. And the non-aqueous secondary battery which can improve the discharge capacity compared with the past, and can suppress the fall of the charge / discharge capacity even if charging / discharging is repeated can be obtained.

Next, examples of the present invention will be described in detail together with comparative examples.
<Example 1>
First, 2 liters of 1M lithium hydroxide aqueous solution was prepared in a sealed container filled with nitrogen gas. Next, each aqueous solution of 1M nickel nitrate, cobalt nitrate, titanium nitrate, and manganese nitrate is mixed so that the molar ratio of Ni: Co: Ti: Mn is 35: 5: 5: 47, and a 1 liter aqueous solution is obtained. It was. A lithium hydroxide aqueous solution was dropped into this aqueous solution to precipitate a Ni—Co—Ti—Mn composite hydroxide. The reaction temperature was 30 ° C., and the pH value during the reaction was 11-12. The suspension in which the Ni—Co—Ti—Mn composite hydroxide was precipitated was stirred while bubbling air and kept at room temperature for 1 day. Was oxidized into Ni—Co—Ti—Mn oxyhydroxide. Further, the suspension was aged by holding at 80 ° C. for 10 hours, and then the precipitate was separated by filtration and washed with water to obtain Ni—Co—Ti—Mn oxyhydroxide. Next, the obtained Ni—Co—Ti—Mn oxyhydroxide and lithium hydroxide were mixed so that the molar ratio of Li: (Ni + Co + Ti + Mn) was 1: 1, and fired at 1000 ° C. for 5 hours in the air. To obtain a lithium transition metal composite oxide. When the composition of the lithium transition metal composite oxide was confirmed by composition analysis, the composition formula Li ₁ . ₀₈ Ni ₀ . ₃₅ Co ₀ . ₀₅ Ti ₀ . ₀₅ Mn ₀ . It was a lithium transition metal complex oxide represented by ₄₇ O ₂ . This lithium transition metal composite oxide was taken as Example 1.

<Examples 2 and 3>
In the method in Example 1, the mixing ratio of each aqueous solution of nickel nitrate, cobalt nitrate, titanium nitrate, and manganese nitrate, that is, only the ratio of Ni, Co, and Ti contained in the Ni—Co—Ti—Mn composite hydroxide. Two more kinds of different lithium transition metal composite oxides were produced. Among the obtained lithium transition metal composite oxides, the composition formula Li ₁ . A lithium transition metal composite oxide represented by 1Ni _0.3 Co _0.1 Ti _0.07 Mn _0.43 O ₂ is taken as Example 2, and the composition formula is Li1. Example 3 was a lithium transition metal composite oxide represented by ₁₇ Ni _0.2 Co _0.1 Ti _0.01 Mn _0.52 O ₂ .

<Comparative Examples 1-3>
In the method in Example 1, the mixing ratio of each aqueous solution of nickel nitrate, cobalt nitrate, titanium nitrate, and manganese nitrate, that is, only the ratio of Ni, Co, and Ti contained in the Ni—Co—Ti—Mn composite hydroxide. Three more different lithium transition metal complex oxides were produced. Among the obtained lithium transition metal composite oxides, composition formula Li1. _A lithium transition metal composite oxide represented by ₁ Ni _0.3 Co _0.1 Ti ₀ Mn _0.5 O ₂ and z = 0 is set as Comparative Example 1, and the composition formula is Li 1. _A lithium transition metal composite oxide represented by ₁₅ Ni _0.25 Co _0.05 Ti _0.2 Mn _0.35 O ₂ and z exceeding 0.1 is referred to as Comparative Example 2, and the composition formula is Li1. Comparative Example 3 was a lithium transition metal composite oxide represented by ₀ Ni _0.45 Co _0.15 Ti _0.05 Mn _0.35 O ₂ and 2x + y exceeding 1.

<Comparative test 1 and evaluation>
Positive electrodes were produced using the positive electrode materials for secondary batteries of Examples 1 to 3 and Comparative Examples 1 to 3. Specifically, lithium manganese nickel cobalt oxides (positive electrode materials) of Examples 1 to 3 and Comparative Examples 1 to 3 are mixed with a binder and a conductive additive to prepare a slurry, and this slurry is positive electrode by a doctor blade method. After being stretched on a sheet and dried, this positive electrode sheet was laminated on a positive electrode current collector to produce positive electrodes.
These positive electrodes were attached to the charge / discharge cycle test apparatus 21 as shown in FIG. In this device 21, an electrolytic solution 23 (lithium salt dissolved in an organic solvent) is stored in a container 22, and the positive electrode 12 is added to the electrolytic solution 23 together with a negative electrode 14 (metallic lithium) and a reference electrode 24 (metallic lithium). Further, the positive electrode 12, the negative electrode 14, and the reference electrode 24 are electrically connected to a potentiostat 25 (potentiometer), respectively. A charge / discharge cycle test was performed using this apparatus, and the initial discharge capacity and capacity retention rate of each positive electrode were measured. In addition, a capacity | capacitance retention rate means the value which represented the value with respect to the initial stage discharge capacity of% after performing 20 cycles charge / discharge with%. Table 1 shows the initial discharge capacity of the positive electrode, the discharge capacity after 20 cycles, and the capacity retention together with the composition of lithium manganese nickel cobalt oxide.

  As is apparent from Table 1, it can be seen that Comparative Examples 1 to 3 are inferior to Examples 1 to 3 in both discharge capacity and retention rate. On the other hand, in Examples 1-3, it is superior to Comparative Examples 1-3 in both the discharge capacity and its retention rate, and it can be seen that even if charge / discharge is repeated, a decrease in charge / discharge capacity can be suppressed.

<Comparative test 2 and evaluation>
Nonaqueous secondary batteries were produced using the positive electrode active material powders of Examples 1 to 3, and changes in discharge potential with respect to changes in discharge capacity of these secondary batteries were measured. The result is shown in FIG.
As is clear from FIG. 3, it was found that the discharge capacity / potential characteristics of the secondary batteries of Examples 1 to 3 were in a practically excellent range.

The principal part cross-section block diagram of the nonaqueous secondary battery of embodiment of this invention. The apparatus used for the charging / discharging cycle test of the positive electrode material for non-aqueous secondary batteries of an Example and a comparative example. The figure which shows the discharge capacity and electric potential characteristic of the non-aqueous secondary battery produced using the positive electrode active material powder of Examples 1-3. Cross-sectional expansion explanatory drawing which shows the structure of a non-aqueous secondary battery typically.

Explanation of symbols

  10 Non-aqueous secondary battery

Claims (6)

In a positive electrode material for a non-aqueous secondary battery using lithium manganese nickel cobalt titanium oxide composed of lithium, manganese, nickel, cobalt, titanium and oxygen,
The lithium-manganese-nickel-cobalt-titanium oxide is a layered structure _{Li [Li [(1-2x-y} ) / 3] Ni x Co y Ti z Mn [(2-x-2y-3z) / 3]] O ₂ and
Satisfy the conditions of 0.2 <x <0.5, 0 <y <0.2 and 0 <z ≦ 0.1,
And a positive electrode material for a non-aqueous secondary battery, wherein 1 ≧ 2x + y is satisfied. Composition formula _{Li [Li [(1-2x-y} ) / 3] Ni x Co y Ti z Mn [(2-x-2y-3z) / 3]] nonaqueous secondary having represented by layered structure O ₂ A method for producing a positive electrode material for a secondary battery, comprising:
A composite hydroxide synthesis step of reacting an aqueous solution of nickel salt, cobalt salt, titanium salt and manganese salt with a strong alkaline aqueous solution to obtain a Ni-Co-Ti-Mn composite hydroxide;
An oxidation step of oxidizing the Ni-Co-Ti-Mn composite hydroxide to obtain a Ni-Co-Ti-Mn oxyhydroxide;
A raw material mixing step of mixing the Ni-Co-Ti-Mn oxyhydroxide and a lithium compound to obtain a raw material mixture;
A method for producing a positive electrode material for a non-aqueous secondary battery, comprising: calcining the raw material mixture in the air to obtain a lithium transition metal composite oxide. The method for producing a positive electrode material for a non-aqueous secondary battery according to claim 2, wherein the raw material mixture is baked in the atmosphere at 900 to 1100 ° C. The method for producing a positive electrode material for a non-aqueous secondary battery according to claim 2 or 3, wherein the nickel salt, cobalt salt, titanium salt, and manganese salt are sulfate, nitrate, or chloride, respectively. A non-aqueous secondary battery using the positive electrode material for a non-aqueous secondary battery according to claim 1. The non-aqueous secondary battery using the positive electrode material for non-aqueous secondary batteries manufactured by the method of any one of Claims 2 thru | or 4.

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