JP5688128B2 - Lithium manganese phosphate positive electrode active material and method for producing the same - Google Patents

Description

  The present invention relates to a lithium manganese phosphate positive electrode active material capable of expressing high battery properties and a method for producing the same.

  Conventionally, highly conductive substances have been used as positive electrode materials and negative electrode materials in order to improve battery performance. In recent years, next-generation batteries such as lithium ion batteries have been increasingly used, and various positive electrode materials for such batteries have been developed. Lithium manganese phosphate is one of them. Phosphoric acid, manganese compound and water are mixed to make an acidic solution, and lithium hydroxide is added dropwise to make it alkaline and subjected to hydrothermal reaction. An obtained method is known (see Non-Patent Document 1).

Under these circumstances, since lithium manganese phosphate itself has low conductivity, various production methods for effectively utilizing it as a positive electrode active material are known. For example, in Patent Document 1, a lithium-containing composite oxide is manufactured by mixing a solution containing lithium and a solution containing phosphorus, forming a weakly alkaline mixed solution, and dropping the solution into a solution that can contain manganese or the like. A method is disclosed. In Patent Document 2, a precursor mixture containing a Li ⁺ source, a PO ₄ ³⁻ source, a manganese source, and the like is generated, and the obtained precursor mixture is dispersed or pulverized to obtain a LiMPO ₄ compound. A method is disclosed.

JP 2012-211072 A JP 2007-511458 A

Hongmei Ji et al, Elestrochimica Acta 56 (2011), p3093-3100

  However, in any of the methods described in any of the above documents, there is still room for improvement, including what solution should be prepared or what procedure should be manufactured, and the positive electrode capable of sufficiently improving battery physical properties. It has not yet reached the point of obtaining an active material.

  Accordingly, an object of the present invention is to provide a manufacturing method for obtaining a lithium manganese phosphate positive electrode active material capable of expressing excellent battery properties as a positive electrode material for a lithium ion battery, and a lithium manganese phosphate positive electrode obtained by the manufacturing method. To provide an active material.

  Therefore, the present inventors have made various studies and obtained by including a specific step while using slurry water containing a specific amount of transition metal compound and slurry water containing a specific amount of lithium hydroxide. When the lithium manganese phosphate positive electrode active material is used as a positive electrode material of a lithium ion battery, it has been found that the energy density can be effectively increased, and the present invention has been completed.

That is, the present invention contains slurry water (A) containing a transition metal compound containing at least a manganese compound and phosphoric acid in an amount exceeding the solubility in water, and lithium hydroxide in an amount exceeding the solubility in water. Step (I) of preparing slurry water (B)
The obtained slurry water (A) and the slurry water (B) are mixed and cooled while purging with nitrogen to obtain a mixed slurry water (C) (II), and the obtained mixed slurry water (C) is hydrothermally heated. Step (III) of subjecting to pulverization after reaction
The manufacturing method of the lithium manganese phosphate positive electrode active material containing this is provided.
Moreover, this invention provides the lithium manganese phosphate positive electrode active material obtained by the said manufacturing method.

  According to the method for producing a lithium manganese phosphate positive electrode active material of the present invention, a lithium manganese phosphate positive electrode active material capable of effectively increasing the energy density when used as a positive electrode material of a lithium ion battery can be obtained. It is expected to contribute greatly to the realization of a lithium ion battery having good battery properties.

Hereinafter, the present invention will be described in detail.
The method for producing a lithium manganese phosphate positive electrode active material of the present invention includes a slurry water (A) containing a transition metal compound containing at least a manganese compound and phosphoric acid in an amount exceeding the solubility in water, and the solubility in water. Step (I) of preparing slurry water (B) containing lithium hydroxide in an amount exceeding
The obtained slurry water (A) and the slurry water (B) are mixed and cooled while purging with nitrogen to obtain a mixed slurry water (C) (II), and the obtained mixed slurry water (C) is hydrothermally heated. Step (III) of subjecting to pulverization after reaction
including.

  In the step (I), a slurry water containing a transition metal compound containing at least a manganese compound and phosphoric acid in an amount exceeding the solubility in water (the number of g of the transition metal compound dissolved in 100 g of the saturated aqueous solution) and phosphoric acid (A ) Is prepared. That is, in preparing the slurry water (A), water, a transition metal compound in an amount exceeding the solubility in water in the slurry water (A), and phosphoric acid may be mixed. Thus, the slurry water (A) in which the transition metal compound is contained in an excessive amount exceeding the solubility in water is prepared, and this is used together with the slurry water (B) described later, thereby passing through the steps described later. In combination with this, it becomes possible to obtain a lithium manganese phosphate positive electrode active material capable of effectively increasing the energy density in the lithium ion battery.

  As a transition metal (M: M represents a transition metal) compound, at least a manganese compound is used. The manganese compound may be a divalent manganese compound, and examples thereof include manganese halide, manganese sulfate, and manganese acetate. These may be used alone or in combination of two or more. Among these, manganese sulfate is preferably used from the viewpoint of improving battery physical properties.

  Examples of other transition metal (M) compounds include iron compounds. The iron compound may be a divalent iron compound or a hydrate thereof, for example, a halide such as iron halide; a sulfate such as iron sulfate; an organic acid salt such as iron oxalate or iron acetate As well as hydrates thereof. Among these, iron sulfate is preferably used from the viewpoint of improving battery physical properties.

  In the case where the transition metal (M) compound is used in an amount exceeding the solubility in water in the slurry water (A), when the manganese compound is used alone as the transition metal (M) compound, the manganese compound is saturated. What is necessary is just to make it melt | dissolve in water in the quantity exceeding the g number of the manganese compound melt | dissolved in 100 g of aqueous solution, and when using in combination of 2 or more types of transition metal compounds containing a manganese compound as a transition metal (M) compound, manganese Each transition metal compound other than the compound may be dissolved in water in an amount exceeding the number of g of each transition metal compound dissolved in 100 g of the saturated aqueous solution.

  The slurry water (A) contains each transition metal (M) compound in an amount of 2.0 to 5.0 times based on the solubility of each transition metal (M) compound containing at least a manganese compound in water. More preferably 2.5 to 4.5 times the amount of each transition metal (M) compound, more preferably 2.8 to 4.2 times the amount of each transition metal (M). More preferably, it contains a compound.

More specifically, for example, in preparing slurry water (A), when using manganese sulfate as a manganese compound, 79 to 197 parts by mass of manganese sulfate is added to 100 parts by mass of water in slurry water (A). It is preferable to contain, it is more preferable to contain 98-177 mass parts manganese sulfate, and it is still more preferable to contain 110-165 mass parts manganese sulfate. As the manganese sulfate, for example, may be used a hydrate of such MnSO ₄ · 5H ₂ O, in this case, the content is a value obtained by converting the manganese (MnSO ₄₎ weight sulfuric acid.

Furthermore, in preparing slurry water (A), when using iron sulfate as a transition metal (M) compound other than a manganese compound, it is preferable to contain 15 to 40 parts by mass of iron sulfate with respect to 100 parts by mass of water. More preferably, it contains 20 to 35 parts by mass of iron sulfate, and more preferably 22 to 33 parts by mass of iron sulfate. As the iron sulfate, for example, it may be used a hydrate of such FeSO ₄ · 7H ₂ O, in this case, the content is a value obtained by converting the ferrous sulfate (FeSO ₄₎ amount.

  When a manganese compound and an iron compound are used as the transition metal (M) compound, their molar ratio (manganese compound: iron compound) in the slurry water (A) is preferably more than 100: 0 and not more than 51:49, More preferably, it is 99: 1-51: 49, More preferably, it is 95: 5-70: 30, More preferably, it is 90: 10-80: 20.

The slurry water (A) further contains phosphoric acid. Phosphoric acid is so-called orthophosphoric acid (H ₃ PO ₄ ) and is preferably used as an aqueous solution having a concentration of 70 to 90% by mass. The content of phosphoric acid is preferably 60 to 90 parts by mass, more preferably 65 to 85 parts by mass, and still more preferably 68 to 82 parts by mass with respect to 100 parts by mass of water.

  Moreover, when using a manganese compound and an iron compound as a transition metal (M) compound, the total content of these transition metal (M) compounds is preferably 1 mol of phosphoric acid contained in the slurry water (A). The amount is from 0.99 to 1.01 mol, more preferably from 0.995 to 1.005 mol.

  In the step (I), together with the slurry water (A), slurry water (B) containing lithium hydroxide in an amount exceeding the solubility in water (g number of lithium hydroxide dissolved in 100 g of the saturated aqueous solution) is used.

In order to prepare such slurry water (B), water and lithium hydroxide in an amount exceeding the solubility in water may be mixed. Such slurry water (B) preferably contains 2.5 to 5.0 times the amount of lithium hydroxide, based on the solubility of lithium hydroxide in water, and is 3.0 to 4.5 times the amount. More preferably, the lithium hydroxide is contained in an amount of 3.2 to 4.2 times that of lithium hydroxide. Moreover, it is preferable to contain 56-112 mass parts lithium hydroxide with respect to 100 mass parts of water, It is more preferable to contain 67-100 mass parts lithium hydroxide, 71-94 mass parts hydroxylation More preferably, it contains lithium. As the lithium hydroxide, for example, it may be used a hydrate of such LiOH · H ₂ O, in this case, the content is a value obtained by converting the lithium hydroxide (LiOH) content.

  In the step (II), the slurry water (A) and the slurry water (B) obtained in the step (I) are mixed and cooled while purging with nitrogen to obtain a mixed slurry water (C). By mixing while purging with nitrogen, the dissolved oxygen concentration in the mixed slurry water (C) is reduced, effectively preventing the transition metal (M) compound from being oxidized and unnecessary by-products. The production of products can be prevented. Moreover, it can suppress effectively that the dispersion particle which exists in mixing slurry water (C) enlarges more than necessary by cooling.

  In mixing the slurry water (A) and the slurry water (B), the transition metal compound contained in the slurry water (A) is a transition metal ion with respect to 1 mol of lithium hydroxide contained in the slurry water (B). Is preferably an amount such that the total amount is 0.30 to 0.36 mol, more preferably 0.31 to 0.35 mol. More preferably, the amount is such that Further, in mixing the slurry water (A) and the slurry water (B), the transition metal compound contained in the slurry water (A) is 100 parts by mass of lithium hydroxide contained in the slurry water (B). The amount is preferably 69 to 83 parts by mass in terms of transition metal atom, more preferably 71 to 80 parts by mass, and 73 to 78 parts by mass. More preferably.

  Furthermore, in mixing the slurry water (A) and the slurry water (B), the phosphoric acid contained in the slurry water (A) is in an amount of 0.001 with respect to 1 mol of lithium hydroxide contained in the slurry water (B). The amount is preferably 28 to 0.38 mol, more preferably 0.30 to 0.36 mol, and more preferably 0.32 to 0.34 mol. More preferably. Moreover, when mixing slurry water (A) and slurry water (B), phosphoric acid contained in slurry water (A) is 115 with respect to 100 mass parts of lithium hydroxide contained in slurry water (B). The amount is preferably ˜155 parts by mass, more preferably 123 to 147 parts by mass, and even more preferably 131 to 139 parts by mass.

  The mixing order of the slurry water (A) and the slurry water (B) is not particularly limited, but it is preferable to add the slurry water (A) to the slurry water (B) from the viewpoint of the viscosity of the slurry.

  In the step (II), when mixing the slurry water (A) and the slurry water (B), it is preferable not to add an organic compound unless it is inevitably mixed. Examples of such organic compounds include surfactants such as dodecylbenzenesulfonate, saccharides, polyols, polyethers, organic acids, carbon blacks such as acetylene black and ketjen black, graphite, and amorphous carbon materials. It is mainly used for the purpose of controlling dispersed particles and the like and imparting conductivity at an early stage. That is, in the step (II), only the slurry water (A) and the slurry water (B) are mixed and cooled, and a high battery physical property is expressed without adding such an organic compound through the steps described later. The obtained lithium manganese phosphate positive electrode active material can be easily obtained.

In addition, you may add antioxidant other than an organic compound as needed. As such an antioxidant, sodium sulfite (Na ₂ SO ₃ ), hydrosulfite sodium (Na ₂ S ₂ O ₄ ), aqueous ammonia and the like can be used. From the viewpoint of preventing the generation of the lithium manganese phosphate positive electrode active material from being excessively added, the antioxidant is preferably added in an amount of 0.1 to 1 mol of the transition metal (M) compound. It is 01-1 mol, More preferably, it is 0.03-0.5 mol.

  The pressure in the step (II) is preferably 0.1 to 0.2 MPa, more preferably 0.1 to 0.15 MPa. Further, the time required for the step (II) is preferably 5 to 60 minutes, more preferably 15 to 45 minutes. Furthermore, the mixing (stirring) speed in the step (II) is preferably 250 to 600 rpm, more preferably 350 to 500 rpm. The dissolved oxygen concentration in the mixed slurry water (C) is preferably 0.5 mg / L or less, and more preferably 0.2 mg / L or less.

  In the step (II), the mixed slurry water (C) can be cooled depending on the transition metal (M) compound and the content thereof and the content thereof, but the temperature of the mixed slurry water (C) is mixed. It is preferable to cool the slurry water (C) to a temperature not higher than the boiling point. Thereby, the unnecessary influence received by the heat_generation | fever by reaction can be reduced effectively, and the lithium manganese phosphate positive electrode active material which can express a high battery physical property can be obtained. Specifically, the mixed slurry water (C) is preferably cooled to 90 ° C. or less, more preferably 20 to 70 ° C.

  The mixed slurry water (C) is finally adjusted to pH 4 to 8, and preferably adjusted to pH 5 to 7.5. Thereby, the growth of by-products and particles can be effectively suppressed. Under the present circumstances, you may use pH adjusters, such as sodium hydroxide and a sulfuric acid, as needed.

  In the step (III), the mixed slurry water (C) obtained in the above step (II) is subjected to a hydrothermal reaction and then pulverized. The mixed slurry water (C) is a thing obtained by using the slurry water (A) and the slurry water (B), and therefore contains a large amount of a transition metal compound and lithium hydroxide, and is subjected to a hydrothermal reaction. By subjecting to pulverization, a lithium manganese phosphate positive electrode active material capable of expressing high battery properties can be easily obtained.

  The amount of water used for the hydrothermal reaction is contained in the mixed slurry water (C) from the viewpoints of the solubility of the transition metal (M) compound, the ease of stirring, the efficiency of synthesis, and the like. Preferably it is 10-30 mol with respect to 1 mol of phosphate ions, More preferably, it is 12.5-25 mol.

  In subjecting the mixed slurry water (C) to a hydrothermal reaction, it is preferable to use a steam heating autoclave from the viewpoint of effectively preventing oxidation of the transition metal (M) compound. When the saturated steam is introduced into the autoclave and heating is started, it is preferable to further reduce the oxygen remaining in the autoclave by performing an operation to push out (replace) the air in the autoclave with the saturated steam.

  The reaction temperature in hydrothermal reaction should just be 100 degreeC or more, Preferably it is 130-250 degreeC, More preferably, it is 140-230 degreeC. When using a steam-heated autoclave, it is only necessary to seal in the autoclave and heat with steam. When the reaction is performed at 130 to 250 ° C, the pressure is 0.3 to 1.5 MPa, and the reaction is performed at 140 to 230 ° C. When performing, it will be 0.4-1.0 MPa. The reaction time is preferably 10 minutes to 3 hours, more preferably 10 minutes to 1 hour.

  After completion of the hydrothermal reaction, the mixed slurry water (C) containing the produced lithium manganese phosphate compound is pulverized. By performing such treatment, the produced lithium manganese phosphate compound becomes finer particles, which greatly contributes to the improvement of battery physical properties by the obtained lithium manganese phosphate compound positive electrode active material.

  In order to perform such pulverization treatment, it is preferable to use a ball mill method, and examples thereof include a planetary ball mill method, a rotating ball mill method, and a vibration ball mill method, and the pulverization treatment is performed by an apparatus equipped with a container made of steel, stainless steel, nylon, or the like. It is a method of applying. Among these, it is preferable to use the planetary ball mill method from the viewpoint of effectively suppressing the aggregation of lithium manganese phosphate compound particles and from the viewpoint of effectively pulverizing the aggregated particles into fine particles. .

For example, as the ball, specifically, alumina sphere, natural silica, iron ball, zirconia ball or the like is used. Moreover, it is preferable that the usage-amount of a ball | bowl is 0.3-0.5 g / cm < ³ > with respect to a container capacity | capacitance.

  Moreover, when performing a grinding | pulverization process, you may add a carbon material from a viewpoint which carries carbon on the obtained lithium manganese phosphate positive electrode active material, and raises the electroconductivity. Examples of the carbon material include organic solvents such as glucose, fructose, polyethylene glycol, polyvinyl alcohol, carboxymethylcellulose, saccharose, starch, dextrin, and citric acid; and carbon blacks such as acetylene black and ketjen black. The amount of the carbon material added is preferably 5 to 15 parts by mass, more preferably 8 to 13 parts by mass as the amount of carbon atom contained in the carbon source with respect to 100 parts by mass of the mixed slurry water (C). is there.

  The rotation speed of the ball mill during the pulverization treatment is preferably 100 to 450 rpm, more preferably 300 to 450 rpm. Moreover, the time which performs a grinding | pulverization process becomes like this. Preferably it is 1 to 20 hours, More preferably, it is 5 to 15 hours.

  The slurry water subjected to the pulverization treatment is dried after filtration. Before drying, it is desirable to distill off water or an optional carbon material using an evaporator or the like in advance. As the drying means, freeze drying or vacuum drying is used. Next, the firing is performed under an inert gas atmosphere or a reducing condition at 400 ° C. or higher, preferably 400 to 800 ° C. for 10 minutes to 3 hours, preferably 0.5 to 1.5 hours. preferable. In this way, a lithium manganese phosphate positive electrode active material extremely useful as a positive electrode material for a lithium ion battery can be obtained.

The obtained lithium manganese phosphate positive electrode active material can be used as a positive electrode active material for a lithium ion battery, and contains at least manganese (Mn) as a transition metal (M). Specifically, for example, it is represented by the following formula (A).
Li Fe _a Mn _1-a PO ₄ (A)
(In the formula, a represents a number satisfying 0 ≦ a <0.5.)
A in the formula (A) is preferably 0.05 to 0.4, more preferably 0.075 to 0.35, from the viewpoint of obtaining a lithium manganese phosphate compound having higher battery properties. More preferably, it is 0.1-0.3.

  The average particle size of the lithium manganese phosphate positive electrode active material is preferably 10 to 100 nm, and more preferably 10 to 50 nm.

Next, a lithium ion battery containing the obtained lithium manganese phosphate positive electrode active material as a positive electrode material will be described.
The lithium ion battery to which the positive electrode material of the present invention can be applied is not particularly limited as long as it has a positive electrode, a negative electrode, an electrolytic solution, and a separator as essential components.

  Here, as long as lithium ions can be occluded at the time of charging and released at the time of discharging, the material structure is not particularly limited, and a known material structure can be used. For example, a carbon material such as lithium metal, graphite, or amorphous carbon. It is preferable to use an electrode formed of an intercalating material capable of electrochemically inserting and extracting lithium, 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. For example, carbonates, halogenated hydrocarbons, ethers, ketones, nitriles, lactones An oxolane compound or the like can be used.

The type of the supporting salt is not particularly limited, but an inorganic salt selected from LiPF ₆ , LiBF ₄ , LiClO ₄ and LiAsF ₆ , a derivative of the inorganic salt, LiSO ₃ CF ₃ , 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 ), and organic salt derivatives It is preferable that it is at least 1 sort of.

  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.

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

[Example 1]
<< Preparation of slurry water (A) and slurry water (B) >>
H ₃ PO ₄ 5.09kg, was obtained _{FeSO 4 · 7H 2 O 1.63kg,} MnSO 4 · 5H 2 O5.60kg, and water 5.85kg were mixed slurry water (A). Further, 4.91 kg of LiOH.H ₂ O and 5.85 kg of water were mixed to obtain slurry water (B).

<< Manufacture of lithium manganese phosphate cathode active material >>
Next, the obtained slurry water (A) and slurry water (B) were mixed and stirred at a speed of 400 rpm for 30 minutes while purging nitrogen and mixed slurry water adjusted to a dissolved oxygen concentration of 0.5 mg / L. (C) was obtained. The pH of the mixed slurry water (C) was 6.8 and contained 1 mol of FeSO ₄ and MnSO ₄ in total with respect to 1 mol of phosphoric acid.

Next, the mixed slurry water (C) was put into a synthesis vessel installed in a steam heating autoclave. The inside of the autoclave was heated at 170 ° C. for 1 hour using saturated steam obtained by heating water with a dissolved oxygen concentration of less than 0.5 mg / L using a membrane separator. During the heating, stirring of the mixed slurry in the container was continued. The pressure in the autoclave was 0.8 MPa. The formed crystals were filtered and then washed with water. The washed crystal was vacuum dried at 60 ° C. and 1 Torr. 10 g of the obtained powder and 2.7 g of glucose were mixed and put into a container provided in a planetary ball mill (P-5, manufactured by Fritsch). Added.
Subsequently, 100 g of ZrO ₂ balls having a spherical diameter (100 μm) were used and pulverized for 10 hours at a rotational speed of 400 rpm. The obtained slurry was filtered, the solvent was distilled off using an evaporator, and then fired at 700 ° C. for 1 hr in a reducing atmosphere to obtain a lithium manganese phosphate positive electrode active material.
The average particle diameter of the obtained lithium manganese phosphate positive electrode active material _{(Li Fe 0.15 Mn 0.85 PO 4} ) was 40 nm.

<Manufacture of lithium ion batteries>
Next, the obtained lithium manganese phosphate positive electrode active material, ketjen black (conductive agent), and polyvinylidene fluoride (binding agent) were mixed at a mixing ratio of 75: 20: 5, and this was mixed with N-methyl. -2-Pyrrolidone was added and sufficiently kneaded 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 lithium ion battery was constructed using the positive electrode. A lithium foil punched to φ15 mm was used for the negative electrode. As the electrolytic solution, a solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / l in a mixed solvent in which ethylene carbonate and ethyl methyl carbonate were mixed at a volume ratio of 1: 1 was used. As the separator, a known one such as a polymer porous film such as polypropylene was used. These battery components were assembled and housed in a conventional manner in an atmosphere having a dew point of −50 ° C. or lower to produce a coin-type lithium ion battery (CR-2032).

A charge / discharge test at a constant current density was performed using the manufactured lithium ion battery. The charging conditions at this time were constant current charging with a current of 0.1 CA (17 mAg) and a voltage of 4.5 V, and the discharging conditions were constant current discharging with a current of 0.1 CA and a final voltage of 2.0 V. All temperatures were 30 ° C.
Then, the weight energy density (Wh / kg) was calculated based on the values of the discharge capacity and the average discharge voltage.
The results are shown in Table 1.

[Comparative Example 1]
A lithium manganese phosphate positive electrode active material was obtained in the same manner as in Example except that 4.37 kg of Li ₂ CO ₃ was used instead of 4.91 kg of LiOH.H ₂ O as the Li source.
Subsequently, using the obtained lithium manganese phosphate positive electrode active material, a coin-type lithium ion battery (CR-2032) was produced in the same manner as in Example 1, and a charge / discharge test was performed to determine the weight energy density (Wh / kg). Was calculated.
The results are shown in Table 1.

Claims (11)

Slurry water (A) containing a transition metal compound containing at least a manganese compound and phosphoric acid in an amount exceeding the solubility in water (A), and slurry water (B) containing lithium hydroxide in an amount exceeding the solubility in water Preparing step (I),
The obtained slurry water (A) and the slurry water (B) are mixed and cooled while purging with nitrogen to obtain a mixed slurry water (C) (II), and the obtained mixed slurry water (C) is hydrothermally heated. Step (III) of subjecting to pulverization after reaction
The manufacturing method of a lithium manganese phosphate positive electrode active material containing this.   The method for producing a lithium manganese phosphate positive electrode active material according to claim 1, wherein an organic compound is not added except in the case where it is inevitably mixed in step (II).   The phosphoric acid according to claim 1 or 2, wherein the slurry water (A) contains a transition metal compound in an amount of 2.0 to 5.0 times based on the solubility of at least a transition metal compound containing a manganese compound in water. Manufacturing method of manganese lithium positive electrode active material.   The phosphoric acid according to any one of claims 1 to 3, wherein the slurry water (B) contains 1.5 to 3.5 times the amount of lithium hydroxide based on the solubility of lithium hydroxide in water. Manufacturing method of manganese lithium positive electrode active material.   The method for producing a lithium manganese phosphate positive electrode active material according to any one of claims 1 to 4, wherein in step (II), the dissolved oxygen concentration in the mixed slurry water (C) is adjusted to 0.5 mg / L or less. .   The lithium manganese phosphate positive electrode active material according to any one of claims 1 to 5, wherein in the step (II), the mixed slurry water (C) is cooled to a temperature not higher than the boiling point of the mixed slurry water (C). Manufacturing method.   The method for producing a lithium manganese phosphate positive electrode active material according to any one of claims 1 to 6, wherein in the step (III), the time for performing the pulverization treatment is 5 to 15 hours.   The manufacturing method of the lithium manganese phosphate positive electrode active material of any one of Claims 1-7 in which a transition metal compound contains a manganese compound and an iron compound.   The method for producing a lithium manganese phosphate positive electrode active material according to claim 8, wherein the molar ratio of the manganese compound to the iron compound is more than 100: 0 and not more than 51:49.   The lithium manganese phosphate positive electrode active material obtained by the manufacturing method of any one of Claims 1-9.   A lithium ion battery containing the lithium manganese phosphate positive electrode active material according to claim 10 as a positive electrode material.