JP2013230966A - Metal-substituted trimanganese tetraoxide and method for producing the same, and method for producing lithium manganese complex oxide using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal-substituted trimanganese tetraoxide which is capable of providing a metal-substituted lithium manganese complex oxide that serves as an excellent positive electrode material for lithium secondary batteries, and a method for producing the metal-substituted trimanganese tetraoxide.SOLUTION: A metal-substituted trimanganese tetraoxide is represented by general formula: AMnO(A is a metal element other than Mn, and x<1) and has a particle diameter of ≥1 μm. The metal-substituted trimanganese tetraoxide can be obtained by a production method which comprises a crystallization step wherein the metal-substituted trimanganese tetraoxide is crystallized, without passing through a metal-substituted manganese hydroxide, from an aqueous manganese salt solution that contains manganese ions and metal ions other than manganese ions.

Description

  The present invention relates to a metal-substituted manganese oxide, a method for producing the metal-substituted manganese oxide, and a method for producing a lithium manganese composite oxide using the metal-substituted manganese oxide.

Manganese oxide (MnO _x ) is used as a raw material for a lithium manganese composite oxide used as a positive electrode material of a lithium secondary battery. In order to obtain a positive electrode material for a lithium secondary battery with higher battery performance, a so-called metal-substituted lithium manganese composite oxide in which a part of manganese is substituted with another metal has been reported.

  As a method for producing such a metal-substituted lithium manganese composite oxide, in addition to a lithium raw material and a manganese raw material, a method of adding and mixing and firing other elemental compounds (Patent Document 1), finely pulverizing each raw material A method for firing an aggregate obtained by drying a slurry of the slurry (Patent Document 2) has been reported.

  In addition, a method for obtaining manganese oxide containing calcium or magnesium by obtaining manganese hydroxide containing these from an aqueous solution to which calcium or magnesium has been added during the synthesis of manganese oxide and oxidizing it has been reported. (Patent Document 3).

JP 2001-307724 A JP-A-11-171551 JP 2000-128540 A

  Patent document 1 and patent document 2 were the manufacturing methods of the lithium manganese complex oxide which each mixes a raw material. In such a manufacturing method, it was difficult to uniformly mix the raw materials. Furthermore, the obtained lithium manganese composite oxide depends on the mixing degree of the raw materials, and its battery characteristics are likely to vary.

  In the production method of Patent Document 3, the particle size distribution is uniform, but only small particles can be obtained. Therefore, the operability is difficult. Furthermore, in this production method, when the added amount of calcium or the like exceeds 2.50 mol%, impurities are mixed, and a uniform manganese raw material for lithium manganese composite oxide cannot be obtained. The lithium manganese composite oxide obtained from such a low uniformity manganese raw material has low battery characteristics.

  An object of the present invention is to provide a metal-substituted lithium trimanganese tetraoxide and a method for producing the same, which can obtain a metal-substituted lithium manganese composite oxide excellent as a positive electrode material for a lithium secondary battery. It is another object of the present invention to provide a method for producing a metal-substituted lithium manganese composite oxide using such metal-substituted manganese trioxide.

  The inventors of the present invention have made extensive studies on manganese oxides used as raw materials for metal-substituted lithium manganese composite oxides. As a result, the present inventors have found that metal-substituted manganese trioxide having a controlled particle size is particularly suitable as a raw material for lithium manganese composite oxide.

  Furthermore, such a metal-substituted manganese trioxide does not pass through a metal-substituted manganese hydroxide crystal from a metal-containing manganese salt aqueous solution, or a condition that sufficiently suppresses the crystal growth of the metal-substituted manganese hydroxide. It was found that it can be obtained by direct oxidation below.

  Hereinafter, the metal-substituted manganese trioxide of the present invention will be described.

  The present invention is a metal-substituted manganese trioxide, which is a manganese oxide represented by the following formula (1).

A _x Mn _3-x O ₄ (1)

  In the metal-substituted trimanganese tetraoxide of the present invention, x in formula (1) is 1 or less. When x exceeds 1, Mn is reduced too much, and the electric capacity of the metal-substituted lithium manganese composite oxide obtained using this as a raw material becomes too low. X in Formula (1) is preferably 0.5 or less, and more preferably 0.35 or less. On the other hand, when x in the formula (1) is 0.01 or more, and further 0.2 or more, the effect of the substitution element is easily obtained.

  In the formula (1), A is a metal element other than manganese (Mn), preferably a metal other than Mn and lithium (Li), magnesium (Mg), aluminum (Al), silica (Si), calcium (Ca), titanium (Ti), vanadium (V), chromium (Cr), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge), zirconium More preferably, it is at least one selected from the group consisting of (Zr), molybdenum (Mo), silver (Ag), indium (In), and tin (Sn). By containing these metal elements, the battery characteristics of the metal-substituted lithium manganese composite oxide obtained using the metal-substituted manganese trioxide of the present invention as a raw material are easily improved. From the viewpoint of improving charge / discharge cycle characteristics and battery characteristics at high temperatures when a metal-substituted lithium manganese composite oxide is produced, it is more preferable that A is at least one of Mg and Al.

  The crystal structure of the metal-substituted manganese trioxide of the present invention is preferably a spinel structure. This crystal structure is the same as that of the JCPDS pattern No. An X-ray diffraction pattern of 24-734 and a similar X-ray diffraction pattern are shown.

  The particle diameter of the metal-substituted manganese trioxide of the present invention is 1 μm or more. By substantially not including fine particles of less than 1 μm, the mixing with the lithium compound is improved and the operability during use is enhanced.

  The average particle diameter is preferably 1 μm or more, and more preferably 3 μm or more. When the average particle diameter is 1 μm or more, the storage stability of the metal-substituted titanium manganese composite oxide obtained using this as a raw material tends to be high. When the average particle size is 30 μm or less, and further 10 μm or less, it becomes easy to use as a raw material for metal-substituted lithium manganese composite oxide.

  In the present invention, the average particle diameter is a particle diameter (so-called D50) that is 50% on a volume basis. When the particle size distribution of the composite particles is monodispersed, the mode particle size and the average particle size match. In this case, the mode particle size can be used as the average particle size.

  The metal-substituted manganese trioxide of the present invention preferably has a standard deviation coefficient of variation (hereinafter referred to as “Cv”) of 50% or less, more preferably 45% or less, and more preferably 30% or less. More preferably it is. When Cv is 50% or less, the particle diameter becomes uniform. Thereby, reaction of the metal substituted manganese tetraoxide of this invention and a lithium raw material progresses more uniformly.

  Cv can be obtained by the following equation (2).

          Cv (%) = (standard deviation of particle diameter ÷ average particle diameter) × 100

The metal-substituted manganese trioxide of the present invention preferably has a BET specific surface area of 6.5 m ² / g or less, and preferably 5 m ² / g or less. When the BET specific surface area is 6.5 m ² / g or less, the metal-substituted manganese trioxide of the present invention has a high filling property, and the reactivity with the lithium compound tends to be uniform.

The filling property of the metal-substituted manganese trioxide of the present invention is preferably high. However, the filling properties of the metal-substituted manganese trioxide of the present invention vary depending on the metal species to be substituted and the amount thereof. It can be illustrated that the tap density of the metal-substituted manganese trioxide of the present invention is 1.0 g / cm ³ or more, and further 1.1 g / cm ³ or more.

  Next, the manufacturing method of the metal substituted manganese trioxide of this invention is demonstrated.

  The metal-substituted manganese trioxide of the present invention does not pass through a metal-substituted manganese hydroxide from a manganese salt aqueous solution containing manganese ions and metal ions other than manganese (hereinafter referred to as “metal-containing manganese salt aqueous solution”). It can be obtained by a production method having a crystallization step of crystallizing metal-substituted manganese trioxide.

  In the above step, that is, the step of crystallizing metal-substituted manganese trioxide from the metal-containing manganese salt aqueous solution without going through the metal-substituted manganese hydroxide, the metal-substituted manganese hydroxide aqueous solution contains the metal-substituted manganese hydroxide aqueous solution. Metal-substituted manganese trioxide is produced without precipitating crystals in the alkaline region.

  Therefore, the method for producing a metal-substituted manganese tetroxide according to the present invention includes a manganese hydroxide or a metal-substituted manganese hydroxide (hereinafter referred to as “manganese hydroxide” collectively in an alkaline region from a metal-containing manganese salt aqueous solution. The metal-substituted manganese trioxide is produced without going through the step of oxidizing the manganese hydroxide with an oxidizing agent.

  In the method for producing metal-substituted manganese trioxide of the present invention, the crystal phase of manganese hydroxide is not generated at all in the crystallization step, and after the hydroxide microcrystals are precipitated for a short time, Is converted to metal-substituted manganese trioxide before growing into hexagonal plate-like crystals. That is, the method for producing metal-substituted manganese trioxide of the present invention is characterized in that hexagonal plate-like manganese hydroxide crystals are not produced in the crystallization step. By not producing manganese hydroxide crystals, it is possible to obtain metal-substituted manganese trioxide with a reasonably low surface area and high filling properties.

  Whether or not a hexagonal plate-like manganese hydroxide crystal has occurred can be determined by observing the particle shape of the obtained metal-substituted manganese trioxide.

  In the production method of the present invention, the pH of the metal-containing manganese salt aqueous solution when crystallizing the metal-substituted manganese trioxide or the pH of the slurry containing the crystallized metal-substituted manganese tetraoxide is generated by manganese hydroxide. It is preferable that the pH is difficult to adjust, and it is more preferable to set the pH from weakly acidic to weakly alkaline.

  Specifically, the pH is preferably 6 or more and 9 or less, and more preferably pH 6.5 or more and pH 8.5 or less. Further, it is more preferable that the central value of pH is within this range. By making the pH of the metal-containing manganese salt aqueous solution or slurry within this range, it becomes difficult to produce manganese hydroxide.

  The pH of the metal-containing manganese salt aqueous solution or slurry is preferably in the above range during the crystallization step. It is preferable to reduce the variation in pH of the metal-containing manganese salt aqueous solution or slurry during the crystallization process. Specifically, the pH is maintained in the range of the center value ± 0.5, more preferably in the range of the center value ± 0.3, and still more preferably in the range of the center value ± 0.1.

  In the production method of the present invention, in the crystallization step, the oxidation-reduction potential (hereinafter also simply referred to as “oxidation-reduction potential”) of the metal-containing manganese salt aqueous solution with respect to the standard hydrogen electrode is preferably 0 mV or more and 300 mV or less, and 30 mV As mentioned above, it is more preferable to set it as 150 mV or less. By making the oxidation-reduction potential of the metal-containing manganese salt aqueous solution within this range, it becomes difficult to produce manganese hydroxide. Furthermore, by setting the oxidation-reduction potential of the metal-containing manganese salt aqueous solution to 300 mV or less, γ-MnOOH having a needle-like particle form is hardly generated as a by-product, and the filling property of the resulting metal-substituted manganese trioxide is higher. Prone.

  The oxidation-reduction potential of the metal-containing manganese salt aqueous solution or slurry in the crystallization step is preferably within the above-mentioned range during the crystallization step. Furthermore, it is preferable to reduce the variation in redox potential of the metal-containing manganese salt aqueous solution or slurry during the crystallization step. Specifically, the oxidation-reduction potential is preferably maintained in the range of the central value ± 50 mV, more preferably the central value ± 30 mV, and still more preferably the central value ± 20 mV.

  In the crystallization step, crystallization is performed with the pH, oxidation-reduction potential, or both in the above range, and the fluctuation range of the pH, oxidation-reduction potential, or both is reduced, so that the metal substitution with a uniform particle diameter can be achieved. Manganese trioxide can be obtained. The metal-substituted manganese trioxide obtained in this way has a high filling property, and easily reacts uniformly with the lithium compound.

  The metal-containing manganese salt aqueous solution used in the production method of the present invention contains manganese ions and metal ions other than manganese.

  Metal ions other than manganese ions (hereinafter referred to as “A ions”) include Mg, Al, Si, Ca, Ti, V, Cr, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, and Nb. , Mo, Ag, In and Sn are preferably at least one ion selected from the group. By containing these metal ions, the battery characteristics of the metal-substituted lithium manganese composite oxide using the metal-substituted manganese trioxide obtained by the production method of the present invention as a raw material can be easily improved. From the viewpoint of improving charge / discharge cycle characteristics and battery characteristics at high temperatures when a metal-substituted lithium manganese composite oxide is produced, it is more preferable that the A ion is one or more ions of Mg or Al.

  Metal-containing manganese salt solutions include manganese and A sulfate, chloride, nitrate, and acetate aqueous solutions, and these metals and oxides into various acid aqueous solutions such as sulfuric acid, hydrochloric acid, nitric acid, and acetic acid. A dissolved one can be used.

  The metal-containing manganese salt aqueous solution can have an arbitrary concentration, but the total concentration of metal ions including manganese ions can be exemplified as 1 mol / L or more. By setting the total concentration of metal ions in the aqueous metal-containing manganese salt solution to 1 mol / L or more, metal-substituted manganese trioxide can be efficiently obtained.

  In the metal-containing manganese salt solution, the ratio of manganese ions to A ions can be set arbitrarily. For example, 0 <A / Mn ≦ 0.5 can be exemplified as the ratio of the molar concentration of A ions to the molar concentration of manganese ions (A / Mn (mol / mol)).

  When adjusting the pH of the metal-containing manganese salt aqueous solution, it is preferable to use an alkaline aqueous solution (hereinafter referred to as an alkaline aqueous solution). Although there is no restriction | limiting in the kind of alkaline aqueous solution, Aqueous solutions, such as sodium hydroxide and potassium hydroxide, can be illustrated.

  The concentration of the alkali metal or alkaline earth metal in the alkaline aqueous solution may be 1 mol / L or more.

  In the production method of the present invention, in the crystallization step, the temperature of the metal-containing manganese salt aqueous solution may be 60 ° C. or higher and 95 ° C. or lower, preferably 70 ° C. or higher and 80 ° C. or lower. By setting the temperature of the metal-containing manganese salt aqueous solution at the time of crystallization within this range, the particle size of the metal-substituted manganese trioxide is likely to be uniform.

  In the production method of the present invention, it is preferable to perform crystallization using an oxidizing agent in the crystallization step. Examples of the oxidizing agent include gas oxidizing agents such as oxygen-containing gas, and liquid oxidizing agents such as hydrogen peroxide. From the viewpoint of simplifying operability, the oxidizing agent is preferably a gaseous oxidizing agent, more preferably an oxygen-containing gas, and even more preferably air. Furthermore, it is more preferable to crystallize by blowing a gaseous oxidant into the metal-containing manganese salt aqueous solution. Thereby, the crystallization of the metal-substituted manganese trioxide is likely to occur more uniformly.

  In the production method of the present invention, it is preferable to mix a metal-containing manganese salt aqueous solution and an alkali aqueous solution in the crystallization step.

  The mixing method of the metal-containing manganese salt aqueous solution and the alkaline aqueous solution is not particularly limited as long as both can be uniformly mixed. Examples of the mixing method include a method in which an alkaline aqueous solution is added to a metal-containing manganese salt aqueous solution and mixing, a method in which a metal-containing manganese salt aqueous solution and an alkaline aqueous solution are added to a solvent such as pure water, and the like. From the viewpoint of sufficiently and uniformly reacting the metal-containing manganese salt aqueous solution and the alkali aqueous solution, the mixing method is preferably a method in which the metal-containing manganese salt aqueous solution and the alkali aqueous solution are added to a solvent and mixed.

  In the conventional manufacturing method, after producing manganese hydroxide under a nitrogen atmosphere, metal-substituted manganese trioxide is produced under an oxidizing atmosphere. Therefore, in the conventional production method, it is essential to change the reaction atmosphere, and metal-substituted manganese trioxide can not be produced continuously. In contrast, in the production method of the present invention, metal-substituted manganese trioxide is directly crystallized from a metal-containing manganese salt aqueous solution. Therefore, there is no need to change the reaction atmosphere during the process. Therefore, metal-substituted manganese trioxide can be continuously produced directly from the metal-containing manganese salt aqueous solution.

  In the production method of the present invention, it is preferable to perform crystallization without coexisting a complexing agent in the crystallization step. The complexing agent in this specification has the complexing ability similar to these besides ammonia, ammonium salt, hydrazine, and EDTA.

  These complexing agents affect the crystallization behavior of metal substituted manganese tetroxide. Therefore, the metal-substituted manganese trioxide obtained in the presence of a complexing agent has powder properties such as particle size even if the metal-substituted manganese trioxide obtained without using a complexing agent has the same composition. Is different.

  The method for producing metal-substituted manganese trioxide of the present invention may include a firing step of firing the obtained metal-substituted manganese trioxide and obtaining metal-substituted manganese trioxide.

(Method for producing lithium manganese composite oxide)
The method for producing a lithium manganese composite oxide of the present invention includes a mixing step of mixing the metal-substituted manganese trioxide described above and at least one of lithium and a lithium compound, and a heating step of heat treatment.

  The metal-substituted lithium manganese composite oxide preferably has a spinel crystal structure, and more preferably is represented by the following formula.

Li _{1 + y} A _z Mn _2-yz O ₄

  In the above formula, A is a metal element other than Mn, and y and z each satisfy the following formula.

0 ≦ y ≦ 0.33
0 ≦ z ≦ 0.67

  Any lithium compound may be used. Examples of the lithium compound include lithium hydroxide, lithium oxide, lithium carbonate, lithium iodide, lithium nitrate, lithium oxalate, and alkyl lithium. Examples of preferable lithium compounds include lithium hydroxide, lithium oxide, and lithium carbonate.

  The metal-substituted manganese trioxide of the present invention contains a metal uniformly and has a particle size excellent in operability. Furthermore, it has a uniform composition even if the amount of the substituted metal is as high as several mol%. Therefore, it is a positive electrode material for lithium secondary batteries, and as a raw material for producing lithium manganese composite oxide having high battery characteristics, more specifically as a raw material for producing metal-substituted lithium manganese composite oxide Can be used.

XRD patterns of Examples 1 to 4 and Comparative Example 1 (a) Example 1, b) Example 2, c) Example 3, d) Example 4, e) Example 5) Particle size distribution of Mg-substituted manganese trioxide of Example 2 Powder X-ray diffraction patterns of Examples 5 to 8 and Comparative Example 1 (h) Example 5, i) Example 6, j) Example 7, k) Example 8, e) Comparative Example 1) Particle size distribution of Mg substituted manganese trioxide of Example 8 Particle size distribution of Mg-containing trimanganese tetraoxide of Comparative Example 1 XRD patterns of Mg-substituted lithium manganese composite oxides of Examples 9 and 10 (a) Example 9 and b) Example 10)

  Next, although this invention is demonstrated with a specific Example, this invention is not limited to these Examples. Evaluation of each example and comparative example was performed as follows.

(Chemical composition analysis)
The sample was dissolved in a mixed aqueous solution of hydrochloric acid and hydrogen peroxide, and the contents of Na, Mg, Ca, Li, SO ₄ ²⁻ and Mn were determined by ICP method.

(X-ray diffraction measurement)
The crystal phase of the sample was measured by X-ray diffraction. The measurement was performed with a general X-ray diffractometer. A CuKα ray (λ = 1.5405 mm) is used as the radiation source, the measurement mode is step scan, the scan condition is 0.04 ° per second, the measurement time is 3 seconds, and the measurement range is 2 ° to 5 ° to 80 °. Measured with

(Average particle size)
The mode particle diameter was measured as the average particle diameter of the sample. MICROTRAC HRA 9320-X100 (trade name, Nikkiso Co., Ltd.) was used for the measurement of the mode particle size. Before the measurement, the sample was dispersed in pure water to obtain a measurement solution, and ammonia water was added to adjust the pH to 8.5. Thereafter, the measurement solution was subjected to ultrasonic dispersion for 3 minutes, and then the mode particle diameter was measured.

Example 1
Manganese sulfate (manufactured by Wako Pure Chemicals, reagent special grade) and magnesium sulfate (manufactured by Wako Pure Chemicals, reagent special grade) are dissolved in pure water and contain 1.98 mol / L manganese sulfate and 0.02 mol / L magnesium sulfate. A solution was obtained. The Mg / Mn molar ratio in the raw material solution was 0.01.

  The obtained raw material solution was added to 80 ° C. pure water, thereby obtaining a reaction slurry in which an oxide was crystallized. The addition of the raw material solution is performed by blowing oxygen gas into the pure water (reaction slurry) so that the oxidation-reduction potential in the pure water (reaction slurry) is 100 ± 20 mV, and the pH of the pure water (reaction slurry) is This was carried out while adding a 2 mol / L sodium hydroxide aqueous solution to pure water (reaction slurry) so as to be constant at 8.0.

  The obtained reaction slurry was filtered, washed with pure water, and then dried at 120 ° C. in the air to obtain the oxide of Example 1.

  The composition of the oxide of Example 1 was Mg / Mn molar ratio = 0.008. Further, the XRD diffraction pattern of the oxide of Example 1 is the JCPDS pattern No. The spinel structure has an X-ray diffraction pattern equivalent to the X-ray diffraction pattern of No. 24-734, but the peak shifts to the high angle side and the peak intensity ratio also changes. It turned out that it shifted to the X-ray diffraction pattern of 23-392.

From these results, it was found that the oxide of Example 1 was Mg-substituted manganese trioxide represented by the formula Mg _0.02 Mn _2.98 O ₄ .

  The evaluation results of the Mg-substituted manganese trioxide of Example 1 are shown in Table 1, and the XRD diffraction pattern is shown in FIG.

Example 2
The oxide of Example 2 was obtained in the same manner as in Example 1 except that an aqueous solution containing 1.9 mol / L manganese sulfate and 0.1 mol / L magnesium sulfate was used as the raw material solution. The Mg / Mn molar ratio in the raw material solution was 0.05.

  The composition of the oxide of Example 2 was Mg / Mn molar ratio = 0.045. Further, the XRD diffraction pattern of the oxide of Example 1 is the JCPDS pattern No. The spinel structure has an X-ray diffraction pattern equivalent to the X-ray diffraction pattern of No. 24-734, but the peak shifts to the high angle side and the peak intensity ratio also changes. It turned out that it shifted to the X-ray diffraction pattern of 23-392.

From these results, it was found that the oxide of Example 2 was Mg-substituted manganese trioxide represented by the formula Mg _0.13 Mn _2.87 O ₄ .

  The evaluation results of the Mg-containing manganese oxide of Example 2 are shown in Table 1, the XRD diffraction pattern is shown in FIG. 1, and the particle size distribution is shown in FIG.

Example 3
The oxide of Example 3 was obtained in the same manner as in Example 1 except that an aqueous solution containing 1.8 mol / L manganese sulfate and 0.2 mol / L magnesium sulfate was used as the raw material solution. The Mg / Mn molar ratio in the raw material solution was 0.11.

  The composition of the oxide of Example 3 was Mg / Mn molar ratio = 0.08. Further, the XRD diffraction pattern of the oxide of Example 1 is the JCPDS pattern No. The spinel structure has an X-ray diffraction pattern equivalent to the X-ray diffraction pattern of No. 24-734, but the peak shifts to the high angle side and the peak intensity ratio also changes. It turned out that it shifted to the X-ray diffraction pattern of 23-392.

From these results, it was found that the oxide of Example 3 was Mg-substituted manganese trioxide represented by the formula Mg _0.22 Mn _2.78 O ₄ .

  The evaluation results of the Mg-containing manganese oxide of Example 3 are shown in Table 1, and the XRD diffraction pattern is shown in FIG.

Example 4
The oxide of Example 3 was obtained in the same manner as in Example 1 except that an aqueous solution containing 1.75 mol / L manganese sulfate and 0.25 mol / L magnesium sulfate was used as the raw material solution. The Mg / Mn molar ratio in the raw material solution was 0.14.

  The composition of the oxide of Example 4 was Mg / Mn molar ratio = 0.45. Further, the XRD diffraction pattern of the oxide of Example 1 is the JCPDS pattern No. The spinel structure has an X-ray diffraction pattern equivalent to the X-ray diffraction pattern of No. 24-734, but the peak shifts to the high angle side and the peak intensity ratio also changes. It turned out that it shifted to the X-ray diffraction pattern of 23-392.

From these results, it was found that the oxide of Example 3 was Mg-substituted manganese trioxide represented by the formula Mg _0.35 Mn _2.65 O ₄ .

  The evaluation results of the Mg-containing manganese oxide of Example 4 are shown in Table 1, and the XRD diffraction pattern is shown in FIG.

  From the XRD diffraction patterns of Examples 1 to 4, it was found that the XRD diffraction peak shifts to the high angle side as the Mg content in the manganese oxide increases. Thus, it was found that these Mg-substituted manganese trioxides had Mg substituted in the spinel crystal structure of trimanganese tetraoxide.

Example 5
An aqueous solution containing 1.94 mol / L manganese sulfate and 0.06 mol / L magnesium sulfate was used as the raw material solution, and the reaction slurry was drained at the same rate as the addition rate of the raw material solution and continuously 100 The oxide of this example was obtained in the same manner as in Example 1 except that the reaction was performed for a period of time. The Mg / Mn molar ratio in the raw material solution was 0.03.

  The composition of the oxide of this example was Mg / Mn molar ratio = 0.02. Further, the XRD pattern of the oxide of this example is the JCPDS pattern No. The spinel structure of the XRD pattern is equivalent to the XRD pattern of 24-734, but the peak shifts to the high angle side, the peak intensity ratio also changes, and the JCPDS pattern No. It turned out that it shifted to the XRD pattern of 23-392.

From these results, it was found that the oxide of this example was Mg-substituted manganese trioxide represented by the formula Mg _0.07 Mn _2.93 O ₄ .

  The evaluation results of the Mg-containing manganese oxide of this example are shown in Table 1, and the XRD pattern is shown in FIG.

Example 6
The oxide of this example was obtained in the same manner as in Example 5 except that an aqueous solution containing 1.68 mol / L manganese sulfate and 0.32 mol / L magnesium sulfate was used as the raw material solution. The Mg / Mn molar ratio in the raw material solution was 0.16.

  The composition of the oxide of this example was Mg / Mn molar ratio = 0.03. Further, the XRD pattern of the oxide of this example is the JCPDS pattern No. The spinel structure of the XRD pattern is equivalent to the XRD pattern of 24-734, but the peak shifts to the high angle side, the peak intensity ratio also changes, and the JCPDS pattern No. It turned out that it shifted to the XRD pattern of 23-392.

From these results, it was found that the oxide of the additional example 2 was Mg-substituted manganese trioxide represented by the formula Mg _0.08 Mn _2.92 O ₄ .

  The evaluation results of the Mg-containing manganese oxide of this example are shown in Table 1, and the XRD pattern is shown in FIG.

Example 7
The oxide of this example was obtained in the same manner as in Example 5 except that an aqueous solution containing 1.86 mol / L manganese sulfate and 0.14 mol / L magnesium sulfate was used as the raw material solution. The Mg / Mn molar ratio in the raw material solution was 0.07.

  The composition of the oxide of this example was Mg / Mn molar ratio = 0.03. Further, the XRD pattern of the oxide of this example is the JCPDS pattern No. The spinel structure of the XRD pattern is equivalent to the XRD pattern of 24-734, but the peak shifts to the high angle side, the peak intensity ratio also changes, and the JCPDS pattern No. It turned out that it shifted to the XRD pattern of 23-392.

From these results, it was found that the oxide of this example was Mg-substituted manganese trioxide represented by the formula Mg _0.1 Mn _2.9 O ₄ .

  The evaluation results of the Mg-containing manganese oxide of this example are shown in Table 1, and the XRD pattern is shown in FIG.

Example 8
The oxide of this example was obtained in the same manner as in Example 5 except that an aqueous solution containing 1.68 mol / L manganese sulfate and 0.32 mol / L magnesium sulfate was used as the raw material solution. The Mg / Mn molar ratio in the raw material solution was 0.16.

  The composition of the oxide of this example was Mg / Mn molar ratio = 0.07. Further, the XRD pattern of the oxide of this example is the JCPDS pattern No. The spinel structure of the XRD pattern is equivalent to the XRD pattern of 24-734, but the peak shifts to the high angle side, the peak intensity ratio also changes, and the JCPDS pattern No. It turned out that it shifted to the XRD pattern of 23-392.

From these results, it was found that the oxide of this example was Mg-substituted manganese trioxide represented by the formula Mg _0.2 Mn _2.8 O ₄ .

  The evaluation results of the Mg-containing manganese oxide of this example are shown in Table 1, the XRD pattern is shown in FIG. 3, and the particle size distribution is shown in FIG.

  From the results of these Examples, it was confirmed that the metal-substituted manganese trioxide can be continuously produced over a long time of 100 hours or more by the production method of the present invention.

Comparative Example 1
A raw material solution was obtained in the same manner as in Example 2. The Mg / Mn molar ratio in the raw material solution was 0.05.

  The obtained raw material solution was added to pure water at 80 ° C., thereby generating a hydroxide to obtain a reaction slurry. The addition of the raw material solution was performed by blowing nitrogen gas into pure water (reaction slurry), and adding 2 mol / L sodium hydroxide aqueous solution to pure water (reaction slurry) so that the pH of the pure water (reaction slurry) was constant at 10. To the reaction slurry).

  After the hydroxide was generated, nitrogen gas blowing was stopped and air was blown into the reaction slurry to obtain a reaction slurry containing the oxide.

  The obtained reaction slurry was filtered, washed with pure water, and then dried at 120 ° C. in the air to obtain the oxide of Example 1.

  The composition of the oxide of Comparative Example 1 was Mg / Mn molar ratio = 0.001, and was an Mg-containing manganese oxide containing Mg.

  The XRD diffraction pattern of the Mg-containing manganese oxide of Comparative Example 1 is the JCPDS pattern No. In addition to the X-ray diffraction pattern of 24-734, an X-ray diffraction pattern of layered manganese oxide and the like was confirmed, and it was found to be composed of a mixture.

  The evaluation results of the Mg-containing manganese oxide of Comparative Example 1 are shown in Table 1, the XRD diffraction pattern is shown in FIG. 1, and the particle size distribution is shown in FIG.

[Lithium manganese complex oxide]
Example 9
The Mg-substituted manganese trioxide of Example 1 and lithium carbonate were mixed in a mortar and baked at 850 ° C. for 12 hours in an air stream. As a result, an Mg-substituted lithium manganese composite oxide having Li, Mg, and Mn was obtained.

The obtained Mg-substituted lithium manganese composite oxide had a single phase with a spinel structure and a composition of Li _1.10 Mg _0.09 Mn _1.81 O ₄ .

  The evaluation results of the Mg-substituted lithium manganese composite oxide of Example 9 are shown in Table 2, and the XRD diagram is shown in FIG.

Example 10
A Mg-substituted lithium manganese composite oxide having Li, Mg, and Mn was obtained in the same manner as in Example 9 except that the Mg-substituted manganese trioxide of Example 2 was used.

The obtained Mg-substituted lithium manganese composite oxide had a single phase with a spinel structure and a composition of Li _1.10 Mg _0.09 Mn _1.81 O ₄ .

  The evaluation results of the Mg-substituted lithium manganese composite oxide of Example 10 are shown in Table 2, and the XRD diagram is shown in FIG.

Claims (10)

Metal-substituted manganese trioxide represented by the general formula A _x Mn _3−x O ₄ (A is a metal element other than Mn, x <1), and the particle diameter is 1 μm or more.   A is at least one selected from the group consisting of Mg, Al, Si, Ca, Ti, V, Cr, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Nb, Mo, Ag, In, and Sn. The metal-substituted manganese trioxide according to claim 1, wherein   The metal-substituted manganese trioxide according to claim 1 or 2, wherein A is at least one of Al and Mg.   The metal-substituted manganese trioxide according to any one of claims 1 to 3, wherein the crystal structure is a spinel structure.   The metal-substituted manganese trioxide according to any one of claims 1 to 4, wherein the average particle size is 1 µm or more.   The metal-substituted manganese trioxide according to any one of claims 1 to 5, wherein the standard deviation coefficient of variation of the particle diameter is 50% or less.   It is a manufacturing method of the metal substituted manganese trioxide as described in any one of Claims 1 thru | or 6, Comprising: A metal substituted manganese hydroxide is passed from the manganese salt aqueous solution containing manganese ions and metal ions other than manganese. A method for producing metal-substituted manganese trioxide having a crystallization step of crystallizing metal-substituted manganese trioxide without crystallization.   8. The metal-substituted tetrasodium tetraoxide according to claim 7, wherein in the crystallization step, metal-substituted manganese trioxide is crystallized under a condition satisfying at least one of a pH of 6 to 9 and a redox potential of 0 mV to 300 mV. Manufacturing method of manganese oxide.   The method for producing metal-substituted manganese trioxide according to claim 7 or 8, wherein an oxygen-containing gas is blown into the manganese salt aqueous solution in the crystallization step.   A method for producing a lithium manganese composite oxide, comprising: a mixing step of mixing the metal-substituted manganese trioxide according to claim 1 and a lithium compound; and a heating step of heat treatment.

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