JP6568700B2 - Hydrogen manganate and lithium manganate and methods for producing them - Google Patents

Description

  The present invention relates to hydrogen manganate and lithium manganate, and methods for producing them. Specifically, the present invention relates to hydrogen manganate that can selectively recover lithium, lithium manganate that functions as an intermediate of the hydrogen manganate, and a method for producing the same.

  Lithium is indispensable as a secondary battery material for mobile phones and personal computers, and its use has permeated daily life. Until now, evaporation and drying methods and ore dissolution methods have been processed as lithium production methods. However, both methods still have problems such as an increase in cost due to a decrease in water quality or elution of heavy metal ions. On the other hand, a selective lithium recovery method from seawater and brine using an inorganic oxide as an adsorbent has recently attracted attention. Compared to the previous two processes, lithium can be recovered from water resources that exist anywhere, so it is overwhelmingly superior in terms of economy and environmental harmony.

However, seawater and brine contain high concentrations of sodium ions and other elements similar to lithium. Therefore, in the adsorption method, it is essential to have a lithium adsorbent that exhibits extremely high selectivity for lithium ions and can capture only lithium.
As the lithium adsorbent, a spinel phase or pseudo spinel phase manganese oxide ion sieve adsorbent is used. When a manganese oxide-based lithium adsorbent is immersed in seawater or brine, an ion exchange reaction between protons and lithium ions proceeds, and lithium is adsorbed on the lithium adsorbent. Thereafter, when the lithium adsorbent is put into an acid solution, an ion exchange reaction between protons and lithium ions proceeds, and lithium is desorbed from the acid solution. By repeating this adsorption / desorption cycle, lithium contained in seawater and brine can be concentrated and recovered.

Hydrogen manganate H _1.6 Mn _1.6 O ₄ is known as a lithium adsorbent exhibiting high adsorption performance in a manganese oxide system. The lithium adsorbent hydrogen manganate H _1.6 Mn _1.6 O ₄ can be obtained by baking and acid-treating lithium manganate LiMnO ₂ (Patent Document 1, Non-Patent Documents 1 and 2).
In order to produce high performance lithium adsorbent hydrogen manganate H _1.6 Mn _1.6 O ₄ , it is necessary to produce crystals of lithium manganate LiMnO ₂ as an intermediate with high purity and high quality. It is well known that there is. Conventionally, as a synthesis method of lithium manganate LiMnO ₂ , solid phase synthesis method using γ-MnOOH and LiOH.H ₂ O or LiCl, hydrothermal method using hydrothermal reaction of γ-MnOOH and LiOH solution, and γ-MnOOH as a solute The flux method etc. which were used for this are known (nonpatent literatures 1-3).
However, lithium manganate H _1.6 Mn _1.6 O _{4 which} is a lithium adsorbent having LiMnO ₂ as an intermediate produced by a conventional method has a small particle size, lacks chemical stability, and industrial productivity. It was scarce.

JP 2001-157838 A

R. Chitrakar, H.C. Kanoh, Y.M. Miyai, and K. Ooi, Chem. Mater. 12, 3151 (2000). Shu-Ying Sun, Jia-Li Xiao, Jin Wang, Xingfu Song, and Jian-Guo Yu, Ind. Eng. Chem. Res. 2014, 53, 15517-15521. T.A. Tang, H.H. Kanoh, and K.K. Ooi, J.A. Solid State Chem. 142, 19 (1999).

  The present invention relates to hydrogen manganate having a large particle size, excellent chemical stability, excellent lithium adsorptivity, and high productivity, lithium manganate as a precursor of the hydrogen manganate, and methods for producing these The purpose is to provide.

As a result of various studies on the growth of lithium manganate crystals, the present inventors succeeded in producing lithium manganate LiMnO ₂ having a size of several tens of micrometers by using the flux method. When firing the lithium manganate, the first time found that dozens of micrometers sized lithium manganate _Li x _Mn y _{O 4} crystal (0 <x <2,2 ≦ x + y ≦ 4) is produced. Further, by treating this lithium manganate Li _x Mn _y O ₄ (0 <x <2, 2 ≦ x + y ≦ 4) with an acid treatment, hydrogen manganate H _x Mn _{y which} is a macroporous structure lithium manganese oxide adsorbent O ₄ (0 <x <2, 2 ≦ x + y ≦ 4) was obtained. Li _x Mn _y O ₄ crystal (0 <x <2, 2 ≦ x + y ≦ 4) and Li _x Mn _y O ₄ (0 <x <2, 2 ≦ x + y ≦ 4) both have a spinel structure or a pseudo spinel structure. Show.
The present invention includes a high crystallinity of the lithium manganate _Li x _Mn y _{O 4,} lithium adsorbent serving manganate hydrogen _H x _Mn y _O 4, which can be produced using this (0 <x <2,2 ≦ x + y ≦ 4 ).

That is, hydrogen manganate according to the present invention is hydrogen manganate having a composition of H _x Mn _y O ₄ , and in the X-ray diffraction pattern, with respect to the intensity of the diffraction line corresponding to the {004} crystal plane, {111} intensity of the diffraction line corresponding to the crystal plane is 20 times or less 7 times or more, the lithium manganate have desorbed Li having a composition of Li _x Mn _y O _4, a plurality of petaloid surface is bent A porous body having a plurality of voids partitioned by a partition wall is formed. However, 0 <x <2, 2 ≦ x + y ≦ 4.
A diffraction line corresponding to the {111} crystal plane is a diffraction line existing in the range of 18 to 19 °, and a diffraction line corresponding to the {004} crystal plane is a diffraction line existing in the range of 44 to 45 °. is there. Both diffraction peaks are attributed to the spinel structure or pseudo-spinel structure.
The hydrogen manganate according to the present invention has a crystal structure as described above, has a large particle size and forms a porous body, and therefore has a large surface area, excellent exchangeability between protons and lithium ions, and excellent lithium adsorption characteristics. Have Moreover, since the size is as large as several tens of micrometers, the elution amount of Mn is small and it is chemically stable.

The elimination of Li can be performed by acid treatment.
In addition, the hydrogen manganate often forms a porous body having a plurality of voids partitioned by a plurality of petal-like partition walls whose surfaces are bent, thereby further increasing the surface area. Since the wall is thin, it excels in exchange of protons and lithium ions, and has excellent lithium adsorption characteristics.
In the hydrogen manganate H _x Mn _y O ₄ , 1 ≦ x <2 is preferable, and an excellent porous structure can be obtained.
In the hydrogen manganate H _x Mn _y O ₄ , if x = 1.6 and y = 1.6, the lithium adsorption characteristics are further improved.

The method for producing hydrogen manganate according to the present invention includes the following steps 1) and 2).
1): The following a~d _step, have a composition of _{Li x Mn y O 4 (0} <x <2,2 ≦ x + y ≦ 4), the X-ray diffraction pattern, corresponding to the {004} crystal faces A step of generating lithium manganate in which the intensity of the diffraction line corresponding to the {111} crystal plane is 7 to 20 times the intensity of the diffraction line .
a: mixing a Li source, a Mn source composed of MnO, and a flux component composed of at least one of a Cl-based alkali metal salt and an alkaline earth metal salt;
b: a step of heating the mixture in step a at 900 to 1100 ° C. to melt the flux component;
c: the flux component by cooling the molten mixture to form crystals, to obtain washed flux component, the removal to the LiMnO ₂ crystals step,
d: a step of further firing the crystal obtained in the step c at 350 to 450 ° C. ,
2): a step of further acid-treating lithium manganate crystals having a composition of Li _x Mn _y O ₄ (0 <x <2, 2 ≦ x + y ≦ 4) obtained in the step 1).

The Mn source in the mixture is preferably 5 mol% or less .
Before SL flux component, it is possible to use one or more of KCl, NaCl and LiCl.
The lithium manganate may have a composition of Li _1.6 Mn _1.6 O ₄ .

The lithium manganate according to the present invention is Li _x Mn _y O _Four A lithium manganate having a composition of (0 <x <2, 2 ≦ x + y ≦ 4) and having a spinel structure or a pseudo-spinel structure, and a diffraction corresponding to a {004} crystal plane in an X-ray diffraction pattern The intensity of the diffraction line corresponding to the {111} crystal plane is 7 to 20 times the intensity of the line.
A diffraction line corresponding to the {111} crystal plane is a diffraction line existing in the range of 18 to 19 °, and a diffraction line corresponding to the {004} crystal plane is a diffraction line existing in the range of 44 to 45 °. is there.
The lithium manganate is Li _1.6 Mn _1.6 O _Four Can have the following composition:

According to the present invention, a macroporous body having a plurality of voids partitioned by a plurality of petal-shaped partition walls whose surfaces are bent has a very large surface area, and the thickness of each partition wall is thin. Therefore, it is possible to provide hydrogen manganate that excels in exchange of protons and lithium ions and, as a result, easily penetrates seawater and brine into the interior and is suitable for high-speed lithium adsorption. In addition, lithium manganate that can be used as an intermediate for obtaining hydrogen manganate can be provided.

2 is an X-ray diffraction pattern of lithium manganate and hydrogen manganate obtained in Examples 1 and 2 and Comparative Examples 1 and 2. FIG. It is a SEM image (scanning electron microscope image) of hydrogen manganate obtained in Example 2 and Comparative Example 2. It is a graph which shows the relationship between the reaction time (holding time) in a flux growth process, and the intensity ratio of the intensity of the diffraction line corresponding to the {111} crystal plane with respect to the intensity of the diffraction line corresponding to the {004} crystal plane. 4 is a graph showing the elution amount of Mn from hydrogen manganate obtained in Example 2 and Comparative Example 2. 4 is a graph showing lithium adsorption capacities of hydrogen manganate obtained in Example 2 and Comparative Example 2.

Hereinafter, lithium manganate Li _x Mn _y O ₄ (0 <x <2, 2 ≦ x + y ≦ 4) having a particle size of several tens of micrometers and high chemical stability obtained in the present embodiment, and manganese The oxyhydrogen H _x Mn _y O ₄ will be described together with its production method.
As described above, the lithium manganate Li _x Mn _y O _{4 according} to the present embodiment has an {111} crystal plane corresponding to the intensity of the diffraction line corresponding to the {004} crystal plane in the X-ray diffraction pattern. The intensity of the corresponding diffraction line is about 3 times or more (preferably 5 times or more, more preferably 7 times or more) (Example 1 in FIG. 1). However, 0 <x <2, 2 ≦ x + y ≦ 4.
In FIG. 1, diffraction lines existing in the range of 18 to 19 ° correspond to the {111} crystal plane, and diffraction lines existing in the range of 44 to 45 ° correspond to the {004} crystal plane. It is a diffraction line.
The present lithium manganate has a spinel structure or a pseudo-spinel structure. Spinel is a kind of mineral and is represented by the general formula AB ₂ O ₄ (A = Li, Na, Mg, Ca, etc .; B = Mn, Al, Fe, etc.). The A site is 4-coordinated, while the B site is 6-coordinated. Even the same element can occupy both sites. In some cases, it is not occupied and may exist as a defective site. Therefore, in the composition formula of lithium manganate, the value of x + y can take a wide value from 2 to 4 as a pseudo spinel structure.

In addition, as shown in FIG. 2A, the hydrogen manganate H _x Mn _y O ₄ in the present embodiment has a plurality of voids whose surface is partitioned by a plurality of bent petal-shaped partition walls. It is characterized by forming a porous body. Further, as shown in FIG. 2 (a), the size is several tens of micrometers. Further, the partition wall is thin.

In the present embodiment, a method for producing lithium manganate having a composition of Li _x Mn _y O ₄ includes at least one of a Li source, a Mn source composed of MnO, and a Cl-based alkali metal salt and alkaline earth metal salt. A step of mixing a flux component comprising: heating the mixture to melt the flux component; cooling the mixture in which the flux component is melted to produce crystals; washing and removing the flux component to produce crystals; And a step of further firing the crystal obtained in the above step.

In the present embodiment, the hydrogen manganate having the composition of H _x Mn _y O ₄ is further subjected to an acid treatment on the crystal of lithium manganate having the composition of Li _x Mn _y O ₄ obtained in the above step. Can be obtained.

Next, the manufacturing method will be described in detail.
<Raw materials>
Commercially available manganese oxide (MnO) can be suitably used as the Mn raw material. Even if the surface or solid changes to hydroxide, it can be used. Other than manganese oxide is not preferable.
Li salt such as LiOH or LiCl can be used as the Li raw material.
In addition, alkali metal and alkaline earth metal chloride salts such as NaCl, KCl, and LiCl can be suitably used as the flux. These can be used alone or in combination.

<Flux training process>
First, a flux source composed of at least one of a Li source, a Mn source composed of MnO, and a Cl-based alkali metal salt and alkaline earth metal salt is mixed. The concentration of MnO is preferably 5 mol% or less, particularly 2 mol% or less, and more preferably about 1 to 0.1 mol%.
Subsequently, the said mixture is heated and a flux component is fuse | melted. The heating temperature of this mixture should just carry out crystal growth in the temperature range of 900-1100 degreeC. Preferably, the range of 900-1000 degreeC is more preferable, The temperature range of 950-1000 degreeC is more preferable. The reaction time (holding time) is not particularly limited because it is affected by the holding temperature, but it may be 5 minutes or more, preferably 5 hours or more at the treatment temperature.

Next, the components are crystallized by cooling for a predetermined time. After crystallization, the LiMnO ₂ crystal can be obtained by washing with warm water to remove the flux component.
By using 5 mol% or less of MnO as the Mn source and performing crystal growth at a heating temperature in the temperature range of 900 to 1100 ° C., a highly pure LiMnO ₂ crystal can be obtained.

Next, the LiMnO ₂ crystal is subjected to baking treatment at 350 to 450 ° C. for several hours in an oxidizing atmosphere, whereby the lithium manganate Li _x Mn _y O ₄ crystal in the present embodiment can be obtained. The lithium manganate Li _x Mn _y O ₄ obtained in this way has a size of several tens of micrometers, and as described above, in the X-ray diffraction pattern, the {004} crystal plane Is 3 times or more (preferably 5 times or more, more preferably 7 times or more).

The intensity ratio of the diffraction line corresponding to the {111} crystal plane to the intensity of the diffraction line corresponding to the {004} crystal plane in the X-ray diffraction pattern of the lithium manganate Li _x Mn _y O ₄ is the flux described above. It depends on the reaction time (holding time) in the growth process. The longer the reaction time (retention time), the greater the intensity ratio of the diffraction lines. FIG. 3 is a graph showing an example of the reaction time (retention time) and the intensity ratio of the diffraction lines (reaction temperature: retention temperature is 1000 ° C.).
As shown in FIG. 3, the intensity ratio of the diffraction lines increases linearly as the reaction time increases. The intensity ratio of the diffraction lines can be increased to several tens by setting the reaction time to several tens of hours. As described above, the intensity ratio of the diffraction lines is preferably 3 times or more (preferably 5 times or more, more preferably 7 times or more). The upper limit of the intensity ratio of the diffraction lines is not particularly limited, but about 15 to 20 times is appropriate from the relationship with the reaction time (retention time).

Then, by treating the lithium manganate Li _x Mn _y O ₄ having a crystal structure in which the specific crystal plane {111} is developed more than the other crystal plane {004}, as described above, Manganese having a composition of H _x Mn _y O ₄ having a size of several tens of micrometers and a surface having a porous body having a plurality of voids defined by a plurality of bent petal-like partition walls Oxyhydrogen is obtained. The hydrogen manganate according to the present embodiment has an extremely large surface area with a porous surface, and because the partition walls are thin, the proton and lithium ion exchangeability is excellent and excellent. Has lithium adsorption properties. Moreover, since the size is as large as several tens of micrometers, the elution amount of Mn is small and it is chemically stable.

Hereinafter, the present invention will be described in detail based on examples.
[Example 1]
1.18 g of MnO powder (Wako Pure Chemical Industries), 2.75 g of LiCl (Wako Pure Chemical Industries), and 7.08 g of KCl (Wako Pure Chemical Industries) were dry mixed in an alumina mortar for 15 minutes. . The sample was sealed in a 20 cm ³ alumina crucible and held at 1000 ° C. for 10 hours. The heating rate and cooling rate are 900 ° C./hour and 200 ° C./hour, respectively. Then washed with hot water to remove the flux component, to obtain crystals of LiMnO ₂ by drying. This crystal was further fired in air at 400 ° C. for 20 hours to obtain a pseudo-spinel type crystal of lithium manganate Li _1.6 Mn _1.6 O ₄ . The X-ray diffraction pattern of the lithium manganate crystal of Example 1 is shown in FIG.

[Example 2]
In order to prepare a lithium adsorbent, the lithium manganate Li _1.6 Mn _1.6 O ₄ crystal obtained in Example 1 was immersed in 0.5 mol / L hydrochloric acid for 15 hours, and then washed with distilled water. By drying, pseudo spinel crystals of hydrogen manganate H _1.6 Mn _1.6 O ₄ were obtained. FIG. 2A shows an SEM image of the obtained hydrogen manganate. A characteristic particle form, that is, a form in which the surface has a plurality of voids partitioned by a plurality of bent petal-like partition walls is shown.
In order to examine the chemical stability, it was immersed in 0.1 mol / L hydrochloric acid for 15 hours, and the amount of Mn eluted was analyzed by ICP emission analysis (high frequency inductively coupled plasma emission analysis). The analysis results are shown in FIG. The X-ray diffraction pattern of the hydrogen manganate crystal of Example 2 is shown in FIG.
The lithium ion adsorption test was conducted using conditions that imitate brine, that is, using an aqueous solution having a Li ion concentration of 1000 ppm and a Na ion concentration of 5000 ppm. The pH of the aqueous solution is approximately 9. 100 mg of the adsorbent was immersed in 10 ml of the aqueous solution for 20 hours. The adsorbed solution before and after the reaction was analyzed by ICP emission spectrometry. The Li ion adsorption amount was calculated from the difference in Li ion concentration of the aqueous solution before and after adsorption.

[Example 3]
Same as Example 1 except that the holding time was 0 hour (cooled immediately after the temperature was raised).
[Example 4]
Same as Example 1 except that the holding time was 2 hours.
The intensity ratio of the diffraction line corresponding to the {111} crystal plane to the intensity of the diffraction line corresponding to the {004} crystal plane in Example 1, Example 3, and Example 4 is shown in the graph of FIG.
The intensity ratio in Example 1 was 7.2, the intensity ratio in Example 3 was 3.8, and the intensity ratio in Example 4 was 4.5. As shown in FIG. 3, these increase linearly as the holding time increases.

[Comparative Example 1]
In order to clarify the effect of the flux method, lithium manganate was synthesized as a comparative example using a conventional hydrothermal method.
That is, using MnOOH as a Mn source, adding 20 times the chemical equivalent amount of LiCl, treating at 140 ° C. for 24 hours, washing and drying the precipitate to synthesize LiMnO ₂ crystals, It was calcined for a period of time and converted into lithium manganate Li _1.6 Mn _1.6 O ₄ crystals of Comparative Example 1. The X-ray diffraction pattern of the lithium manganate crystal of Comparative Example 1 is shown in FIG.

[Comparative Example 2]
The lithium manganate Li _1.6 Mn _1.6 O ₄ crystal obtained in Comparative Example 1 was immersed in 0.5 mol / L hydrochloric acid for 15 hours, then washed with distilled water and dried to give hydrogen manganate H _1.6 Mn _1.6 O ₄ crystals were obtained. FIG. 2B shows an SEM image of the obtained hydrogen manganate. When the hydrothermal synthesis method is used, the obtained particle form is an aggregate of fine particles of about 100 nanometers, and the surface as seen in Example 2 has a plurality of bent petal shapes. A structure having a plurality of gaps partitioned by a partition wall was not obtained.
In order to examine the chemical stability, it was immersed in 0.1 mol / L hydrochloric acid for 15 hours, and the amount of Mn eluted was analyzed by ICP emission spectrometry. The analysis results are shown in FIG. The X-ray diffraction pattern of the hydrogen manganate crystal of Example 2 is shown in FIG.
In the same manner as in Example 2, an adsorption test for Li ions was performed. In the same manner as in Example 2, the test was performed using an aqueous solution imitating brine and having an Li ion concentration of 1000 ppm and an Na ion concentration of 5000 ppm. The pH of the aqueous solution is approximately 9. The analysis of the aqueous solution used ICP emission analysis in the same manner as in Example 2.

<Crystal structure of lithium manganate>
As shown in FIG. 1, the lithium manganate of Example 1 has an X-ray diffraction pattern with respect to the intensity of a diffraction line corresponding to the {004} crystal plane (peak value existing in a range of 44 to 45 °). Thus, the intensity of the diffraction line corresponding to the {111} crystal plane (peak value existing in the range of 18 to 19 °) is about 7 times. That is, it has an orientation characteristic that the {111} crystal plane is well developed compared to the {004} crystal plane.
Since it has such a crystal structure, it is considered that when converted to hydrogen manganate of Example 2, it is converted to hydrogen manganate having a characteristic form shown in FIG. That is, the hydrogen manganate has a size of several tens of micrometers, and the surface forms a porous body having a plurality of voids partitioned by a plurality of bent petal-like partition walls.

  On the other hand, the lithium manganate of Comparative Example 1 has {111} against the intensity of the diffraction line corresponding to the {004} crystal plane (peak value existing in the range of 44 to 45 °) in the X-ray diffraction pattern. The intensity of the diffraction line corresponding to the crystal plane (peak value existing in the range of 18 to 19 °) is slightly less than three times. Even if this lithium manganate of Comparative Example 1 is converted to hydrogen manganate, as shown in FIG. 2 (b), it does not become a specific form of hydrogen manganate like the hydrogen manganate of Example 1.

<Elution of Mn in hydrogen manganate: Chemical stability>
As FIG. 4 shows, the Mn elution amount of the hydrogen manganate of the comparative example 2 produced using the conventional hydrothermal method is 4.3 wt%, and lacks chemical stability.
On the other hand, the Mn elution amount of hydrogen manganate of Example 2 produced using the flux method is 1.3 wt%, and the elution amount is suppressed, which is 3 times or more that of Comparative Example 2. It was found to have chemical stability.

<Lithium adsorption performance>
FIG. 5 shows lithium adsorption characteristics of hydrogen manganate of Example 2 and hydrogen manganate of Comparative Example 2. The lithium adsorption amount of hydrogen manganate obtained by the hydrothermal method of Comparative Example 2 was 41.0 mg _Li · g ⁻¹ . This result is in good agreement with the conventional hydrogen manganate result. On the other hand, the lithium adsorption amount of hydrogen manganate in Example 2 was 55.4 mg. It became clear that the lithium adsorption performance of hydrogen manganate obtained by using the flux method shows slightly higher activity than the adsorbent obtained by the hydrothermal method.

In addition, a claim preliminary group is added as follows.
(Appendix 1)
Manganese hydrogenate having a composition of H _x Mn _y O ₄ , wherein the surface forms a porous body having a plurality of voids partitioned by a plurality of bent petal-like partition walls Oxyhydrogen.
However, 0 <x <2, 2 ≦ x + y ≦ 4.
(Appendix 2)
The hydrogen manganate according to appendix 1, obtained by acid treatment of lithium manganate having a composition of Li _x Mn _y O ₄ .
(Appendix 3)
In the X-ray diffraction pattern, the lithium manganate having the composition of Li _x Mn _y O ₄ has a diffraction line intensity corresponding to the {111} crystal plane relative to a diffraction line intensity corresponding to the {004} crystal plane. The hydrogen manganate according to appendix 2, characterized in that the lithium manganate is 3 times or more.
(Appendix 4)
The peak of the diffraction line in which the peak value of the diffraction line that exists in the range of 18 to 19 ° in the lithium manganate having the composition of Li _x Mn _y O ₄ exists in the range of 44 to 45 ° in the X-ray diffraction pattern. The hydrogen manganate according to supplement 2, wherein the hydrogen manganate is 3 times or more the value.
(Appendix 5)
The hydrogen manganate according to any one of supplementary notes 1 to 4, having a composition of H _1.6 Mn _1.6 O ₄ .

At present, lithium ion recovery from seawater and brine using adsorbents uses low manganic acid crystals with a low chemical stability of about 100 nanometers, whereas the method of the present invention provides a chemical stability of 3 It becomes possible to use a manganic acid crystal having a size of several tens of micrometers improved by a factor of two or more.
According to the present invention, it is found for the first time that lithium manganate Li _x Mn _y O ₄ can be obtained in a single phase by using the flux method, and by treating this with an acid, the particle size is increased and the lithium absorption capacity is increased. It has become possible to provide excellent hydrogen manganate H _x Mn _y O ₄ . Compared to conventional crystal growth methods, the particle size can be increased by about two orders of magnitude.
Currently, it is easy to synthesize industrially in large quantities, and it can be said to be a preferable method from the viewpoint of simplification of the production process and reduction of energy consumption.

Claims (9)

In the X-ray diffraction pattern, the intensity of the diffraction line corresponding to the {111} crystal plane is 7 to 20 times the intensity of the diffraction line corresponding to the {004} crystal plane. _x Mn _y O _Four Lithium manganate having the composition: However, 0 <x <2, 2 ≦ x + y ≦ 4. A diffraction line corresponding to the {111} crystal plane is present in a range of 18 to 19 °, and a diffraction line corresponding to the {004} crystal plane is present in a range of 44 to 45 °. The lithium manganate according to claim 1, wherein H _x Mn _y O _Four The lithium manganate according to claim 1 or 2, wherein the lithium manganate has a Li composition, and a plurality of voids partitioned by a plurality of petal-shaped partition walls having a bent surface. A hydrogen manganate characterized by forming a porous body. However, 0 <x <2, 2 ≦ x + y ≦ 4. 4. The hydrogen manganate according to claim 3 , wherein 1 ≦ x <2 in the hydrogen manganate H _x Mn _y O ₄ . In the manganate hydrogen _{H x Mn y O 4, x} = 1.6, manganese hydrogen according to claim 4, characterized in that the y = 1.6. A method for producing hydrogen manganate according to any one of claims 3 to 5, comprising the following steps 1) and 2).
1): The following steps a to _d have a composition of Li _x Mny O ₄ , and in the X-ray diffraction pattern, {111} crystals with respect to the intensity of the diffraction line corresponding to the {004} crystal plane A step of generating lithium manganate having a diffraction line intensity corresponding to the surface of 7 to 20 times.
However, 0 <x <2, 2 ≦ x + y ≦ 4.
a: mixing a Li source, a Mn source composed of MnO, and a flux component composed of at least one of a Cl-based alkali metal salt and an alkaline earth metal salt;
b: a step of heating the mixture in step a at 900 to 1100 ° C. to melt the flux component;
c: a step of cooling the mixture in which the flux component is melted to form crystals, and washing and removing the flux components to obtain LiMnO ₂ crystals;
d: a step of further firing the crystal obtained in the step c at 350 to 450 ° C.,
2): A step of further acid-treating lithium manganate crystals having the composition of Li _x Mn _y O ₄ obtained in the step 1).   The method for producing hydrogen manganate according to claim 6, wherein the Mn source in the mixture is 5 mol% or less.   The method for producing hydrogen manganate according to claim 6 or 7, wherein the flux component is at least one of KCl, NaCl, and LiCl. The method for producing hydrogen manganate according to any one of claims 6 to 8, wherein the lithium manganate is lithium manganate having a composition of Li _1.6 Mn _1.6 O ₄ .