Magnesium composite oxide or calcium composite oxide, and method for producing same

Abstract

Provided are a novel magnesium composite oxide or calcium composite oxide, and a method for producing same.　The production method is for producing a composite oxide containing magnesium or calcium, and includes: a heating step for heating a precursor compound at a temperature of 500ºC or lower in the presence of a salt that contains magnesium or calcium; and a washing step for washing with a washing liquid that includes water after the heating step. A combination of the precursor compound and the composite oxide is any of (A) to (E).

Description

Magnesium composite oxide or calcium composite oxide, and method for producing the same

[0001] The present invention relates to a magnesium composite oxide or a calcium composite oxide, and a method for producing the same.

[0002] Magnesium secondary batteries have attracted attention as next-generation secondary batteries because they have a higher energy density than widely used lithium-ion batteries, and combine excellent safety with low cost. In magnesium secondary batteries, metallic Mg, which has a low standard electrode potential, is expected to be used as the negative electrode. However, for the positive electrode material of magnesium secondary batteries, it is necessary to select a material that exhibits excellent characteristics in terms of capacity and other factors from a large number of compound groups (e.g., Non-Patent Document 1, etc.).

[0003] Similarly, calcium batteries (also called calcium ion batteries or calcium secondary batteries) using calcium ions or calcium metals have also attracted attention as post-lithium ion secondary batteries. Calcium is the fifth most abundant element in the Earth's crust, is inexpensive, readily available, and widely distributed. Therefore, the practical application of calcium batteries is expected to reduce material procurement risks and product costs. Furthermore, metallic Ca combines a low redox potential with a high volumetric capacity, making it a promising element for use in next-generation battery devices from the perspective of energy density. Furthermore, calcium ions have a lower electron density than other polyvalent ions, which may favor their diffusion within electrolytes and electrodes. This has attracted attention from the perspectives of power density and charge / discharge speed. However, research and development of calcium batteries still faces various challenges in electrode materials, and the development of new positive electrode materials is particularly urgent.

[0004] As described above, battery materials (e.g., solid electrolytes, positive electrode materials, etc.) for use in secondary batteries using magnesium ions or calcium ions as carrier ions have not yet been established, and therefore there is a demand for the development of novel magnesium composite oxides or calcium composite oxides.

[0005] Journal of Electroceramics 2009, 22, 13-19.

[0006] The present invention has been made in view of the above-mentioned current state of the prior art, and a main object of the present invention is to provide a novel magnesium composite oxide or calcium composite oxide and a method for producing the same.

[0007] The present inventors have conducted extensive research to achieve the above-mentioned object. As a result, they have found that a novel magnesium composite oxide or calcium composite oxide and a method for producing the same can be provided by including a heating step in which a predetermined precursor compound is heated at a relatively low temperature in the presence of a salt containing magnesium or calcium, followed by a washing step. Based on this finding, the present inventors have conducted further research and have completed the present invention. That is, the present invention encompasses the following features.

[0008] Item 1. A method for producing a composite oxide containing magnesium or calcium, comprising: a heating step of heating a precursor compound at a temperature of 500°C or less in the presence of a salt containing magnesium or calcium; and a washing step of washing the precursor compound with a washing liquid containing a polar solvent after the heating step, wherein the combination of the precursor compound and the composite oxide is any one of the following (A) to (E): (A) The precursor compound is a compound represented by general formula (1A): A １ ａ１ M １ ｍ１ D ｄ O ６ (1A) [wherein, A １ is at least one selected from the group consisting of H, Li, Na, K, Ca, Mg, Ba, Sr, Pb, Cu, and Ag, and M １ is at least one selected from the group consisting of Mg, Ca, Ti, Si, Ge, Sn, Ni, Co, Cu, Al, Cr, Mn, Fe, Ga, and Zn, and D is at least one selected from the group consisting of Te, Sb, Bi, Ru, Nb, Ta, Sn, and W, and 0<a1≦6, 0<m1≦2, and 0<d≦1.], and the composite oxide is a compound represented by general formula (1A'): X ａ１／２ M１ ｍ１ D ｄ O ６ (1A') [wherein X is Mg or Ca, provided that X is the same as the A １ The other symbols are the same as above.]; (B) The precursor compound is a compound represented by the general formula (1B): A ２ ａ２ M ２ ｍ２ E ２ O ７-δ (1B) [wherein, A ２ is at least one selected from the group consisting of Li, Na, K, Rb, Cs, Ba, Sr, Pb, Cu, and Ag, and M ２ is at least one selected from the group consisting of Mg, Al, Ca, Fe, Ti, V, Ni, Cu, Mn, Co, and Zn, E is at least one selected from the group consisting of V, Si, Ge, P, and B, and 0<a2≦4, 0<m2≦2, and −1≦δ≦2.], and the composite oxide is a compound represented by the general formula (1B'): X ａ２／２ M ２ ｍ２ E ２ O ７-δ (1B') [wherein X is Mg or Ca, and X is the same as A ２ The other symbols are the same as above.]; (C) The precursor compound is a compound represented by the general formula (1C): A ３ ａ３ M ３ ｍ３ GO ４ (1C) [wherein, A ３ is at least one selected from the group consisting of Li, Na, K, Rb, Cs, Ca, Mg, Ba, Sr, Cu, and Ag, and M ３ is at least one selected from the group consisting of Mg, Al, Ca, Ni, Fe, Mn, Co, Cu, and Zn, G is at least one selected from the group consisting of Si, Ge, Ti, Sn, Mn, and Zr, and 0<a3≦2, 0<m3≦1.], and the composite oxide is a compound represented by the general formula (1C'): X ａ３／２ M ３ｍ３ GO ４ (1C') [wherein X is Mg or Ca, and X is the same as A ３ The other symbols are the same as above.]; (D) The precursor compound is a compound represented by the general formula (1D): A ４ ａ４ M ４ ｍ４ (G'O ４ ) ｇ (1D) [wherein, A ４ is at least one selected from the group consisting of Li, Na, K, Rb, Cs, Ba, Ca, Mg, Sr, Pb, Cu, and Ag, and M ４ is at least one selected from the group consisting of Mg, Al, Ca, Ni, Cu, Zn, Fe, Mn, V, and Ti, and G' is at least one selected from the group consisting of Si, Ge, P, S, and Zr, and 0<a4≦4, 0<m4≦2, and 2≦g≦6.], and the composite oxide is a compound represented by the general formula (1D'): X ａ４／２ M ４ ｍ４ (G'O ４ ) ｇ (1D') [wherein X is Mg or Ca, and X is the same as A ４ The other symbols are the same as above.]; (E) The precursor compound is a compound represented by the general formula (1E): A ５ ａ５ M ５ ｍ５ P.O. ４ B (1E) [wherein, A ５ is at least one selected from the group consisting of Li, Na, K, Rb, Cs, Ba, Ca, Mg, Sr, Pb, Cu, and Ag, and M ５ is at least one selected from the group consisting of Mg, Al, Ca, Ni, Cu, Zn, Fe, Mn, V, and Ti, and B is F, Cl, OH, and CO ３ and the composite oxide is at least one selected from the group consisting of: ａ５／２ M ５ｍ５ P.O. ４ B (1E') [wherein X is Mg or Ca, and X is the same as A ５ The other symbols are the same as above.]

[0009] Item 2. The production method according to Item 1, wherein the composite oxide is a compound obtained by substituting a cation constituting the precursor compound with a magnesium ion or a calcium ion constituting the salt.

[0010] Item 3. The method according to Item 1 or 2, wherein the composite oxide has an average particle size of 1 nm to 100 nm.

[0011] Item 4. The production method according to any one of Items 1 to 3, wherein the salt is a molten salt.

[0012] Item 5. The manufacturing method according to any one of Items 1 to 4, wherein the heating step is carried out under a pressure of less than 0.2 MPa.

[0013] Item 6. The method according to any one of Items 1 to 5, wherein the composite oxide is an electrode material, a solid electrolyte material, an optical material, or a magnetic material.

[0014] Section 7. XMGeO ４ , XM ２ Si ２ O ７ , X ２ MSi ２ O ７ , XM ２ B ２ O ７ , XMP ２ O ７ , XMV ２ O ７ , XMPO ４ F, XMTiO ４ , XMn ２ P ２ O ７ , XM ２ TeO ６ , XMSiO ４ , X １．５ M ２ SbO ６ , X １．５ M ２ Bio ６ , X１．５ M ２ RuO ６ , X ２ MTeO ６ , X ２ MSbO ６ , X １．５ Cu ２／５ Ni ２／５ Co ２／５ Fe ２／５ Mn ２／５ SbO ６ , X １．５ Cu １／３ Ni １／３ Co １／３ Mg １／３ Mn １／３ Cu １／３ SbO ６ , or X １．５ M １．５ TeO ６ [In each formula, X is Mg or Ca, and M is Fe, Mn, Mg, Ca, Co, Ni, Ni ０．５ Co ０．５ , Cu, or Zn.] The composite oxide represented by the formula:

[0015] Section 8. Na ２ Mg ２ TeO ６ Mg ３ TeO ６ Magnesium composite oxide represented by the formula:

[0016] Item 9. CaM having an ilmenite-type crystal structure ２ TeO ６ Calcium complex oxide represented by the formula:

[0017] Item 10. Na ４ MgTeO ６ , Na ４ CaTeO ６ , Na ３ Mg １．５ TeO ６ , Na ３ Zn １．５ TeO ６ , Na ３ Co ２ RuO ６ , Li ２ Zn ２ TeO ６ , Na３ Co １．５ TeO ６ , Na ３ Cu １．５ TeO ６ , Na ３ Mg ２ RuO ６ , Na ３ Co ２ Bio ６ , Na ３ NiCoBiO ６ , Na ３ Ca ２ SbO ６ or Na ３ NiCoSbO ６ A compound represented by the formula:

[0018] According to the method of the present invention, a novel magnesium composite oxide or calcium composite oxide and a method for producing the same can be provided.

[0019] Precursor compounds Li obtained in Production Examples 1 to 5 ４ MTeO ６ (M=Cu, Co, Zn, Mg, Ni) The XRD patterns of the precursor compounds Na obtained in Production Examples 6 to 11a are shown. ４ MTeO ６ (M=Zn, Mg, Co, Cu, Ni, Ca) XRD patterns of the precursor compounds Li obtained in Production Examples 12 to 16 are shown. ２ M ２ TeO ６ (M=Zn, Cu, Co, Mg, Ni) The XRD patterns of the precursor compounds Na obtained in Production Examples 17 to 21 are shown. ２ M ２ TeO ６ (M=Zn, Cu, Co, Mg, Ni) The XRD patterns of the precursor compounds Na obtained in Production Examples 23 to 27 are shown. ３ M １．５ TeO ６ (M=Zn, Mg, Cu, Co, Ni) The XRD patterns of the precursor compounds Na obtained in Production Examples 28 to 30 are shown. ３ M ２ RuO ６ The XRD patterns of the precursor compounds Na obtained in Production Examples 31 to 33 (M=Co, Mg, Ni) are shown. ３ M２ Bio ６ (M=Ni, Co, Ni ０．５ Co ０．５ The XRD patterns of the precursor compounds Na obtained in Production Examples 34 to 36a and 37 are shown. ３ M ２ SbO ６ (M=Ni, Co, Ni ０．５ Co ０．５ , Ca) are shown. ２ FeDO ４ (D = Si, Ti, Ge) and K ２ CaSiO ４ The XRD patterns of the precursor compounds K obtained in Production Examples 43 to 46 are shown. ２ MP ２ O ７ The XRD patterns of the magnesium composite oxides Mg obtained in Examples 1-1 to 1-5 (M=Cu, Ni, Co, Mn) are shown. ２ MTeO ６ The XRD patterns of the magnesium composite oxides Mg obtained in Examples 1-6 to 1-10 (M=Mg, Co, Ni, Zn, Cu) are shown. ２ MTeO ６ The XRD patterns of the magnesium composite oxides MgM (M = Mg, Co, Ni, Zn, Cu) obtained in Examples 1-11 to 1-15 are shown. ２ TeO ６ The XRD patterns of the magnesium composite oxides Mg obtained in Examples 1-16 to 1-18 (M=Cu, Zn, Mg, Co, Ni) are shown. １．５ M ２ Bio ６ (M=Ni, Co, Ni ０．５ Co ０．５ The XRD patterns of the precursor compounds Na obtained in Production Examples 17 to 21 are shown. ２ M ２ TeO ６ (Upper row; M = Zn, Cu, Co, Mg, Ni), magnesium composite oxides MgM obtained in Examples 1-11 to 1-15 ２ TeO ６ (middle), and the magnesium composite oxides MgM obtained in Comparative Examples 1 to 5 ２ TeO ６The color of the precursor compound Na obtained in Production Examples 6 to 10 is shown. ４ MTeO ６ (Upper row: M=Zn, Mg, Co, Cu, Ni) Magnesium composite oxides Mg obtained in Examples 1-6 to 1-10 ２ MTeO ６ (middle), and the magnesium composite oxides Mg obtained in Comparative Examples 6 to 10 ２ MTeO ６ The color of the magnesium composite oxide (Mg) is shown in the lower part. ３ TeO ６ Specifically, (a) and (d) show the polymorphism of the vacant Mg crystal structure (polyhedral model and atomic model) obtained in Example 1-14. ３ TeO ６ (b) and (e) show the novel crystal structure of the corundum-type Mg obtained in Examples 1-4. ３ TeO ６ (c) and (f) show the crystal structure of the ilmenite-type Mg obtained in Example 1-9. ３ TeO ６ The crystal structures of the magnesium composite oxides Mg obtained in Examples 1-9, 1-14, and 1-4 are shown in order from the top. ３ TeO ６ The XRD patterns of the magnesium composite oxides MgNi obtained in Comparative Example 1 and Example 1-11 are shown in order from the top. ２ TeO ６ The XRD patterns of the magnesium composite oxides MgCo obtained in Comparative Example 2 and Examples 1-12 are shown in order from the top. ２ TeO ６ The XRD patterns of the magnesium composite oxides MgZn obtained in Comparative Example 5 and Examples 1-10 are shown in order from the top. ２ TeO ６ The XRD patterns of the magnesium composite oxides MgCu obtained in Comparative Example 3 and Example 1-13 are shown in order from the top. ２ TeO ６ The XRD patterns of the magnesium composite oxides Mg obtained in Comparative Example 7 and Examples 1-7 are shown in order from the top. ２ CoTeO ６The XRD patterns of the magnesium composite oxides Mg obtained in Comparative Example 6 and Examples 1-6 are shown in order from the top. ２ NiTeO ６ The XRD pattern of the known Mg ２＋ Conductor and the ilmenite-type Mg obtained in Examples 1-9 ３ TeO ６ The results of plotting the ionic conductivity of the magnesium composite oxides MgM obtained by the solid phase synthesis method in Comparative Examples 1 to 5 are shown. ２ TeO ６ The XRD patterns of the magnesium composite oxides Mg obtained by the solid phase synthesis method in Comparative Examples 6 to 10 are shown. ２ MTeO ６ The XRD patterns of the calcium composite oxides Ca obtained in Examples 2-1 to 2-5 (M=Cu, Zn, Mg, Co, Ni) are shown. ２ MTeO ６ (M=Mg, Co, Ni, Zn, Cu, Ca) and Ca ３．５ SbO ６ The XRD patterns of the calcium composite oxides CaM obtained in Examples 2-6 to 2-10 are shown. ２ TeO ６ The XRD patterns of the calcium composite oxides Ca obtained in Examples 2-11 to 2-13 (M=Cu, Zn, Mg, Co, Ni) are shown. １．５ M ２ RuO ６ The XRD patterns of the calcium composite oxides Ca (M = Ni, Co, Mg) obtained in Examples 2-14 to 2-16 are shown. １．５ M ２ Bio ６ (M=Ni, Co, Ni ０．５ Co ０．５ The XRD patterns before and after the calcination are shown. １．５ M ２ SbO ６ (M=Ni, Co, Ni ０．５ Co ０．５ Calcium composite oxides CaFeDO obtained in Examples 2-20 to 2-23 are shown. ４ (D=Si, Ti, Ge) and Ca ２ SiO４ The XRD patterns of the precursor compounds Na obtained in Production Examples 17 to 21 are shown. ２ M ２ TeO ６ (Upper row; M = Zn, Cu, Co, Mg, Ni), and calcium composite oxides CaM obtained in Examples 2-6 to 2-10 ２ TeO ６ The color of the precursor compound Na obtained in Production Examples 34 to 36 is shown. ３ M ２ SbO ６ (Top row: M = Ni, Co, Ni ０．５ Co ０．５ ), and calcium composite oxides Ca obtained in Examples 2-17 to 2-19 １．５ M ２ SbO ６ The colors in the lower row indicate the polymorphism of the crystal structure (polyhedron model) of calcium complex oxide. Specifically, (a) shows CaM ２ TeO ６ (M=Mg, Co, Ni, Zn; Examples 2-6 to 2-10, etc.), and (b) shows Ca １．５ M １．５ TeO ６ (c) shows Ca ２ MTeO ６ (Examples 2-1 to 2-5, etc.), and (d) shows Ca ３．５ DO ６ (D = Sb, Bi; Example 2-21, etc.) and Ca ３ TeO ６ (Example 2-20, etc.), (e) shows Ca ｘ M ２ TeO ６ (f) shows a new crystal structure of Ca ｘ M ２ Bio ６ (x<1.0) and Ca ｘ M ２ SbO ６ The new crystal structure of K (x<1.0) is shown. ２ NiP ２ O ７ , and the calcium composite oxide CaNiP obtained in Example 2-26 ２ O ７The XRD pattern of the magnesium composite oxide Mg obtained in Example 3-1 is shown. ３ TeO ６ The upper part of the figure shows the XRD pattern of the precursor compound Na. The lower part shows the XRD pattern calculated by simulation. ４ MgTeO ６ (Left) and magnesium composite oxide Mg ３ TeO ６ The crystal structure of the magnesium composite oxide Mg obtained in Examples 4-1 to 4-6 is shown on the right. １．５ M ２ RuO ６ (M = Co, Mg, Ni) and Mg １．５ M ２ SbO ６ (M=Ni, Co, Ni ０．５ Co ０．５ The XRD patterns of the magnesium composite oxides Mg obtained in Examples 4-7 to 4-9 are shown. １．５ M ２ Bio ６ (M=Ni, Co, Ni ０．５ Co ０．５ 5-1 (top) and 5-2 (middle). ２ MgTeO ６ The lower part shows the XRD pattern of the perovskite-type Ca ２ MgTeO ６ The XRD pattern of the calcium composite oxide CaMgSiO obtained in Example 6-1 is shown. ４ The XRD pattern of CaMgSiO with a kirschsteinite-type olivine framework structure calculated by simulation is shown (top). ４ The XRD patterns of the calcium composite oxides Ca obtained in Examples 7-1 to 7-4 are shown. １．５ M ２ SbO ６ (M=Ni, Co, Ni ０．５ Co ０．５ , Ni １／６ Co １／６ Zn １／６ Mg １／６ Cu １／６ Mn１／６ The XRD patterns of the calcium composite oxides Ca obtained in Examples 7-5 and 7-6 are shown. １．５ M ２ RuO ６ (M=Ni, Mg) The XRD patterns of the calcium composite oxides Ca obtained in Examples 7-7 and 7-8 are shown. １．５ M ２ TeO ６ The XRD patterns of the calcium composite oxides Ca obtained in Examples 7-9 to 7-14 (M=Zn, Mg) are shown. ２ MTeO ６ (M=Co, Cu, Ni, Ca, Fe, Mn) XRD patterns are shown.

[0020] In this specification, the expressions "contain" and "comprise" include any of "contain," "comprise," "consist only of," "consist essentially only of," and "consist only of."

[0021] In this specification, the expression "A to B" indicating a range of values ​​means "greater than or equal to A and less than or equal to B."

[0022] 1. Method for Producing a Composite Oxide Containing Magnesium or Calcium The production method of the present invention comprises a heating step of heating a predetermined precursor compound described below in the presence of a salt containing magnesium or calcium at a temperature of 500°C or less, and a subsequent washing step.

[0023] The production method of the present invention, having the above-mentioned features, can provide a novel magnesium composite oxide or calcium composite oxide and a production method thereof. Alternatively, the production method of the present invention can provide a material that could previously only be obtained under harsh synthesis conditions of high pressure and high temperature, inexpensively and simply, using mild conditions.

[0024] According to the production method of the present invention, a composite oxide having a crystal structure corresponding to the crystal structure of the precursor compound as a raw material can be easily obtained. In this case, the production method of the present invention can provide a variety of composite oxides by appropriately selecting the raw materials.

[0025] Another advantage of the production method of the present invention is that the low temperature conditions of metathesis synthesis make it easy to obtain nanoparticles immediately after nucleation and before significant crystal growth occurs. This is in contrast to conventional solid-state synthesis, where the high reaction temperatures tend to lead to large particle sizes due to Ostwald ripening and particle coarsening during crystal growth.

[0026] The present invention will be described in detail below.

[0027] 1-1. Precursor Compound The precursor compound used in the present invention is any one of the following (1A), (1B), (1C), (1D), and (1E) depending on the combination (A) to (E) of the precursor compound and the target composite oxide.

[0028] (A) The precursor compound according to the first aspect is represented by the general formula (1A): １ ａ１ M １ ｍ１ D ｄ O ６ (1A) [wherein, A １ is at least one selected from the group consisting of H, Li, Na, K, Ca, Mg, Ba, Sr, Pb, Cu, and Ag, and M １ is at least one selected from the group consisting of Mg, Ca, Ti, Si, Ge, Sn, Ni, Co, Cu, Al, Cr, Mn, Fe, Ga, and Zn, and D is at least one selected from the group consisting of Te, Sb, Bi, Ru, Nb, Ta, Sn, and W, and 0<a1≦6, 0<m1≦3, and 0<d≦1.] The composite oxide obtained in this case is a compound represented by the following general formula (1A′).

[0029] In general formula (1A), A １ From the viewpoint of ease of desorption and insertion of magnesium ions or calcium ions, the metal ion is preferably at least one selected from the group consisting of H, Li, Na, K, Ca, Mg, Ba, Sr, Pb, Cu, and Ag, and more preferably at least one selected from the group consisting of Li and Na.

[0030] In general formula (1A), M１ From the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, the metal is preferably at least one selected from the group consisting of Mg, Ca, Ti, Si, Ge, Sn, Ni, Co, Cu, and Zn, and more preferably at least one selected from the group consisting of Mg, Ca, Ni, Co, Cu, and Zn.

[0031] In general formula (1A), D is preferably at least one selected from the group consisting of Te, Sb, Bi, Ru, Nb, Ta, Sn, and W, and more preferably at least one selected from the group consisting of Te, Sb, Bi, and Ru, from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions.

[0032] In general formula (1A), A １ , M １ , and the combination of D (A １ , M １ , D), from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, (Li,Ni,Te), (Li,Co,Te), (Li,Cu,Te), (Li,Mg,Te), (Li,Zn,Te), (Li,Ca,Te), (Na,Ni,Te), (Na,Co,Te), (Na,Cu,Te), (Na,Mg,Te), (Na,Zn,Te), (Na,Ca,Te), (Ba,Ni,Te), (Na,Ni,Ru), (Na,Co,Ru), (Na,Ni ０．５ Co ０．５ , Ru), (Na, Ni, Bi), (Na, Co, Bi), (Na, Ni ０．５ Co ０．５ , Bi), (Na, Ca, Bi), (Na, Ni, Sb), (Na, Co, Sb), (Na, Ni ０．５ Co ０．５, Sb), (Na, Mg, Sb), (Na, Ca, Sb), (K, Ni, Te), (K, Co, Te), (K, Cu, Te), (K, Mg, Te), (Ag, Ni, Te), (Ag, Co, Te), (Ag, Cu, Te), (Ag, Mg, Te), (Ag, Zn, Te ), (Ag, Ca, Te), (Cu, Ni, Te), (Cu, Co, Te), (Cu, Mg, Te), (Cu, Zn, Te), (Cu , Ca, Te), (Li, Ni, W), (Li, Co, W), (Li, Fe, W), (Li, Mg, W), (Li, Zn, W), (Li , Ca, W), (Li, Mn, W), (Li, Ni, Bi), (Li, Co, Bi), (Li, Cu, Bi), (Li, Mg, Bi) , (Li, Zn, Bi), (Li, Ni, Ru), (Li, Co, Ru), (Li, Mg, Ru), (Li, Zn, Ru), (Li, Z n, Ru), (Li, Ni, Ta), (Li, Co, Ta), (Li, Ni, Nb), (Li, Mg, Sn), (Li, Zn, Ru) , (Li, Mn, Sb), (Li, Fe, Sb), (Li, Co, Sb), (Li, Ga, Sb), and (Li, Al, Sb) are preferred.

[0033] In general formula (1A), the value of a1 is preferably 1≦a1≦5, more preferably 2≦a1≦4, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0034] In general formula (1A), the value of m1 is preferably 0.5≦m1≦2, more preferably 1≦m1≦2, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0035] In general formula (1A), the value of d is preferably 0.5≦d≦1, and more preferably 0.8≦d≦1, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0036] In general formula (1A), the combination of a1, m1, and d (a1, m1, d) is preferably (3 to 5, 0.5 to 1.5, 0.5 to 1), (1 to 3, 1 to 2, 0.5 to 1), (2 to 4, 1 to 2, 0.5 to 1), more preferably (3.5 to 4.5, 0.8 to 1.2, 0.8 to 1), (1.5 to 2.5, 1.5 to 2, 0.8 to 1), (2.5 to 3.5, 1.3 to 1.7, 0.8 to 1), (2.5 to 3.5, 1.5 to 2, 0.8 to 1), and even more preferably (4,1,1), (2,2,1), (1,2,1), (3,1.5,1), or (3,2,1).

[0037] As the compound represented by the general formula (1A), from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions, Li ４ NiTeO ６ , Li ４ CoTeO ６ , Li ４ CuTeO ６ , Li ４ MgTeO ６ , Li ４ ZnTeO ６ , Na ４ NiTeO ６ , Na ４ CoTeO ６ , Na ４ CuTeO ６ , Na ４ MgTeO ６ , Na ４ ZnTeO ６ , Na ４ CaTeO ６ , Na ４ FeTeO ６ , Na ４ MnTeO ６ , Li ２ Ni ２ TeO ６ , Li ２ Co ２ TeO ６ , Li ２ Cu ２ TeO ６ , Li ２ Mg ２ TeO６ 、i ２ : ２ () ６ 、a ２ i ２ () ６ 、a ２ o ２ () ６ 、a ２ u ２ () ６ 、a ２ *| ２ () ６ 、a ２ : ２ () ６ 、!ｮ) ２ () ６ 、a ３ i １．５ () ６ 、a ３ o １．５ () ６ 、a ３ u １．５ () ６ 、a ３ *| １．５ () ６ 、a ３ : １．５ () ６ 、a ３ i ２ 2) ６ 、a ３ o ２ 2) ６ 、a ３ )|o)ｯ ６ 、a ３ *| ２ ___ ６ 、a ３ i ２ fi ６ 、a ３ o ２ fi ６ 、a ３ )oB ６ 、a ３ i ２ __ ６ 、a ３ o ２ __ ６ 、a ３ )o+O ６、! ３ i １／３ fi １／３ . １／３ * １／３ fi １／３ * １／３ 3 ６ 、i ４ .. ６ 、i ４ pi? ６ 、i ４ * ６ 、i ４ ____ ６ 、i ４ .. ６ 、i ４ _____ ６ 、; ２ i ２ () ６ 、; ２ fi ２ () ６ 、; ２ * ２ () ６ 、; ４ i) O ６ 、; ４ o) ﯁ ６ 、i ２ * ６ 、i ２ .. ６ 、i ２ ()) (4) ６ 、i ２ 3) 4 ６ 、i ２ _____ ６ 、! ２ ()) (4) ６ 、! ２ 3) 4 ６ 、! ２ .. ６ 、! ２ _____ ６ 、.1 ４ i) O ６ 、.1 ４ o) ﯁ ６ 、.1 ４ pi ６ 、.1 ４ / / ) ６ 、.1 ４ .!﯁６ , Li ３ Ni ２ Bio ６ , Li ３ Co ２ Bio ６ 、Li ３ Cu ２ Bio ６ , Li ３ Mẽ ２ Bio ６ 、Li ３ Zhậu ２ Bio ６ 、Ag ３ Ni ２ Bio ６ 、Ag ２ Co ２ Bio ６ 、Ag ２ Cu ２ Bio ６ 、Ag ２ Mẽ ２ Bio ６ 、Ag ２ Zhậu ２ Bio ６ , Li ３ Ni ２ Sbｯ ６ 、Li ３ Co ２ Sbｯ ６ 、Li ３ Cu ２ Sbｯ ６ , Li ３ Mẽ ２ Sbｯ ６ , Li ３ Zhậu ２ Sbｯ ６ 、Ag ２ Ni ２ Tet ６ 、Ag ２ Co ２ Tet ６ 、Ag ２ Cu ２ Tet ６ 、Ag ２ Mẽ ２ Tet ６ 、Ag ２ Zhậu ２ Tet ６ 、Ag ２ MnTeO ６ 、Ag ２GeTeO ６ , Ag ２ TiTeO ６ , Ag ２ SnTeO ６ , Ag ２ ZrTeO ６ , Cu ２ Ni ２ TeO ６ , Cu ２ Co ２ TeO ６ , Cu ４ TeO ６ , Cu ２ Mg ２ TeO ６ , Cu ２ Zn ２ TeO ６ , Li ３ Ni ２ TaO ６ , Li ３ Co ２ TaO ６ , Li ３ Ni ２ NbO ６ is preferred.

[0038] (B) The precursor compound according to the second aspect is represented by the general formula (1B): ２ ａ２ M ２ ｍ２ E ２ O ７-δ (1B) [wherein, A ２ is at least one selected from the group consisting of Li, Na, K, Rb, Cs, Ba, Sr, Pb, Cu, and Ag, and M ２ is at least one selected from the group consisting of Mg, Al, Ca, Fe, Ti, V, Ni, Cu, Mn, Co, and Zn, and E is at least one selected from the group consisting of V, Si, Ge, P, W, S, and B, and 0<a2≦4, 0<m2≦2, −2≦δ≦2.] The composite oxide obtained in this case is a compound represented by the following general formula (1B′).

[0039] In general formula (1B), A ２As the element, from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, at least one element selected from the group consisting of Li, Na, K, Rb, Ba, and Sr is preferred, and at least one element selected from the group consisting of Li, Na, and K is more preferred.

[0040] In general formula (1B), M ２ As the metal, from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, at least one selected from the group consisting of Ni, Cu, Mn, V, Fe, Ca, Zn, and Co is preferable, and at least one selected from the group consisting of Ni, Cu, Mn, and Co is more preferable.

[0041] In general formula (1B), E is preferably at least one selected from the group consisting of V, Si, Ge, and P, and more preferably P, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0042] In general formula (1B), A ２ , M ２ , and the combination of E (A ２ , M ２ , E), from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, (K,Cu,P), (K,Mn,P), (K,Co,P), (K,Ni,P), (K,Fe,P), (K,Zn,P), (K,Zn,V), (K,V,P), (K,Ca,P), (K,Mg,P), (K,Mn,V), (K,Mg,V), (Na,Cu,P), (Na, Mn, P), (Na, Co, P), (Na, Ni, P), (Na, Fe, P), (Na, Zn, P), (Na, Zn, V), (Na, Ca, P), (Na, Mg, P), (Li, Cu, P) , (Li,Mn,P), (Li,Co,P), (Li,Ni,P), (Li,Fe,P), (Li,Zn,P), (Li,Zn,V), (Li,Ca,P), and (Li,Mg,P) are preferred.

[0043] In general formula (1B), the value of a2 is preferably 0.5≦a2≦2.5, more preferably 1≦a2≦2, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0044] In general formula (1B), the value of m2 is preferably 0.5≦m2≦1.5, more preferably 0.8≦m2≦1.2, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0045] In general formula (1B), the combination of a2 and m2 (a2, m2) is preferably (1 to 3, 0.5 to 1.5), (0.1 to 1.5, 0.5 to 1.5), more preferably (1.5 to 2.5, 0.8 to 1.2), or (0.5 to 1.5, 0.8 to 1.2), and even more preferably (2,1) or (1,1), from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0046] In general formula (1B), the value of δ is preferably −0.5≦δ≦1, more preferably −0.2≦δ≦0.5, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0047] As the compound represented by the general formula (1B), from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions, K ２ CuP ２ O ７ , K. ２ MnP ２ O ７ , K. ２ CoP ２ O ７ , K. ２ NiP ２ O ７ , K. ２ FeP ２ O ７ , K. ２ CaP ２ O ７ , K. ２ MgP ２ O ７ , K. ２ ZnP ２ O ７ , K.２ MnV ２ O ７ 、K ２ MgV ２ O ７ 、K ２ CaV ２ O ７ 、K ２ ZnV ２ O ７ 、Na ２ CuP ２ O ７ 、Na ２ MnP ２ O ７ 、Na ２ CoP ２ O ７ 、Na ２ NiP ２ O ７ 、Na ２ FeP ２ O ７ 、Na ２ CaP ２ O ７ 、Na ２ MgP ２ O ７ 、Na ２ ZnP ２ O ７ 、Na ２ ZnV ２ O ７ 、Li ２ CuP ２ O ７ 、Li ２ MnP ２ O ７ 、Li ２ CoP ２ O ７ 、Li ２ NiP ２ O ７ 、Li ２ FeP ２ O ７ 、Li ２ CaP ２ O ７ 、Li ２ MgP ２ O ７ 、Li ２ ZnP ２ O ７ 、Li ２ Ni ２ W ２O ９ , Li ２ Cu ２ S ２ O ９ is preferred.

[0048] (C) The precursor compound according to the third aspect is represented by the general formula (1C): ３ ａ３ M ３ ｍ３ GO ４ (1C) [wherein, A ３ is at least one selected from the group consisting of Li, Na, K, Rb, Cs, Ca, Mg, Ba, Sr, Cu, and Ag, and M ３ is at least one selected from the group consisting of Mg, Al, Ca, Ni, Fe, Mn, Co, Cu, and Zn, and G is at least one selected from the group consisting of Si, Ge, Ti, Sn, Mn, V, and Zr, and 0<a3≦2, 0<m3≦1.] The composite oxide obtained in this case is a compound represented by the following general formula (1C′).

[0049] In general formula (1C), A ３ As the metal, from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, at least one selected from the group consisting of Li, Na, K, Rb, and Cs is preferred, and at least one selected from the group consisting of Li, Na, and K is more preferred.

[0050] In general formula (1C), M ３ As the element, from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, at least one element selected from the group consisting of Mg, Ca, Fe, Mn, Zn, and Co is preferred, and at least one element selected from the group consisting of Fe and Ca is more preferred.

[0051] In the general formula (1C), G is preferably at least one selected from the group consisting of Si, Ge and Ti, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0052] In general formula (1C), A ３ , M３ , and the combination of G (A ３ , M ３ , G), from the viewpoint of ease of desorption / insertion and / or conduction of magnesium ions or calcium ions and desorption / insertion capacity, (K, Mg, Si), (K, Fe, Si), (K, Ca, Si), (K, Fe, Ti), (K, Fe, Ge), (K, Mn, Si), (K, Zn, Si), (K, Co, Si), (K, Co, Ge), (K, Mg, Ge), (K, Zn, Ti), (K, Zn, Ge), (Na, Fe, Si), (Na, Ca, Si), (Na, Fe, Ti), ( (Na, Fe, Ge), (Na, Mn, Si), (Na, Zn, Si), (Na, Co, Si), (Na, Co, Ge), (Na, Mg, Ge), (Na, Zn, Ti), (Na, Zn, Ge), (Li, Fe, Si), (Li, Ca, S i), (Li, Fe, Ti), (Li, Fe, Ge), (Li, Mn, Si), (Li, Zn, Si), (Li, Co, Si), (Li, Co, Ge), (Li, Mg, Ge), (Li, Zn, Ti), (Li, Zn, Ge) are preferred.

[0053] In general formula (1C), the value of a3 is preferably 1≦a3≦3, more preferably 1.5≦a3≦2.5, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0054] In general formula (1C), the value of m3 is preferably 0.5≦m3≦1.5, more preferably 0.8≦m3≦1.2, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0055] In general formula (1C), the combination of a3 and m3 (a3, m3) is preferably (1 to 3, 0.5 to 1.5), more preferably (1.5 to 2.5, 0.8 to 1.2), and even more preferably (2, 1), from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0056] As the compound represented by the general formula (1C), from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, K ２ MgSiO４ , K ２ FeSiO ４ , K ２ CaSiO ４ , K ２ FeTiO ４ , K ２ FeGeO ４ , K ２ MnSiO ４ , K ２ CoGeO ４ , K ２ CoSiO ４ , K ２ ZnSiO ４ , K ２ ZnGeO ４ , Na ２ FeSiO ４ , Na ２ CaSiO ４ , Na ２ FeTiO ４ , Na ２ FeGeO ４ , Na ２ MnSiO ４ , Li ２ [[ID=5৯]]FeSiO ４ , Li ２ CaSiO ４ , Li ２ FeTiO ４ , Li[[ID=7০]] ２ FeGeO ４ , Li ２ MnSiO ４ , Li ２ NiTiO ４ , Li ２ MnTiO ４ , Li ２ CoGeO ４ , Li ２ ZnGeO ４ , Na ２ CoGeO ４ , Na ２ CoSiO ４ , Na ２ ZnSiO ４ , Na ２ ZnGeO ４ are preferred.

[0057] (D) The precursor compound according to the fourth aspect has the general formula (1D): A ４ａ４ M ４ ｍ４ (G'O ４ ) ｇ (1D) [wherein, A ４ is at least one selected from the group consisting of Li, Na, K, Rb, Cs, Ba, Ca, Mg, Sr, Pb, Cu, and Ag, and M ４ is at least one selected from the group consisting of Mg, Al, Ca, Ni, Cu, Zn, Fe, Mn, V, and Ti, and G' is at least one selected from the group consisting of Si, Ge, P, S, W, Mo, and Zr, and 0<a4≦6, 0<m4≦2, 2≦g≦6.] The composite oxide obtained in this case is a compound represented by the following general formula (1D').

[0058] In general formula (1D), A ４ As the metal, from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, at least one selected from the group consisting of Li, Na, K, Rb, and Cs is preferred, and at least one selected from the group consisting of Li, Na, and K is more preferred.

[0059] In general formula (1D), M ４ As the metal, from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, at least one selected from the group consisting of Ni, Cu, Zn, Fe, Mn, V, and Ti is preferred, and at least one selected from the group consisting of V and Ti is more preferred.

[0060] In general formula (1D), G' is preferably at least one selected from the group consisting of Si, P, W, and S, and more preferably at least one selected from the group consisting of P and S, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0061] In general formula (1D), A ４ , M ４ , and the combination of G′ (A ４ , M ４, G'), from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, (K,V,P), (K,V,S), (K,Fe,P), (K,Mn,S), (K,Fe,S), (K,Co,S), (K,Ni,S), (K,Ca,S), (K,Mg,S), (K,Zn,S), (Na,V,P), (Na,V,S), (Na,Fe,P), (Na , Mn, S), (Na, Fe, S), (Na, Co, S), (Na, Ni, S), (Na, Ca, S), (Na, Mg, S), (Na, Zn, S), (Li, V, P), (Li, V, S), (Li, Fe, P), (Li, Mn, S), (Li, Fe, S), (Li, Co, S), (Li, Ni, S), (Li, Ca, S), (Li, Mg, S), and (Li, Zn, S) are preferred.

[0062] In general formula (1D), the value of a4 is preferably 1≦a4≦4, and more preferably 2≦a4≦4, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0063] In general formula (1D), the value of m4 is preferably 0.5≦m4≦2, more preferably 1≦m4≦2, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0064] In general formula (1D), the combination of a4 and m4 (a4, m4) is preferably (2 to 4, 1 to 2), (2 to 4, 1 to 2), or (1 to 3, 0.5 to 2), more preferably (3 to 4, 1.5 to 2), (2.5 to 3.5, 1.5 to 2), or (1.5 to 2.5, 0.5 to 1.5), and even more preferably (4, 2), (3, 2), or (2, 1), from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0065] In general formula (1D), the value of g is preferably 2≦g≦4, more preferably 2.5≦g≦3.5, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0066] As the compound represented by general formula (1D), from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, K ２ V (SO ４ ) ２ , K. ３ V ２ (P.O. ４ ) ３ , K. ４ V ２ (P.O. ４ ) ３ , K. ２ VO (SO ４ ) ２ , K. ３ V (PO ４ ) ２ , K. ６ V ２ (P.O. ４ ) ４ , K. ２ Fe(SO ４ ) ２ , K. ２ Mn(SO ４ ) ２ , K. ２ Co(SO ４ ) ２ , K. ２ Ca(SO ４ ) ２ , K. ２ Mg(SO ４ ) ２ , K. ２ Ni(SO ４ ) ２ , K. ２ Zn(SO ４ ) ２ , K. ２ Fe ２ (SO ４ ) ３ , K. ２ Mn ２ (SO ４ ) ３ , K. ２ Co ２ (SO ４ ) ３ , K. ２ Ca ２ (SO ４ ) ３ , K. ２ Mg ２ (SO ４ )３ 、K ２ Zn ２ (SO ４ ) ３ 、K ２ Cu ２ (SO ４ ) ３ 、K ２ Ni ２ (SO ４ ) ３ 、N ２ VOO ４ ) ２ 、N ３ V ２ (2O ４ ) ３ 、N ４ V ２ (2O ４ ) ３ 、N ２ 4O(SO ４ ) ２ 、N ３ VOO ４ ) ２ 、N ２ Fe(SO ４ ) ２ 、N ２ ... ４ ) ２ 、N ２ Mn(SO ４ ) ２ 、N ２ Co(SO ４ ) ２ 、N ２ CK(SO ４ ) ２ 、N ２ MOOO ４ ) ２ 、N ２ Fe ２ (SO ４ ) ３ 、N ２ Mn ２ (SO ４ ) ３ 、N ２ Co ２ (SO ４ ) ３ 、N ２ Ca ２ (SO ４ ) ３ 、N ２MM ２ (SO ４ ) ３ 、N ２ Zn ２ (SO ４ ) ３ 、N ２ Cu ２ (SO ４ ) ３ 、N ２ Ni ２ (SO ４ ) ３ 、N ６ Mn(SO ４ ) ４ 、N ６ Fe(SO ４ ) ４ 、N ６ Co(SO ４ ) ４ 、N ６ MOOO ４ ) ４ 、N ６ ... ４ ) ４ 、 ３ V ２ (2O ４ ) ３ 、 ４ V ２ (2O ４ ) ３ 、 ２ 4O(SO ４ ) ２ 、 ２ Fe(SO ４ ) ２ 、 ２ ... ４ ) ２ 、 ２ Mn(SO ４ ) ２ 、 ２ Co(SO ４ ) ２ 、 ２ CK(SO ４ ) ２ 、 ２ MOOO ４ ) ２ 、 ２ Fe ２ (SO ４ ) ３ 、 ２Mn ２ (SO ４ ) ３ , Li ２ Co ２ (SO ４ ) ３ , Li ２ Ca ２ (SO ４ ) ３ , Li ２ Mg ２ (SO ４ ) ３ , Li ２ Zn ２ (SO ４ ) ３ , Li ２ Cu ２ (SO ４ ) ３ , Li ２ Ni ２ (SO ４ ) ３ , Li ２ Ni(WO ４ ) ２ , Li ２ Co (WO ４ ) ２ , Li ２ Cu(WO ４ ) ２ , Li ２ Mg ２ (W.O. ４ ) ３ , Li ２ Mg ２ (MoO ４ ) ３ , Li ２ Fe ２ (MoO ４ ) ３ , Li ２ Mn ２ (MoO ４ ) ３ , Li ２ Co ２ (MoO ４ ) ３ , Li ２ Cu ２ (MoO ４ ) ３ is preferred.

[0067] (E) The precursor compound according to the fifth aspect is represented by the general formula (1E): ５ａ５ M ５ ｍ５ P.O. ４ B (1E) [wherein, A ５ is at least one selected from the group consisting of Li, Na, K, Rb, Cs, Ba, Ca, Mg, Sr, Pb, Cu, and Ag, and M ５ is at least one selected from the group consisting of Mg, Al, Ca, Ni, Cu, Zn, Fe, Mn, V, Co and Ti, and B is F, Cl, OH and CO ３ and 0<a5≦2, 0<m5≦2.] The composite oxide obtained in this case is a compound represented by the general formula (1E′) described later.

[0068] In general formula (1E), A ５ As the metal, from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, at least one selected from the group consisting of Li, Na, K, Rb, and Cs is preferred, and at least one selected from the group consisting of Li, Na, and K is more preferred.

[0069] In general formula (1E), M ５ As the metal, from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, at least one selected from the group consisting of Ni, Cu, Zn, Fe, Mn, V, and Ti is preferable, and at least one selected from the group consisting of Fe and Mn is more preferable.

[0070] In general formula (1E), from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions, B is preferably at least one selected from the group consisting of F, Cl, and OH, and more preferably at least one selected from the group consisting of F and Cl.

[0071] In general formula (1E), A ５ , M ４ , and the combination of B (A ５ , M ４, B), from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, (K,Fe,Cl), (K,Mn,Cl), (K,Mn,F), (K,Fe,OH), (K,Fe,F), (Na,Fe,Cl), (Na,Mn,OH), (Na,Mn,Cl), (Na,Mn,F), (Na,Fe,OH), (Na,Fe,F), (Na,Co,OH), (Na,Co , Cl), (Na, Co, F), (Na, Ni, OH), (Na, Ni, Cl), (Na, Ni, F), (Li, Fe, Cl), (Li, Mn, OH), (Li, Mn, Cl), (Li, Mn, F), Preferred are (Li, Fe, OH), (Li, Fe, F), (Li, Co, OH), (Li, Co, Cl), (Li, Co, F), (Li, Ni, OH), (Li, Ni, Cl), and (Li, Ni, F).

[0072] In general formula (1E), the value of a5 is preferably 1≦a5≦2, and more preferably 1.5≦a5≦2, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0073] In general formula (1E), the value of m5 is preferably 0.5≦m5≦1.5, more preferably 0.8≦m5≦1.2, from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0074] In general formula (1E), the combination of a5 and m5 (a5, m5) is preferably (1 to 2, 0.5 to 1.5), more preferably (1.5 to 2, 0.8 to 1.2), and even more preferably (2, 1), from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions.

[0075] As the compound represented by the general formula (1E), from the viewpoint of ease of insertion / elimination and / or conduction of magnesium ions or calcium ions, K ２ FePO ４ Cl, K ２ MnPO ４ Cl, K ２ MnPO ４ F.K. ２ FePO ４ O.H.K. ２FePO ４ F.K. ２ CoPO ４ F, Na ２ CoPO ４ F, Na ２ FePO ４ OH, Na ２ FePO ４ F, Na ２ FePO ４ Cl, Na ２ MnPO ４ F, Li ２ NiPO ４ F, Li ２ CoPO ４ F, Li ２ FePO ４ F, Li ２ MnPO ４ F, Li ２ MgPO ４ F, Li ２ FePO ４ OH, Li ２ FePO ４ Cl, Li ２ MnPO ４ OH is preferred.

[0076] The precursor compound used in the present invention is preferably a compound represented by general formula (1A), a compound represented by general formula (1B), or a compound represented by general formula (1C), from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, and more preferably a compound represented by general formula (1A).

[0077] The precursor compound used in the present invention is not particularly limited, and examples thereof include layered, honeycomb layered, corundum type, ilmenite type, magniotriplite type, triplite type, zwieselite type, panasqueiraite type, sarkinite type, triplodite type, wagnerite type, wolfeite type, wadsleyite type, forsterite type, fayalite type, kirschsteinite type, hedenbergite type, johannsenite type, andradite type, uvarovite type, ferroactinolite type, kutnahorite type, ankerite type, marokite type, yafsoanite type, goldmanite type, gehlenite type, monticellite type, hardystonite type, melilite type, lyonsite type, krohnkite type, sideronatrite type, blodite type, leonite type, konyaite type, syngenite type, astrakanite type, cyanochroite type, and collinsite type. type, rock salt type, cristoballite type, spinel type, perovskite type, tunnel type, langbeinite type, fedotovite type, NASICON type, anti-NASICON type, tridymite type, LISICON type, vanthoffite type, eldfellite type, alluaudite type, yavapaiite type, KTiOPO4 type, wurtzite type, zircon type, nyerereite type, gaylussite type, pirssonite type, eitelite type, zemkorite type, sh Ortite type, olivine type, thortveitite type, garnet type, saranchinaite type, zircon type, tavorite type, sillimanite type, kotoite type, jimboite type, takedaite type, glaucochroite type, cristobalite type, kirschsteinite type, kirschsteinite-type olivine framework structure, monticellite type, pyroxene type, leucite type, Ca3ReO6 type, tungsten bronze type, Wadsley-RothIt can have a block type or corundum-like defect type crystal structure.

[0078] The precursor compound used in the present invention may be a commercially available product, or may be separately synthesized and used.

[0079] The precursor compounds used in the present invention may be used alone or in combination of two or more.

[0080] Among the precursor compounds used in the production method of the present invention or a similar production method, Na ４ MgTeO ６ , Na ４ CaTeO ６ , Na ３ Mg １．５ TeO ６ , Na ３ Zn １．５ TeO ６ , Na ３ Co ２ RuO ６ , Li ２ Zn ２ TeO ６ , Na ３ Co １．５ TeO ６ , Na ３ Cu １．５ TeO ６ , Na ３ Mg ２ RuO ６ , Na ３ Co ２ Bio ６ , Na ３ NiCoBiO ６ , Na ３ Ca ２ SbO ６ , or Na ３ NiCoSbO ６ The compound represented by the formula (I) is a novel compound that has not been described in any literature.

[0081] 1-2. Target Product The target composite oxide of the present invention contains magnesium or calcium, and specifically is any one of the following (1A'), (1B'), (1C'), (1D'), and (1E') depending on the combinations (A) to (E) of the precursor compound and the composite oxide as raw materials.

[0082] (A) In the case of the first aspect, that is, when the precursor compound is a compound represented by the general formula (1A), the composite oxide is a compound represented by the general formula (1A'): ａ１／２ M １ ｍ１ D ｄ O ６ (1A') [wherein X is Mg or Ca, provided that X is the same as the A １ The other symbols are the same as above.]

[0083] (B) In the case of the second embodiment, that is, when the precursor compound is a compound represented by the general formula (1B), the composite oxide is a compound represented by the general formula (1B'): ａ２／２ M ２ ｍ２ E ２ O ７-δ (1B') [wherein X is Mg or Ca, and X is the same as A ２ The other symbols are the same as above.]

[0084] (C) In the case of the third aspect, that is, when the precursor compound is a compound represented by the general formula (1C), the composite oxide is a compound represented by the general formula (1C'): ａ３／２ M ３ ｍ３ GO ４ (1C') [wherein X is Mg or Ca, and X is the same as A ３ The other symbols are the same as above.]

[0085] (D) In ​​the case of the fourth aspect, that is, when the precursor compound is a compound represented by the general formula (1D), the composite oxide is a compound represented by the general formula (1D'): ａ４／２ M ４ ｍ４ (G'O ４ ) ｇ (1D') [wherein X is Mg or Ca, and X is the same as A ４ The other symbols are the same as above.]

[0086] (E) In the case of the fifth aspect, that is, when the precursor compound is a compound represented by the general formula (1E), the composite oxide is a compound represented by the general formula (1E'): ａ５／２ M ５ ｍ５ P.O. ４ B (1E') [wherein X is Mg or Ca, and X is the same as A ５ The other symbols are the same as above.]

[0087] From the viewpoint of yield, the composite oxide obtained by the production method of the present invention is preferably a compound represented by general formula (1A'), a compound represented by general formula (1B'), or a compound represented by general formula (1C'), and more preferably a compound represented by general formula (1A').

[0088] The composite oxide obtainable by the production method of the present invention is not particularly limited, and examples thereof include layered, honeycomb layered, corundum type, ilmenite type, magniotriplite type, triplite type, zwieselite type, panasqueiraite type, sarkinite type, triplodite type, wagnerite type, wolfeite type, wadsleyite type, forsterite type, kirschsteinite type, hedenbergite type, johannsenite type, andradite type, uvarovite type, ferroactinolite type, kutnahorite type, ankerite type, marokite type, yafsoanite type, goldmanite type, gehlenite type, monticellite type, hardystonite type, melilite type, lyonsite type, krohnkite type, sideronatrite type, blodite type, leonite type, konyaite type, syngenite type, astrakanite type, cyanochroite type, collinsite type, Rock salt type, Cristoballite type, Spinel type, Perovskite type, Tunnel type, Langbeinite type, Fedotovite type, NASICON type, Anti-NASICON type, Tridymite type, LISICON type, Vanthoffite type, Eldfellite type, Alluaudite type, Yavapaiite type, KTiOPO4 type, Wurtzite type, Zircon type, Nyerereite type, Gaylussite type, Pirsonite type, Eitelite type, Zemkorite type, Sho rtite type, olivine type, thortveitite type, garnet type, saranchinaite type, zircon type, tavorite type, sillimanite type, kotoite type, jimboite type, takedaite type, glaucochroite type, cristobalite type, kirschsteinite type, kirschsteinite-type olivine framework structure, monticellite type, pyroxene type, leucite type, Ca3ReO6 type, tungsten bronze type, Wadsley-RothThe composite oxide obtained by the production method of the present invention may have a crystal structure of a block type or a corundum-like defect type. Preferably, the composite oxide obtained by the production method of the present invention has the same crystal structure as the precursor compound used.

[0089] From the viewpoint of obtaining a novel crystal structure, the composite oxide obtained by the production method of the present invention is preferably a compound obtained by replacing the cations constituting the precursor compound as a raw material with magnesium ions or calcium ions constituting the salt described below. Here, the cations constituting the precursor compound are, in the case of (A) above, A １ In the case of (B) above, A ２ In the case of (C) above, A ３ In the case of (D) above, A ４ In the case of (E) above, A ５ It is preferable that:

[0090] The ion exchange reaction is not particularly limited, but is preferably a topochemical reaction or a metathesis reaction, and more preferably a topochemical reaction. Herein, the term "metathesis reaction" refers to a broad element (ion) recombination reaction that occurs between a precursor compound and a salt, and is a concept that encompasses topochemical reactions. Furthermore, the term "topochemical reaction" refers to an ion exchange reaction (particularly, a metathesis reaction) in which the structure (particularly, the crystal structure) does not change before and after the reaction, and is a concept that encompasses metathesis reactions. In these cases, the crystal structure of the resulting composite oxide is basically identical to the crystal structure of the precursor compound used. On the other hand, for example, magnesium ions or calcium ions constituting the salt may be inserted or substituted at different crystallographic positions. Therefore, the crystal structure of the resulting composite oxide may differ from the crystal structure of the precursor compound that is the raw material.

[0091] For the above reasons, the composite oxide obtained by the production method of the present invention may have a different crystal structure than the composite oxide obtained by the conventional solid-phase synthesis method, despite having substantially the same chemical composition. The crystal structure of the composite oxide obtained by the production method of the present invention is preferably a metastable phase. Furthermore, for the same reasons, the composite oxide obtained by the production method of the present invention may exhibit a different color than the composite oxide obtained by the conventional solid-phase synthesis method, despite having substantially the same chemical composition.

[0092] The composite oxide obtained by the production method of the present invention may contain other elements to the extent that the effects of the present invention are not impaired, preferably about 5% by mass or less, more preferably about 1% by mass or less, and even more preferably about 0.1% by mass or less.

[0093] Other elements that may be contained in the composite oxide include inevitable impurities derived from the raw materials, as well as dopants. Examples of dopants that may be contained in the composite oxide include lanthanides such as europium, dysprosium, samarium, and thulium, and transition metals such as manganese. In the production method of the present invention, a raw material containing such a dopant is added to a precursor compound in the heating step, thereby obtaining a composite oxide containing a certain amount of the dopant.

[0094] The composition and structure of the composite oxide can be determined, for example, by X-ray diffraction (XRD).

[0095] The average particle size of the composite oxide is not particularly limited, but from the viewpoint of obtaining a composite oxide of a size that cannot be obtained by conventional solid-phase synthesis, it is preferably 1 nm to 100 nm, more preferably 10 nm to 80 nm, and even more preferably 20 nm to 50 nm. The average particle size can be determined, for example, by an ultra-high resolution scanning electron microscope or an ultra-high resolution transmission electron microscope.

[0096] The composite oxides obtained by the production method of the present invention can be obtained either alone or in combination of two or more kinds.

[0097] Specific examples of magnesium composite oxides obtainable by the production method of the present invention include MgFeSiO ４、!gｭ･iｯ ４ 、|| ２ three) ４ 、||||3) ４ 、||||___i ４ 、; ４ 、||||___ｯ ４ 、; ４ 、||||||||| ４ 、||||||| ４ 、|| ２ e﯁ ４ 、||||||| ４ 、||||||| ４ 、!ｮiieO ４ 、||||||| ４ 、||||||| ４ 、|||々 ２ 3) ２ . ７ 、|||| ２ 3) ２ . ７ 、|| ３ 3) ２ . ７ 、|||| ２ 3) ２ . ７ 、||||o ２ 3) ２ . ７ 、***) ２ 3) ２ . ７ 、|||| ２ 3) ２ . ７ 、|||_n ２ 3) ２ . ７ 、|| ２ F) ２ . ７ 、|| ２ *) ２ . ７ 、|| ２ pi ２ . ７ 、|| ２ pi) ２ . ７ 、|| ２ i) ２ . ７ 、|| ２ pi ２ . ７ 、||２ The sight ２ 9. The ７ 、N5 ２ 3 ２ 9. The ７ 、Nr ２ 3 ２ 9. The ７ 、N ３ 3 ２ 9. The ７ 、NH ２ 3 ２ 9. The ７ 、NH ２ 3 ２ 9. The ７ 、N9 ２ 3 ２ 9. The ７ 、N5 ２ 3 ２ 9. The ７ 、It is ２ 3 ２ 9. The ７ 、NEXT ２ 9. The ７ 、N16 ２ 9. The ７ 、N ２ 10 ２ 9. The ７ 、NH ２ 9. The ７ 、NEXT ２ 9. The ７ 、N91 ２ 9. The ７ 、N56 ２ 9. The ７ 、XI4 ２ 9. The ７ 、N.S ２ 9. The ７ 、Nr ２ 9. The ７ 、N ２ 6 ２ 9. The ７ 、NH ２ 9. The ７ 、NH ２ 9. The ７ 、N96 ２ 9. The ７ 、NH ２ 9. The ７ 、THE SIX ２ 9. The ７ 、NATHERI ４ 0. 100.000 ４F、Mg ２ PO ４ F、MgCaPO ４ F、MgCoPO ４ F、MgNiPO ４ F、MgCuPO ４ F、MgZnPO ４ F、MgFePO ４ OH、MgMnPO ４ OH、Mg ２ PO ４ OH、MgCaPO ４ OH、MgCoPO ４ OH、MgNiPO ４ OH、MgCuPO ４ OH、MgZnPO ４ OH、MgFePO ４ Cl、MgMnPO ４ Cl、Mg ２ PO ４ Cl、MgCaPO ４ Cl、MgCoPO ４ Cl、MgNiPO ４ Cl、MgCuPO ４ Cl、MgZnPO ４ Cl、MgFeTiO ４ 、MgMnTiO ４ 、Mg ２ TiO ４ 、MgCaTiO ４ 、MgCoTiO ４ 、MgNiTiO ４ 、MgCuTiO ４ 、MgZnTiO ４ 、MgMn ２ P ２ O ７ F ２ 、MgFe ２ TeO ６ 、MgMn ２ TeO ６ 、Mg ３ TeO ６ 、MgCa ２ TeO ６ 、MgCo ２ TeO ６ 、MgNi ２ TeO ６ 、MgCu ２ TeO ６ 、MgZn２ TeO ６ 、Mg １．５ Fe ２ SbO ６ 、Mg １．５ Mn ２ SbO ６ 、Mg ３．５ SbO ６ 、Mg １．５ Ca ２ SbO ６ 、Mg １．５ Co ２ SbO ６ 、Mg １．５ Ni ２ SbO ６ 、Mg １．５ NiCoSbO ６ 、Mg １．５ Cu ２ SbO ６ 、Mg １．５ Zn ２ SbO ６ 、Mg １．５ Fe ２ BiO ６ 、Mg １．５ Mn ２ BiO ６ 、Mg ３．５ BiO ６ 、Mg １．５ Ca ２ BiO ６ 、Mg １．５ Co ２ BiO ６ 、Mg １．５ Ni ２ BiO ６ 、Mg １．５ NiCoBiO ６ 、Mg １．５ Cu ２ BiO ６ 、Mg １．５ Zn ２ BiO ６ 、Mg １．５ Fe ２ RuO ６ 、Mg １．５ Mn ２ RuO ６ 、Mg ３．５ RuO ６ 、Mg １．５ Ca ２ RuO ６ 、Mg１．５ Co ２ RuO ６ 、Mg １．５ Ni ２ RuO ６ 、Mg １．５ Cu ２ RuO ６ 、Mg １．５ Zn ２ RuO ６ 、Mg ２ FeTeO ６ 、Mg ２ MnTeO ６ 、Mg ３ TeO ６ 、Mg ２ CaTeO ６ 、Mg ２ CoTeO ６ 、Mg ２ NiTeO ６ 、Mg ２ CuTeO ６ 、Mg ２ ZnTeO ６ 、Mg ２ FeSbO ６ 、Mg ２ MnSbO ６ 、Mg ３ SbO ６ 、Mg ２ CaSbO ６ 、Mg ２ CoSbO ６ 、Mg ２ NiSbO ６ 、Mg ２ CuSbO ６ 、Mg ２ ZnSbO ６ 、Mg ２ CrSbO ６ 、Mg ２ GaSbO ６ 、Mg ２ AlSbO ６ 、Mg １．５ Cu ２／５ Ni ２／５ Co ２／５ Fe ２／５ Mn ２／５ SbO ６ 、Mg １．５ Cu １／３ Ni １／３ Co １／３ Mg１／３ Mn １／３ Cu １／３ SbO ６ , Mg １．５ Fe １．５ TeO ６ , Mg １．５ Mn １．５ TeO ６ , Mg １．５ Ca １．５ TeO ６ , Mg １．５ Co １．５ TeO ６ , Mg １．５ Ni １．５ TeO ６ , Mg １．５ Cu １．５ TeO ６ , Mg １．５ Zn １．５ TeO ６ , Mg １．５ Ni ２ TaO ６ , Mg １．５ Co ２ TaO ６ , Mg １．５ Ni ２ NbO ６ , Mg ２ FeWO ６ , Mg ２ MnWO ６ , Mg ３ WO ６ , Mg ２ CaWO ６ , Mg ２ NiWO ６ , etc.

[0098] Specific examples of calcium composite oxides obtainable by the production method of the present invention include CaFeSiO ４ , CaMnSiO ４ , Ca ２ SiO ４ , CaMgSiO ４ , CaCoSiO ４ , CaNiSiO ４ , CaCuSiO ４ , CaZnSiO ４ , CaFeGeO ４ , CaMnGeO ４ , Ca ２GeO ４ 、CaMgGeO ４ 、CaCoGeO ４ 、CaNiGeO ４ 、CaCuGeO ４ 、CaZnGeO ４ 、CaFe ２ Si ２ O ７ 、CaMn ２ Si ２ O ７ 、Ca ３ Si ２ O ７ 、CaMg ２ Si ２ O ７ 、CaCo ２ Si ２ O ７ 、CaNi ２ Si ２ O ７ 、CaCu ２ Si ２ O ７ 、CaZn ２ Si ２ O ７ 、Ca ２ FeSi ２ O ７ 、Ca ２ MnSi ２ O ７ 、Ca ２ MgSi ２ O ７ 、Ca ２ CoSi ２ O ７ 、Ca ２ NiSi ２ O ７ 、Ca ２ CuSi ２ O ７ 、Ca ２ ZnSi ２ O ７ 、CaFe ２ B ２ O ７ 、CaMn ２ B ２ O ７ 、Ca ３ B ２ O ７ 、CaMg ２ B ２ O７ 、CaCo ２ B ２ O ７ 、CaNi ２ B ２ O ７ 、CaCu ２ B ２ O ７ 、CaZn ２ B ２ O ７ 、CaFeP ２ O ７ 、CaMnP ２ O ７ 、Ca ２ P ２ O ７ 、CaMgP ２ O ７ 、CaCoP ２ O ７ 、CaNiP ２ O ７ 、CaCuP ２ O ７ 、CaZnP ２ O ７ 、CaFeV ２ O ７ 、CaMnV ２ O ７ 、Ca ２ V ２ O ７ 、Ca ２ V ２ O ７ 、CaCoV ２ O ７ 、CaNiV ２ O ７ 、CaCuV ２ O ７ 、CaZnV ２ O ７ 、CaFePO ４ F、CaMnPO ４ F、Ca ２ PO ４ F、CaMgPO ４ F、CaCoPO ４ F、CaNiPO ４ F、CaCuPO ４ F、CaZnPO ４ F、CaFeTiO ４ 、CaMnTiO ４ 、Ca ２ TiO４ 、Ca~gtit ４ 、CaCoTiO ４ 、Caaliit ４ 、CaCuTiO ４ 、CaZnTiO ４ 、CaMn ２ P ２ O ７ F ２ 、Coffee ２ The ６ 、CaMn ２ The ６ 、Ca ３ The ６ 、CaMg ２ The ６ 、CaCo ２ The ６ 、CaNi ２ The ６ 、CaCu ２ The ６ 、CaZn ２ The ６ 、Ca １．５ Fe ２ Sbｯ ６ 、Ca １．５ Mn ２ Sbｯ ６ 、Ca ３．５ Sbｯ ６ 、Ca １．５ Mẽ ２ Sbｯ ６ 、Ca １．５ Co ２ Sbｯ ６ 、Ca １．５ No ２ Sbｯ ６ 、Ca １．５ Cu ２ Sbｯ ６ 、Ca １．５ Zhn ２ Sbｯ ６ 、Ca １．５ No １／３ Co １／３ Zhn １／３ Mẽ １／３ Cu １／３ Mn １／３ Sbｯ ６ 、Ca １．５ Fe ２ Bio ６ 、Ca １．５ Mn２ BiO ６ , Ca ３．５ BiO ６ , Ca １．５ Mg ２ BiO ６ , Ca １．５ Co ２ BiO ６ , Ca １．５ Ni ２ BiO ６ , Ca １．５ Cu ２ BiO ６ , Ca １．５ Zn ２ BiO ６ , Ca １．５ Fe ２ RuO ６ , Ca １．５ Mn ２ RuO ６ , Ca ３．５ RuO ６ , Ca １．５ Mg ２ RuO ６ , Ca １．５ Co ２ RuO ６ , Ca １．５ Ni ２ RuO ６ , Ca １．５ Cu ２ RuO ６ , Ca １．５ Zn ２ RuO ６ , Ca ２ FeTeO ６ , Ca ２ MnTeO ６ , Ca ３ TeO ６ , Ca ２ MgTeO ６ , Ca ２ CoTeO ６ , Ca ２ NiTeO ６ , Ca ２ CuTeO ６ , Ca ２ ZnTeO ６ , Ca ２ FeSbO ６ , Ca ２ MnSbO ６ , Ca３ SbO ６ , Ca ２ MgSbO ６ , Ca ２ CoSbO ６ , Ca ２ NiSbO ６ , Ca ２ CuSbO ６ , Ca ２ ZnSbO ６ , Ca ２ CrSbO ６ , Ca ２ GaSbO ６ , Ca ２ AlSbO ６ , Ca １．５ Cu ２／５ Ni ２／５ Co ２／５ Fe ２／５ Mn ２／５ SbO ６ , Ca １．５ Cu １／３ Ni １／３ Co １／３ Mg １／３ Mn １／３ Cu １／３ SbO ６ , Ca １．５ Fe １．５ TeO ６ , Ca １．５ Mn １．５ TeO ６ [[ID=7�]], Ca １．５ Mg １．５ TeO ６ , Ca １．５ Co １．５ TeO ６ , Ca １．５ Ni １．５ TeO ６ , Ca １．５ Cu １．５ TeO ６ , Ca １．５ Zn １．５ TeO ６ , Ca １．５ Ni ２ TaO ６ , Ca １．５ Co ２ TaO ６ , Ca １．５ Ni ２ NbO ６ , Ca２ FeWO ６ , Ca ２ MnWO ６ , Ca ３ WO ６ , Ca ２ MgWO ６ , Ca ２ CoWO ６ , Ca ２ NiWO ６ , etc.

[0099] Among the compounds obtained by the production method of the present invention or a similar production method, XMGeO ４ , XM ２ Si ２ O ７ , X ２ MSi ２ O ７ , XM ２ B ２ O ７ , XMV ２ O ７ , XMPO ４ F, XMTiO ４ , XMn ２ P ２ O ７ , XM ２ TeO ６ , X １．５ M ２ SbO ６ , X １．５ M ２ Bio ６ , X １．５ M ２ RuO ６ , X ２ MTeO ６ , X ２ MSbO ６ , X １．５ Cu ２／５ Ni ２／５ Co ２／５ Fe ２／５ Mn ２／５ SbO ６ , X １．５ Cu １／３ Ni １／３ Co １／３ Mg １／３ Mn １／３ Cu １／３ SbO ６ or X １．５ M１．５ TeO ６ [In each formula, X is Mg or Ca, and M is Fe, Mn, Mg, Ca, Co, Ni, Ni ０．５ Co ０．５ , Cu, or Zn.] is a novel compound not described in any literature.

[0100] Among the composite oxides obtained by the production method of the present invention, Na ２ Mg ２ TeO ６ Mg ３ TeO ６ The magnesium composite oxide represented by the formula (1) is a novel compound having a novel crystal structure not previously described in the literature. ２ Mg ２ TeO ６ The crystalline structure means an ilmenite-type crystalline structure.

[0101] Among the composite oxides obtained by the production method of the present invention, MgM ２ TeO ６ magnesium composite oxide represented by the formula: CaM ２ TeO ６ The calcium composite oxides represented by the following formula (where M is Mg, Co, Ni, Cu, or Zn) are novel compounds having a novel crystal structure that has not been described in any literature.

[0102] Thus, the composite oxide obtained by the production method of the present invention can have advantageous material properties based on a novel composition or structure, and for these reasons, the composite oxide obtained by the production method of the present invention can be useful as a battery material (e.g., an electrode material, a solid electrolyte material, etc.), an optical material, or a magnetic material.

[0103] Among the composite oxides obtained by the production method of the present invention, XM ２ TeO ６ , or XM ２ TeO ６[In each formula, X is Mg or Ca, and M is Fe, Mn, Mg, Ca, Co, Ni, Cu, or Zn.] The compound represented by the formula (I) is likely to have high ionic conductivity of the magnesium ion or calcium ion carrier ion. In this case, the ionic conductivity is 1×10 －６ SCM －１ It is preferable that the ratio is 1×10 or more. －５ SCM －１ The ionic conductivity is measured by an AC impedance method using a blocking electrode.

[0104] In particular, Mg ３ TeO ６ The compound represented by the formula (I) has a short distance between Mg sites, and therefore the ionic conductivity is likely to be significantly increased. ３ TeO ６ The compound represented by the formula (I) is useful as a solid electrolyte material.

[0105] Among the composite oxides obtained by the production method of the present invention, Ca ３.５ SbO ６ (especially perovskite type), Ca ２ ZnTeO ６ (especially perovskite type), CaZn ２ TeO ６ (especially ilmenite type), Mg ３ TeO ６ (especially vacant type), or CaMg ２ TeO ６ (particularly, ilmenite type) ３＋ , Dy ３＋ , Sm ３＋ , Tm ３＋ and Mn ４＋ When the compound is doped with at least one selected from the group consisting of the above, it is likely to become a luminescent material or a fluorescent material that emits a variety of luminescent colors.

[0106] The salt used in the present invention contains magnesium or calcium. For the sake of explanation only, when the salt contains magnesium, the composite oxide contains magnesium, and when the salt contains calcium, the composite oxide contains calcium.

[0107] The salt containing magnesium (magnesium-containing salt) is not particularly limited, and examples thereof include hydroxide, nitrate, sulfate, and halide of magnesium. More specifically, magnesium-containing salts include magnesium hydroxide, magnesium nitrate, magnesium sulfate, magnesium chloride, magnesium bromide, magnesium iodide, magnesium fluoride, and n-hydrates thereof. Among them, from the viewpoints of yield, melting point, and solubility in water, magnesium nitrate, magnesium sulfate, magnesium chloride, magnesium bromide, magnesium iodide, and n-hydrates thereof are preferred as magnesium-containing salts, more preferably magnesium nitrate, magnesium chloride, and n-hydrates thereof, and even more preferably magnesium chloride and n-hydrates thereof. Examples of the integer represented by n include 1, 2, 3, 4, 5, and 6.

[0108] The calcium-containing salt (calcium-containing salt) is not particularly limited, and examples thereof include calcium hydroxide, nitrate, and halides. More specific examples of calcium-containing salts include calcium hydroxide, calcium nitrate, calcium chloride, calcium bromide, calcium iodide, calcium fluoride, and n-hydrates thereof. Among these, from the viewpoints of yield, melting point, and solubility in water, calcium nitrate, calcium chloride, calcium bromide, calcium iodide, and n-hydrates thereof are preferred as calcium-containing salts, and calcium nitrate, calcium chloride, and n-hydrates thereof are more preferred. n is, for example, 1, 2, 3, 4, 5, or 6.

[0109] The salt may be a solid or a liquid (molten salt). Among these, the salt is preferably a molten salt from the viewpoint of yield.

[0110] The salts used in the present invention may be commercially available products, or may be separately synthesized and used.

[0111] The salts can be used alone or in combination of two or more.

[0112] When the salt is solid, the amount of salt used is preferably an excess amount, i.e., more than the stoichiometric amount relative to the target composite oxide, from the viewpoint of reaction rate. When the salt is a molten salt, the amount of salt used is preferably a substantially stoichiometric amount relative to the target composite oxide, and more preferably a stoichiometric amount, from the viewpoint of cost reduction. When multiple compounds are used as the salt, the amount of salt used means the total amount of each compound used.

[0113] The production method of the present invention includes a heating step of heating the precursor compound in the presence of the salt at a temperature of 500° C. or less. The production method of the present invention is advantageous in that it does not require high temperatures.

[0114] The heating step can be carried out in an inert gas atmosphere such as argon, nitrogen, etc. Alternatively, the heating step may be carried out in air or under reduced pressure such as vacuum.

[0115] The heating temperature (calcination temperature) in the heating step is not particularly limited, and even at around room temperature, a metathesis reaction (topochemical reaction) may proceed immediately upon contact of the precursor compound with the salt. From the viewpoint of the ionic conductivity of magnesium ions or calcium ions, the heating temperature is preferably 250 to 500°C, more preferably 300 to 500°C, and even more preferably 350 to 500°C. In this case, the production method of the present invention is likely to be excellent in reaction rate and yield, and also likely to produce oxides that cannot be obtained by conventional solid-phase synthesis methods.

[0116] As the heating method, a wide range of heating methods used in known oxide manufacturing methods can be adopted.

[0117] The heating time in the heating step is not particularly limited, and is, for example, preferably 3 to 99 hours, more preferably 10 to 99 hours.

[0118] Furthermore, from the viewpoint of the ionic conductivity of magnesium ions or calcium ions, the heating step is preferably carried out under a pressure of less than 0.2 MPa, and more preferably under atmospheric pressure (about 0.1 MPa).

[0119] It is preferable that the precursor compound is thoroughly mixed with the salt before or during the heating step, in which case the production method of the present invention tends to be excellent in reaction rate and yield.

[0120] The fired product obtained after heating can be directly subjected to the washing step described below, or the fired product can be cooled once and then subjected to the washing step.

[0121] 1-5. Washing Step The production method of the present invention includes a washing step in which the fired product obtained after the heating is washed with a washing liquid containing a polar solvent.

[0122] The washing solution used in the washing step is not particularly limited as long as it contains a polar solvent that can dissolve the salt used in the production method of the present invention and the salt generated after the heating step. From the viewpoint of yield, it preferably contains at least one solvent selected from the group consisting of water, alcohols (e.g., methanol, ethanol, propanol, butanol, etc.), and aprotic polar solvents (e.g., N,N-dimethylformamide (DMF), acetone, 1,3-dimethyl-2-imidazolidinone, tetrahydrofuran (THF), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), acetonitrile (MeCN), hexamethylphosphoric triamide (HMPA), etc.).

[0123] From the viewpoint of yield, the temperature of the washing liquid is preferably from 20° C. to the boiling point of the polar solvent, and more preferably from 40° C. to the boiling point of the polar solvent.

[0124] Specifically, the cleaning liquid is preferably water (particularly hot distilled water), ethanol, or acetone.

[0125] The washing step can be carried out, for example, by stirring the baked product in a washing solution.

[0126] The washing time in the washing step is not particularly limited, and may be the time required to dissolve the salt used in the production method of the present invention and the salt produced after the heating step.

[0127] The shape of the composite oxide obtained after washing is not particularly limited, and any shape such as powder, granules, pellets, or fibers can be adopted.

[0128] 1-6. Drying Step The production method of the present invention may include a drying step of drying the final product obtained after the above washing.

[0129] As the drying method, a wide variety of drying methods used in known oxide manufacturing methods can be adopted. The drying step can be carried out, for example, by leaving the final product overnight in a vacuum dryer. After drying, the product can be re-fired, for example, by applying the heating step again. In this case, the crystallinity of the composite oxide can be further improved.

[0130] 2. Battery Materials The present invention can also provide battery materials (e.g., electrode materials, solid electrolyte materials, etc.) containing the above-described composite oxides. Such battery materials are advantageous in that they have excellent ionic conductivity of magnesium ions or calcium ions, which are carrier ions.

[0131] The composite oxide that can be used as the battery material of the present invention is not particularly limited, and examples thereof include XM ２ TeO ６ , or XM ２ TeO ６ [In each formula, X is Mg or Ca, and M is Fe, Mn, Mg, Ca, Co, Ni, Cu, or Zn.] Among them, from the viewpoint of ease of insertion / release and / or conduction of magnesium ions or calcium ions, compounds having an ilmenite-type crystal structure, such as Mg ３ TeO ６ A compound represented by the following formula is preferred.

[0132] The electrode material is preferably a positive electrode active material, more preferably a positive electrode active material for a magnesium battery or a calcium battery, and further preferably a positive electrode active material for a magnesium secondary battery or a calcium secondary battery. In this case, a secondary battery with higher safety, lower production costs, and higher energy density than conventional lithium secondary batteries can be provided.

[0133] When the composite oxide obtained by the production method of the present invention is used as a positive electrode active material, for example, the positive electrode active material, a conductive additive, and optionally a binder are mixed to obtain a positive electrode mixture, which is then applied to a positive electrode current collector to produce a positive electrode.

[0134] As the conductive additive, a wide variety of known conductive additives can be used, including, for example, carbon materials such as acetylene black, ketjen black, carbon nanotubes, carbon nanofibers, graphite, and coke. The shape of the conductive additive is not particularly limited, and can be, for example, powder.

[0135] As the binder, a wide variety of known binders can be used, including, for example, fluororesins such as polyvinylidene fluoride resin and polytetrafluoroethylene.

[0136] The material constituting the positive electrode current collector can be a wide variety of materials constituting known current collectors, such as aluminum, titanium, platinum, molybdenum, stainless steel, copper, etc. The shape of the positive electrode current collector is not particularly limited, and can be, for example, a porous body, a foil, a plate, or a mesh.

[0137] The solid electrolyte material is preferably a solid electrolyte for magnesium batteries or calcium batteries, and more preferably a solid electrolyte for magnesium secondary batteries or calcium secondary batteries. In this case, a secondary battery with higher safety, lower production costs, and higher energy density than conventional lithium secondary batteries can be provided. The solid electrolyte can be formed into a layer using, for example, a known binder.

[0138] The present invention can provide a magnesium battery or calcium battery (preferably a magnesium secondary battery or a calcium secondary battery) comprising the above-mentioned electrode material and the above-mentioned solid electrolyte material. The structure of the battery (secondary battery) can be constructed with reference to known magnesium batteries or calcium batteries. Specifically, known negative electrode materials and separators can be used, respectively. The battery obtained in this manner is advantageous in terms of high safety, low manufacturing cost, and high energy density compared to conventional lithium secondary batteries.

[0139] 3. Optical Material The present invention can also provide an optical material containing the above-described composite oxide. Such an optical material is advantageous in that it can be obtained by a simple low-temperature synthesis method and is preferably a novel material.

[0140] As the composite oxide that can be used as the optical material of the present invention, from the viewpoint of obtaining a light-emitting body or a phosphor that emits various luminescent colors, it is preferable to use a composite oxide having a crystal structure with a space group lacking centrosymmetricity. Specific examples of the composite oxide are not particularly limited, and include, for example, Ca ３.５ SbO ６ (especially perovskite type), Ca ２ ZnTeO ６ (especially perovskite type), CaZn ２ TeO ６ (especially ilmenite type), Mg ３ TeO ６ (especially vacant type), CaMg ２ TeO ６ (especially ilmenite type).

[0141] The optical material can be used for any application in the optical field without any particular limitation, for example, as a sealant for optical semiconductors, a protective film for optical semiconductor elements, a protective agent for light-reflecting films, etc.

[0142] The type and form of the optical material are not particularly limited, and may be, for example, a polarizing element, a light-emitting diode (LED) element, a semiconductor laser element, a photodiode element, a phototransistor element, a solid-state imaging element, a light-emitting element for a photocoupler, a light-receiving element, a prism, a lens, an optical waveguide, an optical fiber, an optical filter, an optical disk substrate, an organic EL, a touch panel, a laser, or the like.

[0143] 4. Magnetic Material The present invention can also provide a magnetic material containing the above-described composite oxide. Such a magnetic material is advantageous in that it can be obtained by a simple low-temperature synthesis method and is preferably a novel material.

[0144] The composite oxides that can be used as magnetic materials preferably have properties such as strong magnetic anisotropy, high magnetic dipole, low magnetic anisotropy energy barrier, moderate magnetic compliance, and magnetic anomaly. Specific examples of the composite oxides are not particularly limited, and include, for example, Mg ２ CoTeO ６ , Mg ２ CuTeO ６ , Mg ２ NiTeO ６ , MgCo ２ TeO ６ , MgNi ２ TeO ６ , MgCu ２ TeO ６ , CaCo ２ TeO ６ , CaNi ２ TeO ６ , and CaCu ２ TeO ６ etc.

[0145] The magnetic material is not particularly limited and can be used for any application in electromagnetism, for example, as a hard magnetic material, a soft magnetic material, or a magnetostrictive material.

[0146] The type and form of the magnetic material are not particularly limited, and may be, for example, a permanent magnet, a transformer, a motor, a magnetic tape, a magnetic disk, a sensor, a power source, a speaker, an actuator, an MRI, or the like.

[0147] EXAMPLES Hereinafter, examples and comparative examples will be shown to further clarify the features of the present invention, but the present invention is not limited to the following examples.

[0148] The raw materials used in the examples and comparative examples are as follows: ２ CO ３ : Manufactured by Rare Metallic Co., Ltd., purity 99.9% (3N) Na ２ CO ３ : Manufactured by Kishida Chemical Co., Ltd., purity 99.8% FeO: Manufactured by Wako Pure Chemical Industries, Ltd., purity 99.5% (2N Up) MnO: Manufactured by Kojundo Kagaku Kenkyusho Co., Ltd., purity 99.9% (3N) Mn ２ O ３ : Manufactured by Kojundo Kagaku Kenkyusho Co., Ltd., purity 99.9% (3N) MnC ２ O ４ CoO: Manufactured by Kishida Chemical Co., Ltd., purity 99.8%; CoC: Manufactured by Rare Metallic Co., Ltd., purity 99.9% (3N) ２ O ４ : Manufactured by Kojundo Kagaku Kenkyusho Co., Ltd., purity 99% (2N) NiC ２ O ４ ・2H ２ O: Manufactured by Kojundo Kagaku Kenkyusho Co., Ltd., purity 99.9% (3N) CuO: Manufactured by Kojundo Kagaku Kenkyusho Co., Ltd., purity 99.99% (4N) NH ４ H ２ P.O. ４ : Manufactured by Kishida Chemical Co., Ltd., purity 99% (2N) KH ２ P.O. ４ : Manufactured by Kishida Chemical Co., Ltd., purity 99.5% (2N Up) NiO: Manufactured by Kojundo Chemical Co., Ltd., purity 99.7% TeO ２ : Sigma-Aldrich, purity 99% MgO: Kishida Chemical Co., Ltd., purity 99.5% NiC ２ O ４ : Manufactured by Kojundo Kagaku, purity 99.9%) FeC ２ O ４ ・2H ２ O: Junsei Kagaku, purity 99.9% (3N) MgO: Manufactured by Kishida Chemical Co., Ltd., purity 99% TeO ２: Manufactured by Kishida Chemical Co., Ltd., purity 99+% CuO: Manufactured by Kishida Chemical Co., Ltd., purity 99% ZnO: Manufactured by Kishida Chemical Co., Ltd., purity 99.5% Sb ２ O ５ :High Purity Chemical Research Institute Bi ２ O ３ : manufactured by Kishida Chemical Co., Ltd. CaO: manufactured by Kishida Chemical Co., Ltd., purity 98% GeO ２ : Sigma-Aldrich Li ２ CO ３ : High Purity Chemical Research Institute, 99% pure MgCl ２ : Sigma-Aldrich Mg(NO ３ ) ２ ・6H ２ O: MgSO manufactured by Kishida Chemical Co., Ltd. ４ : Kishida Chemical Co., Ltd. Ca(NO ３ ) ２ ・4H ２ O: CaCl manufactured by Sigma-Aldrich ２ ・2H ２ O: RuO manufactured by Kishida Chemical Co., Ltd. ２ : SiO manufactured by Sigma-Aldrich ２ : Manufactured by Kishida Chemical Co., Ltd., precipitated ammonia water (28%): Manufactured by Kishida Chemical Co., Ltd. BaCO ３ : Manufactured by Kishida Chemical Co., Ltd., purity 99.9% TiO ２ : Manufactured by Kishida Chemical Co., Ltd., sedimentation

[0149] [Powder X-ray Diffraction (XRD) Measurement] Identification of the synthesized samples and collection of data for structural analysis were performed by X-ray diffraction measurement using an X-ray diffractometer D2 PHASER (manufactured by Bruker Corporation). CuKα monochromated by a monochromator was used as the X-ray source. The measurement conditions were a tube voltage of 50 kV and a tube current of 300 mA. At this time, the scanning speed was set so that the intensity was approximately 10,000 counts. The samples used for measurement were sufficiently pulverized to obtain uniform particles.

[0150] [Production Examples 1 to 5: Precursor compound Li ４ MTeO ６ (M=Cu, Co, Zn, Mg, Ni) Synthesis Example 1: Li ４ NiTeO６ ) Li as raw material powder ２ CO ３ , NiO and TeO ２ These raw material powders were used. ２ CO ３ :NiO:TeO ２ The starting materials were weighed out so that the molar ratio was 2:1:1, and mixed in an agate mortar for about 30 minutes to obtain the starting material. The starting materials were molded into pellets, and the resulting molded bodies were heat-treated in an electric furnace in air at a firing temperature of 800°C for 20 hours to obtain the product. XRD measurement and analysis showed that the resulting product contained Li ４ NiTeO ６ It was confirmed that this was the case (Figure 1).

[0151] (Production example 2: Li ４ CoTeO ６ The same procedure as in Production Example 1 was carried out, except that CoO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Li ４ CoTeO ６ It was confirmed that this was the case (Figure 1).

[0152] (Production example 3: Li ４ CuTeO ６ The same procedure as in Production Example 1 was carried out, except that CuO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Li ４ CuTeO ６ It was confirmed that this was the case (Figure 1).

[0153] (Production example 4: Li ４ MgTeO ６ The same procedure as in Production Example 1 was carried out, except that MgO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Li ４ MgTeO ６ It was confirmed that this was the case (Figure 1).

[0154] (Production example 5: Li ４ ZnTeO ６ The same procedure as in Production Example 1 was carried out, except that ZnO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Li ４ ZnTeO ６It was confirmed that this was the case (Figure 1).

[0155] [Production Examples 6 to 11c: Precursor compound Na ４ MTeO ６ (M=Zn, Mg, Co, Cu, Ni, Ca, Fe, Mn) (Production Example 6: Na ４ NiTeO ６ ) Li ２ CO ３ Instead of Na ２ CO ３ The same procedure as in Production Example 1 was carried out except that Na was used. ４ NiTeO ６ It was confirmed that this was the case (Figure 2).

[0156] (Production Example 7: Na ４ CoTeO ６ The same procedure as in Production Example 6 was carried out, except that CoO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ４ CoTeO ６ It was confirmed that this was the case (Figure 2).

[0157] (Production Example 8: Na ４ CuTeO ６ The same procedure as in Production Example 6 was carried out, except that CuO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ４ CuTeO ６ It was confirmed that this was the case (Figure 2).

[0158] (Production Example 9: Na ４ MgTeO ６ The same procedure as in Production Example 6 was carried out, except that MgO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ４ MgTeO ６ It was confirmed that the obtained Na ４ MgTeO ６ is a novel compound that has not been described in the literature.

[0159] (Production Example 10: Na ４ ZnTeO ６The same procedure as in Production Example 6 was carried out, except that ZnO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ４ ZnTeO ６ It was confirmed that this was the case (Figure 2).

[0160] (Production Example 11a: Na ４ CaTeO ６ The same procedure as in Production Example 6 was carried out, except that CaO was used instead of NiO, the firing temperature was 840°C, and the firing time was 99 hours. XRD measurement and analysis revealed that the obtained product contained Na ４ CaTeO ６ It was confirmed that the obtained Na ４ CaTeO ６ is a novel compound that has not been described in the literature.

[0161] (Production Example 11b: Na ４ FeTeO ６ The same procedure as in Production Example 6 was carried out, except that FeO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ４ FeTeO ６ It was confirmed that this is the case.

[0162] (Production Example 11c: Na ４ MnTeO ６ The same procedure as in Production Example 6 was carried out, except that MnO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ４ MnTeO ６ It was confirmed that this is the case.

[0163] [Production Examples 12 to 16: Precursor compound Li ２ M ２ TeO ６ (M = Ni ０．５ Co ０．５ , Zn, Cu, Co, Mg, Ni)] (Production Example 12: Li ２ Ni ２ TeO ６ ) The raw material powder is Li ２ CO ３ :NiO:TeO ２The same operation as in Production Example 1 was carried out, except that the amounts were weighed out so that the molar ratio was 1:2:1. XRD measurement and analysis showed that the obtained product contained Li ２ Ni ２ TeO ６ It was confirmed that this was the case (Figure 3).

[0164] (Production Example 13: Li ２ Co ２ TeO ６ The same procedure as in Production Example 12 was carried out, except that CoO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Li ２ Co ２ TeO ６ It was confirmed that this was the case (Figure 3).

[0165] (Production Example 14: Li ２ Cu ２ TeO ６ The same procedure as in Production Example 12 was carried out, except that CuO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Li ２ Cu ２ TeO ６ It was confirmed that this was the case (Figure 3).

[0166] (Production Example 15: Li ２ Mg ２ TeO ６ The same procedure as in Production Example 12 was carried out, except that MgO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Li ２ Mg ２ TeO ６ It was confirmed that this was the case (Figure 3).

[0167] (Production Example 16: Li ２ Zn ２ TeO ６ The same procedure as in Production Example 12 was carried out, except that ZnO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Li ２ Zn ２ TeO ６ It was confirmed that the obtained Li ２ Zn ２ TeO ６ is a novel compound that has not been described in the literature.

[0168] [Production Examples 17 to 21: Precursor compound Na ２ M ２ TeO ６ (M = Ni ０．５ Co ０．５ , Zn, Cu, Co, Mg, Ni)] (Production Example 17: Na ２ Ni ２ TeO ６ ) Li ２ CO ３ Instead of Na ２ CO ３ The same procedure as in Production Example 12 was carried out except that Na was used. ２ Ni ２ TeO ６ It was confirmed that this was the case (Figure 4).

[0169] (Production Example 18: Na ２ Co ２ TeO ６ The same procedure as in Production Example 17 was carried out, except that CoO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ２ Co ２ TeO ６ It was confirmed that this was the case (Figure 4).

[0170] (Production Example 19: Na ２ Cu ２ TeO ６ The same procedure as in Production Example 17 was carried out, except that CuO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ２ Cu ２ TeO ６ It was confirmed that this was the case (Figure 4).

[0171] (Production Example 20: Na ２ Mg ２ TeO ６ The same procedure as in Production Example 17 was carried out, except that MgO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ２ Mg ２ TeO ６ It was confirmed that this was the case (Figure 4).

[0172] (Production Example 21: Na ２ Zn ２ TeO ６ The same procedure as in Production Example 17 was carried out, except that ZnO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ２ Zn ２ TeO ６ It was confirmed that this was the case (Figure 4).

[0173] [Production Example 22: Precursor compound BaNi ２ TeO ６ Synthesis of BaNi ２ TeO ６ ) BaCO as raw material powder ３ , NiO and TeO ２ These raw material powders were mixed with BaCO ３ :NiO:TeO ２ The starting materials were weighed out so that the molar ratio was 1:2:1, and mixed in an agate mortar for about 30 minutes to obtain the starting material. The starting materials were molded into pellets, and the resulting molded bodies were heat-treated in an electric furnace in air at a firing temperature of 840°C for 99 hours to obtain the product. XRD measurement and analysis showed that the resulting product was BaNi ２ TeO ６ It was confirmed that this is the case.

[0174] [Production Examples 23 to 27: Precursor compound Na ３ M １．５ TeO ６ (M=Zn, Mg, Cu, Co, Ni) (Production Example 23: Na ３ Ni １．５ TeO ６ ) Na as raw material powder ２ CO ３ , NiO and TeO ２ These raw material powders were mixed with Na ２ CO ３ :NiO:TeO ２ The starting materials were weighed out so that the molar ratio was 1.5:1.5:1, and mixed in an agate mortar for about 30 minutes to obtain the starting material. The starting materials were molded into pellets, and the resulting molded bodies were heat-treated in an electric furnace in air at a firing temperature of 950°C for 24 hours to obtain the product. XRD measurement and analysis showed that the resulting product contained Na３ Ni １．５ TeO ６ It was confirmed that this was the case (Figure 5).

[0175] (Production Example 24: Na ３ Co １．５ TeO ６ The same procedure as in Production Example 22 was carried out, except that CoO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ３ Co １．５ TeO ６ It was confirmed that the obtained Na ３ Co １．５ TeO ６ is a novel compound that has not been described in the literature.

[0176] (Production Example 25: Na ３ Cu １．５ TeO ６ The same procedure as in Production Example 22 was carried out, except that CuO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ３ Cu １．５ TeO ６ It was confirmed that the obtained Na ３ Cu １．５ TeO ６ is a novel compound that has not been described in the literature.

[0177] (Production Example 26: Na ３ Mg １．５ TeO ６ The same procedure as in Production Example 22 was carried out, except that MgO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ３ Mg １．５ TeO ６ It was confirmed that the obtained Na ３ Mg １．５ TeO ６ is a novel compound that has not been described in the literature.

[0178] (Production Example 27: Na ３ Zn １．５ TeO ６ The same procedure as in Production Example 22 was carried out, except that ZnO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na３ Zn １．５ TeO ６ It was confirmed that the obtained Na ３ Zn １．５ TeO ６ is a novel compound that has not been described in the literature.

[0179] [Production Examples 28 to 30: Precursor compound Na ３ M ２ RuO ６ (M=Co, Mg, Ni) Synthesis] (Production Example 28: Na ３ Ni ２ RuO ６ ) Na as raw material powder ２ CO ３ , NiO and RuO ２ These raw material powders were mixed with Na ２ CO ３ :NiO:RuO ２ The starting materials were weighed out so that the molar ratio was 1.5:2:1, and mixed in an agate mortar for about 30 minutes to obtain the starting material. The starting materials were molded into pellets, and the resulting molded bodies were heat-treated in an electric furnace in air at a firing temperature of 800°C for 20 hours to obtain the product. XRD measurement and analysis revealed that the resulting product contained Na ３ Ni ２ RuO ６ It was confirmed that this was the case (Figure 6).

[0180] (Production Example 29: Na ３ Co ２ RuO ６ The same procedure as in Production Example 27 was carried out, except that CoO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ３ Co ２ RuO ６ It was confirmed that the obtained Na ３ Co ２ RuO ６ is a novel compound that has not been described in the literature.

[0181] (Production Example 30: Na ３ Mg ２ RuO ６The same procedure as in Production Example 27 was carried out, except that MgO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ３ Mg ２ RuO ６ It was confirmed that the obtained Na ３ Mg ２ RuO ６ is a novel compound that has not been described in the literature.

[0182] [Production Examples 31 to 33: Precursor compound Na ３ M ２ Bio ６ (M=Ni, Co, Ni ０．５ Co ０．５ Synthesis of Na ３ Ni ２ Bio ６ ) Na as raw material powder ２ CO ３ , NiO and Bi ２ O ３ These raw material powders were mixed with Na ２ CO ３ :NiO:Bi ２ O ３ The starting materials were weighed out so that the molar ratio was 1.5:2:0.5, and mixed in an agate mortar for about 30 minutes to obtain the starting material. The starting materials were molded into pellets, and the resulting molded bodies were heat-treated in an electric furnace in air at a firing temperature of 800°C for 20 hours to obtain the product. XRD measurement and analysis revealed that the resulting product contained Na ３ Ni ２ Bio ６ It was confirmed that this was the case (Figure 7).

[0183] (Production Example 32: Na ３ Co ２ Bio ６ The same procedure as in Production Example 30 was carried out, except that CoO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ３ Co ２ Bio ６ It was confirmed that the obtained Na ３ Co ２ Bio ６ is a novel compound that has not been described in the literature.

[0184] (Production Example 33: Na ３ NiCoBiO ６ The same procedure as in Production Example 30 was carried out, except that NiO and CoO were used in a molar ratio of 1:1 instead of NiO. XRD measurement and analysis revealed that the resulting product contained Na ３ NiCoBiO ６ It was confirmed that the obtained Na ３ NiCoBiO ６ is a novel compound that has not been described in the literature.

[0185] [Production Examples 34 to 36b: Precursor compound Na ３ M ２ SbO ６ (M=Ni, Co, Ni ０．５ Co ０．５ , Ni １／６ Co １／６ Zn １／６ Mg １／６ Cu １／６ Mn １／６ Synthesis of Na ３ Ni ２ SbO ６ ) Na as raw material powder ２ CO ３ , NiO and Sb ２ O ５ These raw material powders were mixed with Na ２ CO ３ :NiO:Sb ２ O ５ The starting materials were weighed out so that the molar ratio was 1.5:2:0.5, and mixed in an agate mortar for about 30 minutes to obtain the starting material. The starting materials were molded into pellets, and the resulting molded bodies were heat-treated in an electric furnace in air at a firing temperature of 800°C for 20 hours to obtain a product. XRD measurement and analysis of the obtained product using the equipment and conditions shown below revealed that the product contained Na. ３ Ni ２ SbO ６ It was confirmed that this was the case (Figure 8).

[0186] (Production Example 35: Na ３ Co ２ SbO ６The same procedure as in Production Example 34 was carried out, except that CoO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Na ３ Co ２ SbO ６ It was confirmed that this was the case (Figure 8).

[0187] (Production Example 36a: Na ３ NiCoSbO ６ The same procedure as in Production Example 34 was carried out, except that NiO and CoO were used in a molar ratio of 1:1 instead of NiO. XRD measurement and analysis revealed that the resulting product contained Na ３ NiCoSbO ６ It was confirmed that the obtained Na ３ NiCoSbO ６ is a novel compound that has not been described in the literature.

[0188] (Production Example 36b: Na ３ Ni １／３ Co １／３ Zn １／３ Mg １／３ Cu １／３ Mn １／３ SbO ６ The same procedure as in Production Example 34 was carried out, except that NiO was replaced with NiO, CoO, ZnO, MgO, CuO, and MnO in a molar ratio of 1:1:1:1:1:1. XRD measurement and analysis revealed that the resulting product was Na ３ Ni １／３ Co １／３ Zn １／３ Mg １／３ Cu １／３ Mn １／３ SbO ６ It was confirmed that this is the case.

[0189] (Production Example 37: Na ３ Ca ２ SbO ６ The same procedure as in Production Example 34 was carried out, except that CaO was used instead of NiO, the firing temperature was 1050°C, and the firing time was 24 hours. XRD measurement and analysis showed that the obtained product contained Na ３ Ca ２ SbO ６ It was confirmed that the obtained Na３ Ca ２ SbO ６ is a novel compound that has not been described in the literature.

[0190] [Production Example 38: Precursor compound Na ４ CaTeO ６ Synthesis of Na ４ CaTeO ６ ) Na as raw material powder ２ CO ３ , CaO and TeO ２ These raw material powders were mixed with Na ２ CO ３ :CaO:TeO ２ The starting materials were weighed out so that the molar ratio was 2:1:1, and mixed in an agate mortar for about 30 minutes to obtain the starting material. The starting materials were molded into pellets, and the resulting molded bodies were heat-treated in an electric furnace in air at a firing temperature of 800°C for 20 hours to obtain a product. XRD measurement and analysis of the obtained product using the equipment and conditions shown below revealed that the product contained Na. ５ CaTeO ６ It was confirmed that this was the case (Figure 8).

[0191] [Production Examples 39 to 41, 42a and 42b: Precursor Compound K ２ FeDO ４ (D=Si, Ti, Ge), precursor compound K ２ CaSiO ４ and precursor compound K ２ MgSiO ４ Synthesis of Production Example 39: K ２ FeSiO ４ ) K ２ CO ３ To prevent water absorption, the synthesis work was carried out in a dry room (same below). ２ CO ３ , FeC ２ O ４ ・2H ２ O and SiO ２ These raw material powders were used. ２ CO ３ : FeC ２ O ４ ・2H ２ O:SiO ２The starting materials were weighed out so that the molar ratio was 1:1:1, and mixed in an agate mortar for about 30 minutes to obtain the starting materials. Thereafter, the starting materials were placed in a chrome steel container together with zirconia balls (15 mmΦ x 20 pieces), acetone was added, and the mixture was pulverized and mixed for 6 hours at 400 rpm in a planetary ball mill (Fritsch; P-7). After that, the acetone was distilled off under reduced pressure, and the recovered powder was pelletized at 40 MPa and fired for 3 hours at a firing temperature of 800 ° C under an Ar stream. The heating rate was 400 ° C / h. The cooling rate was 100 ° C / h up to 300 ° C, and thereafter the mixture was allowed to cool to room temperature by natural cooling. The product obtained after firing was brought into a glove box maintained in an Ar atmosphere and stored in an environment without contact with air. XRD measurement and analysis showed that the obtained product was K ２ FeSiO ４ It was confirmed that this was the case (Figure 9).

[0192] (Production example 40: K ２ FeTiO ４ ) SiO ２ Instead of TiO ２ The same procedure as in Production Example 39 was carried out except that K was used. ２ FeTiO ４ It was confirmed that this was the case (Figure 9).

[0193] (Production example 41: K ２ FeGeO ４ ) SiO ２ Instead of GeO ２ The same procedure as in Production Example 39 was carried out except that K was used. ２ FeGeO ４ It was confirmed that this was the case (Figure 9).

[0194] (Production example 42a: K ２ CaSiO ４ ) FeC ２ O ４ ・2H ２ The same procedure as in Production Example 39 was carried out, except that CaO was used instead of O. XRD measurement and analysis showed that the obtained product was K ２ CaSiO ４ It was confirmed that this was the case (Figure 9).

[0195] (Production example 42b: K ２ MgSiO ４ ) FeC ２ O ４ ・2H ２ The same procedure as in Production Example 42a was carried out, except that MgO was used instead of O. XRD measurement and analysis showed that the obtained product was K ２ MgSiO ４ It was confirmed that this is the case.

[0196] [Production Examples 43 to 46: Precursor compound K ２ MP ２ O ７ Synthesis of (M=Cu, Ni, Co, Mn)] (Production Example 43: K ２ CuP ２ O ７ ) K as raw material powder ２ CO ３ , CuO and NH ４ H ２ P.O. ４ These raw material powders were weighed out so that the potassium:copper:phosphorus ratio (molar ratio) was 1:1:2, and mixed in an agate mortar for approximately 30 minutes. The mixture was molded into pellets and fired in an electric furnace in Ar at a firing temperature of 650°C for 30 hours. The product obtained after firing was brought into a glove box maintained in an Ar atmosphere and stored in an environment without contact with air. XRD measurement and analysis showed that the product obtained was K ２ CuP ２ O ７ It was confirmed that this was the case (Figure 10).

[0197] (Production example 44: K ２ MnP ２ O ７ The same procedure as in Production Example 39 was carried out, except that MnO was used instead of CuO and the raw material powder was weighed out so that the potassium:manganese:phosphorus ratio (molar ratio) was 1:1:2. XRD measurement and analysis revealed that the obtained product was K ２ CaSiO ４ It was confirmed that this was the case (Figure 10).

[0198] (Production example 45: K ２ CoP ２ O７ ) CoC instead of CuO ２ O ４ The same operations as in Production Example 39 were carried out, except that the raw material powders were weighed out so that the potassium:cobalt:phosphorus ratio (molar ratio) was 1:1:2, and the firing time was 20 hours. ２ CaSiO ４ It was confirmed that this was the case (Figure 10).

[0199] (Production example 46: K ２ NiP ２ O ７ ) CoC ２ O ４ Instead of NiC ２ O ４ ・2H ２ The same operation as in Production Example 45 was carried out, except that O was used and the raw material powder was weighed out so that the potassium:nickel:phosphorus ratio (molar ratio) was 1:1:2. ２ CaSiO ４ It was confirmed that the obtained K ２ CaSiO ４ had an XRD pattern different from that previously reported.

[0200] [Example 1: Production of magnesium composite oxide] In a glove box, the precursor compound obtained in the above Production Example and MgCl ２ The two compounds were weighed out to a molar ratio of 1:4 and mixed in a mortar for 1 hour. The total amount was adjusted to 2 g. After mixing, the mixture was placed in a glove box (porcelain crucible) and fired at 400°C for 10 to 99 hours under an Ar or air atmosphere to allow the topochemical ion exchange reaction to proceed. The resulting product was then vigorously stirred with a magnetic stirrer in hot distilled water to remove the residual MgCl. ２ After dissolving the magnesium oxide and other salts, the mixture was filtered and finally dried overnight in an oven at 80°C. The powder was recovered from the container in a glove box to obtain the target magnesium composite oxide. The obtained magnesium composite oxide and the precursor compound used are shown in Table 1, along with their crystal structures.

[0201]

[0202] Among the magnesium composite oxides obtained in Example 1, MgM ２ TeO ６ , and Mg １．５ M' ２ Bio ６ (M=Zn, Mg, Co, Cu, Ni; M'=Ni, Co, Ni ０．５ Co ０．５ ) is a novel compound that has not been described in the literature.

[0203] XRD patterns of the magnesium composite oxides obtained in the examples are shown in Figures 11 to 14. These XRD patterns confirmed that the desired magnesium composite oxides were obtained in each example. Furthermore, it was confirmed that the production method of the present invention allows the cations constituting the precursor compound to be replaced with magnesium ions through a topochemical ion exchange reaction, thereby obtaining the corresponding magnesium composite oxide.

[0204] Photographs of the precursor compounds obtained in the Production Examples (top row) and the magnesium composite oxides obtained in the Examples (middle row) and the Comparative Examples (bottom row) described below are shown in Figures 15 and 16, and the colors of each compound are shown in Table 2. These photographs confirm that some of the magnesium composite oxides obtained by the production method of the present invention exhibit a color different from that of the corresponding precursor compounds. Furthermore, a comparison of the magnesium composite oxides of the Examples with the magnesium composite oxides of the Comparative Examples having the same chemical composition confirms that some of the magnesium composite oxides obtained by the production method of the present invention exhibit a color different from that of the magnesium composite oxides obtained by conventional methods. These results suggest that the production method of the present invention can produce magnesium composite oxides having a crystal structure different from the high-temperature / high-pressure phase obtained by conventional methods, particularly a crystal structure containing defects and distortions. In this way, the production method of the present invention can provide novel magnesium composite oxides and production methods thereof.

[0205]

[0206] Magnesium composite oxides Mg obtained in Examples 1-14, 1-4 and 1-9 ３ TeO ６ The polymorphic crystal structures (polyhedral model and atomic model) of the magnesium composite oxides are shown in Figure 17. The XRD patterns of these are also shown in Figure 18. The production method of the present invention can obtain magnesium composite oxides having a crystal structure corresponding to the precursor compound used. Therefore, the production method of the present invention can provide magnesium composite oxides having a variety of crystal structures, particularly magnesium composite oxides having novel crystal structures. Furthermore, the production method of the present invention can provide magnesium composite oxides, which have previously only been obtainable under high temperature and high pressure, in a simple manner.

[0207] 19 and 20 show the XRD patterns of the magnesium composite oxides of Examples 1-6, 1-7, and 1-10 to 1-13, and the XRD pattern of the magnesium composite oxide obtained by a conventional method, respectively. In each figure, the two magnesium composite oxides have substantially the same composition. These results confirm that the magnesium composite oxide obtained by the production method of the present invention has a different crystal structure from that obtained by a conventional method, despite having the same or similar composition.

[0208] Ilmenite-type Mg obtained in Examples 1-9 ３ TeO ６ The results of the ionic conductivity plot are shown in Figure 25. The magnesium composite oxide obtained by the production method of the present invention exhibited higher ionic conductivity than conventional magnesium ion conductors. Therefore, the magnesium composite oxide obtained by the production method of the present invention may be useful as a battery material such as a cathode material or a solid electrolyte.

[0209] The magnesium composite oxides obtained in the examples were nanoparticles with an average particle size in the range of 10 nm to 100 nm. The average particle size of the magnesium composite oxides was evaluated using an ultra-high resolution scanning electron microscope. A further advantage of the present invention is that the low temperature conditions of metathesis synthesis make it possible to easily obtain nanoparticles immediately after nucleation and before significant crystal growth occurs. This is in contrast to conventional solid-state synthesis, where the high reaction temperatures tend to cause Ostwald ripening during crystal growth and particle coarsening, resulting in large particle sizes.

[0210] [Comparative Examples 1 to 5: Conventional MgM ２ TeO ６ (M = Cu, Zn, Mg, Co, Ni) solid phase synthesis] (Comparative Example 1: MgNi ２ TeO ６ ) MgO, NiO and TeO as raw material powders ２ These raw material powders were mixed in the following order: MgO:NiO:TeO ２ The starting materials were weighed out so that the molar ratio was 1:2:1, and mixed in an agate mortar for about 30 minutes to obtain the starting material. The starting materials were molded into pellets, and the resulting molded bodies were heat-treated in an electric furnace in air at a firing temperature of 840°C for 99 hours to obtain the product. XRD measurement and analysis showed that the resulting product was MgNi ２ TeO ６ It was confirmed that the obtained MgNi ２ TeO ６ is a novel compound that has not been described in the literature.

[0211] (Comparative Example 2: MgCo ２ TeO ６ The same procedure as in Comparative Example 1 was carried out except that CoO was used instead of NiO. XRD measurement and analysis revealed that the obtained product was MgCo ２ TeO ６ It was confirmed that the obtained MgCo ２ TeO ６ is a novel compound that has not been described in the literature.

[0212] (Comparative example 3: MgCu ２ TeO ６The same procedure as in Comparative Example 1 was carried out except that CuO was used instead of NiO. XRD measurement and analysis revealed that the obtained product was MgCu ２ TeO ６ It was confirmed that the obtained MgCu ２ TeO ６ is a novel compound that has not been described in the literature.

[0213] (Comparative example 4: Mg ３ TeO ６ The same procedure as in Comparative Example 1 was carried out except that MgO was used instead of NiO. XRD measurement and analysis showed that the obtained product contained Mg ３ TeO ６ It was confirmed that this was the case (Figure 26).

[0214] (Comparative Example 5: MgZn ２ TeO ６ The same procedure as in Comparative Example 1 was carried out except that ZnO was used instead of NiO. XRD measurement and analysis showed that the obtained product was MgZn ２ TeO ６ It was confirmed that the obtained MgZn ２ TeO ６ is a novel compound that has not been described in the literature.

[0215] [Comparative Examples 6 to 10: Conventional MgM ２ TeO ６ (M=Cu, Zn, Mg, Co, Ni) solid-phase synthesis] (Comparative Example 6: Mg ２ NiTeO ６ ) MgO, NiO and TeO as raw material powders ２ These raw material powders were mixed in the following order: MgO:NiO:TeO ２ The starting materials were weighed out so that the molar ratio was 2:1:1, and mixed in an agate mortar for about 30 minutes to obtain the starting material. The starting materials were molded into pellets, and the resulting molded bodies were heat-treated in an electric furnace in air at a firing temperature of 840°C for 99 hours to obtain the product. XRD measurement and analysis showed that the resulting product contained Mg ２ NiTeO ６ It was confirmed that this was the case (Figure 27).

[0216] (Comparative Example 7: Mg ２CoTeO ６ The same procedure as in Comparative Example 6 was carried out, except that CoO was used instead of NiO. XRD measurement and analysis revealed that the obtained product was MgCo ２ TeO ６ It was confirmed that this was the case (Figure 27).

[0217] (Comparative Example 8: Mg ２ CuTeO ６ The same procedure as in Comparative Example 6 was carried out except that CuO was used instead of NiO. XRD measurement and analysis revealed that the obtained product was MgCu ２ TeO ６ It was confirmed that this was the case (Figure 27).

[0218] (Comparative Example 9: Mg ３ TeO ６ The same procedure as in Comparative Example 6 was carried out except that MgO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Mg ３ TeO ６ It was confirmed that this was the case (Figure 27).

[0219] (Comparative Example 10: Mg ２ ZnTeO ６ The same procedure as in Comparative Example 6 was carried out except that ZnO was used instead of NiO. XRD measurement and analysis revealed that the obtained product contained Mg ２ ZnTeO ６ It was confirmed that this was the case (Figure 27).

[0220] The XRD patterns of the magnesium composite oxides obtained in Comparative Examples 1 to 10 were confirmed to have a crystal structure known as a high-temperature, high-pressure phase. The crystal structures of Comparative Examples 1 to 10 are shown in Table 3.

[0221]

[0222] The magnesium composite oxide obtained in the comparative example was obtained as a coarse powder having an average particle size of 1 μm or more.

[0223] [Example 2: Production of calcium composite oxide] In a glove box, the precursor compound obtained in the above Production Example and Ca(NO ３ ) ２ ・4H２ O were weighed out to a molar ratio of 1:2, and then mixed in a mortar for 1 hour. The total amount was adjusted to 2 g. After mixing, the mixture was placed in a glove box (porcelain crucible) and fired at 500°C for 10 to 99 hours under an Ar atmosphere or an air atmosphere to allow the topochemical ion exchange reaction / metathesis reaction to proceed. The resulting product was then vigorously stirred with a magnetic stirrer in hot distilled water to remove the residual Ca(NO ３ ) ２ ・4H ２ After dissolving the O and other salts, the mixture was filtered and finally dried overnight in an oven at 80°C. The powder was recovered from the container in a glove box to obtain the target calcium composite oxide. The obtained calcium composite oxide and the precursor compound used are shown in Table 4, along with their crystal structures.

[0224]

[0225] Of the calcium composite oxides obtained in Example 2, Ca ２ MTeO ６ (M=Zn, Cu), CaM ２ TeO ６ (M=Zn, Mg, Co, Cu, Ni), Ca １．５ M ２ Bio ６ , Ca １．５ M ２ SbO ６ , Ca １．５ M ２ RuO ６ (M=Ni, Co, Ni ０．５ Co ０．５ ), Ca ３．５ SbO ６ , CaFeTiO ４ , and CaFeGeO ４ is a novel compound that has not been described in the literature.

[0226] The XRD patterns of the calcium composite oxides obtained in the examples are shown in Figures 28 to 32. These XRD patterns confirmed that the desired calcium composite oxides were obtained in each example. Furthermore, it was confirmed that the production method of the present invention allows the cations constituting the precursor compound to be replaced with calcium ions through a topochemical ion exchange reaction, thereby obtaining the corresponding calcium composite oxide.

[0227] Photographs of the precursor compounds obtained in the Production Examples (top row) and the calcium composite oxides obtained in the Examples (bottom row) are shown in Figures 34 and 35, and the colors of each compound are shown in Table 5. It was confirmed from the photographs that some of the calcium composite oxides obtained by the production method of the present invention exhibited colors different from those of the corresponding precursor compounds. Thus, the production method of the present invention can provide novel calcium composite oxides and production methods thereof.

[0228]

[0229] The polymorphism of the crystal structure (polyhedron model) of the calcium composite oxide obtained in Example 2 is shown in Figure 36. The production method of the present invention produces calcium composite oxides having a crystal structure corresponding to the precursor compound used. Therefore, the production method of the present invention can provide calcium composite oxides having a variety of crystal structures, particularly calcium composite oxides having novel crystal structures. Furthermore, the production method of the present invention can provide calcium composite oxides, which have previously only been obtainable under high temperature and high pressure, in a simple manner.

[0230] The calcium composite oxide obtained in this example was nanoparticles with an average particle size in the range of 10 nm to 100 nm. The average particle size of the calcium composite oxide was evaluated using an ultra-high-resolution scanning electron microscope. Another advantage of the present invention is that the low-temperature conditions of metathesis synthesis make it possible to easily obtain nanoparticles immediately after nucleation and before significant crystal growth occurs. This is in contrast to conventional solid-state synthesis, where the high reaction temperatures tend to cause Ostwald ripening during crystal growth and particle coarsening, resulting in large particle sizes.

[0231] [Example 3: Production of magnesium composite oxide] In a glove box, the precursor compound obtained in Production Example 9 and MgSO ４ The two compounds were weighed out to a molar ratio of 1:1 and mixed in a mortar for 1 hour. The total amount was adjusted to 2 g. After mixing, the mixture was baked in a glove box (porcelain crucible) in vacuum at 400°C for 99 hours to allow a topochemical ion exchange reaction to proceed. The resulting product was then vigorously stirred with a magnetic stirrer in hot distilled water, and then similarly stirred in acetone to remove the residual MgSO . ４ After dissolving the magnesium stearate and other salts, the mixture was filtered and finally dried overnight in an oven at 100°C. The powder was collected from the container in a glove box to obtain the target magnesium composite oxide. The XRD pattern of the obtained magnesium composite oxide was compared with that of the ilmenite-type magnesium oxide calculated by simulation. ３ TeO ６ The crystal structures of the obtained magnesium composite oxide and precursor compound are shown in Table 6.

[0232]

[0233] [Example 4: Production of magnesium composite oxide] In a glove box, the precursor compounds obtained in Production Examples 28 to 37 and Mg(NO ３ ) ２ ・6H ２ O were weighed out to a molar ratio of 1:2, and then mixed in a mortar for 1 hour. The total amount was adjusted to 2 g. After mixing, the mixture was baked in a glove box (porcelain crucible) under a nitrogen atmosphere at 250°C for 99 hours to allow a topochemical ion exchange reaction to proceed. The resulting product was then vigorously stirred with a magnetic stirrer in hot distilled water, and then similarly stirred in acetone to remove the residual Mg(NO ３ ) ２ ・6H ２After dissolving the O and other salts, the mixture was filtered and finally dried overnight in an oven at 100°C. The powder was collected from the container in a glove box to obtain the target magnesium composite oxide. The XRD patterns of the obtained magnesium composite oxide are shown in Figures 39 and 40. The crystal structures of the obtained magnesium composite oxide and precursor compound are shown in Table 7. １．５ Ni ２ RuO ６ , Mg １．５ Co ２ RuO ６ , Mg ３．５ RuO ６ , Mg １．５ Ni ２ SbO ６ , Mg １．５ Co ２ SbO ６ , Mg １．５ NiCoSbO ６ , Mg １．５ Ni ２ SbBiO ６ , Mg １．５ Co ２ Bio ６ , and Mg １．５ NiCoBiO ６ ) are all novel compounds not previously described in the literature.

[0234]

[0235] [Example 5: Production of calcium composite oxide] In a glove box, the precursor compound Na obtained in Production Example 9 was ４ MgTeO ６ and CaCl ２ ・2H ２ O or Ca(NO ３ ) ２ ・4H ２ O were weighed out to a molar ratio of 1:2, and then mixed in a mortar for 1 hour. The total amount was adjusted to 2 g. After mixing, the mixture was placed in a glove box (porcelain crucible) and fired at 500°C for 99 hours under a nitrogen atmosphere to allow the topochemical ion exchange reaction / metathesis reaction to proceed. The resulting product was then vigorously stirred in ethanol with a magnetic stirrer to remove the residual CaCl. ２・2H ２ O or Ca(NO ３ ) ２ ・4H ２ After dissolving the O and other salts, the mixture was filtered and finally dried overnight in an oven at 100°C. The powder was collected from the container in a glove box to obtain the target calcium composite oxide. The XRD pattern of the obtained calcium composite oxide was compared with that of the perovskite-type Ca ２ MgTeO ６ The crystal structure of the obtained calcium composite oxide, the salt used, and the precursor compound are shown in Table 8.

[0236]

[0237] [Example 6: Production of calcium composite oxide] In a glove box, the precursor compound K obtained in Production Example 42b was ２ MgSiO ４ and Ca(NO ３ ) ２ ・4H ２ O were weighed out to a molar ratio of 1:1, and then mixed in a mortar for 1 hour. The total amount was adjusted to 2 g. After mixing, the mixture was placed in a glove box (porcelain crucible) and fired at 500°C for 99 hours under a nitrogen atmosphere to allow the topochemical ion exchange reaction / metathesis reaction to proceed. The resulting product was then vigorously stirred in ethanol with a magnetic stirrer to remove the residual Ca(NO ３ ) ２ ・4H ２ After dissolving the O and other salts, the mixture was filtered and finally dried overnight in an oven at 80°C. The powder was collected from the container in a glove box and the target calcium composite oxide, CaMgSiO ４ The obtained calcium composite oxide CaMgSiO ４ The XRD pattern of CaMgSiO having a Kirschsteinite-type olivine framework structure calculated by simulation ４ The crystal structures of the obtained calcium composite oxide and precursor compound are shown in Table 9.

[0238]

[0239] [Example 7: Production of calcium composite oxide] In a glove box, the precursor compound obtained in the above Production Example and Ca(NO ３ ) ２ ・4H ２ O were weighed out to a molar ratio of 1:1, and then mixed in a mortar for 1 hour. The total amount was adjusted to 2 g. After mixing, the mixture was placed in a glove box (porcelain crucible) and fired at 500°C for 99 hours under a nitrogen atmosphere to allow the topochemical ion exchange reaction / metathesis reaction to proceed. The resulting product was then vigorously stirred in ethanol with a magnetic stirrer to remove the residual Ca(NO ３ ) ２ ・4H ２ After dissolving the O and other salts, the mixture was filtered and finally dried overnight in an oven at 80°C. The powder was recovered from the container in a glove box to obtain the target calcium composite oxide. The XRD patterns of the obtained calcium composite oxide are shown in Figures 43 to 46. The crystal structures of the obtained calcium composite oxide and precursor compound are shown in Table 10.

[0240]

Claims

1. A method for producing a composite oxide containing magnesium or calcium, comprising a heating step of heating a precursor compound at a temperature of 500 ° C or lower in the presence of a salt containing magnesium or calcium, and a washing step of washing with a washing liquid containing a polar solvent after the heating step, wherein the combination of the precursor compound and the composite oxide is any one of the following (A) to (E): (A) The precursor compound is represented by the general formula (1A): A １ ａ１ M １ ｍ１ D ｄ O ６ (1A) [In the formula, A １ is at least one selected from the group consisting of H, Li, Na, K, Ca, Mg, Ba, Sr, Pb, Cu, and Ag, M １ is at least one selected from the group consisting of Mg, Ca, Ti, Si, Ge, Sn, Ni, Co, Cu, Al, Cr, Mn, Fe, Ga, and Zn, D is at least one selected from the group consisting of Te, Sb, Bi, Ru, Nb, Ta, Sn, and W, and 0 < a1 ≦ 6, 0 < m1 ≦ 2, 0 < d ≦ 1.], and the composite oxide is represented by the general formula (1A'): X ａ１／２ M １ ｍ１ D ｄ O ６ (1A') [In the formula, X is Mg or Ca, provided that X is different from the above A １ . The other symbols are the same as above.]; (B) The precursor compound is represented by the general formula (1B): A ２ ａ２ M ２ ｍ２ E ２ O ７-δ (1B) [In the formula, A ２ is at least one selected from the group consisting of Li, Na, K, Rb, Cs, Ba, Sr, Pb, Cu, and Ag, M ２ is at least one selected from the group consisting of Mg, Al, Ca, Fe, Ti, V, Ni, Cu, Mn, Co, and Zn, E is at least one selected from the group consisting of V, Si, Ge, P, W, S, and B, 0 < a2 ≤ 4, 0 < m2 ≤ 2, and -2 ≤ δ ≤ 2.], and is a compound represented by The composite oxide has the general formula (1B'): X ａ２／２ M ２ ｍ２ E ２ O ７-δ (1B') [In the formula, X is Mg or Ca, provided that X is different from the above A ２ . The other symbols are the same as above.], and is a compound represented by; (C) The precursor compound has the general formula (1C): A ３ ａ３ M ３ ｍ３ GO ４ (1C) [In the formula, A ３ is at least one selected from the group consisting of Li, Na, K, Rb, Cs, Ca, Mg, Ba, Sr, Cu, and Ag, M ３ is at least one selected from the group consisting of Mg, Al, Ca, Ni, Fe, Mn, Co, Cu, and Zn, G is at least one selected from the group consisting of Si, Ge, Ti, Sn, Mn, V, and Zr, and 0 < a3 ≤ 2, 0 < m3 ≤ 1.], and is a compound represented by The composite oxide has the general formula (1C'): X ａ３／２ M ３ ｍ３ GO ４ (1C') [In the formula, X is Mg or Ca, provided that X is different from the above A ３ . The other symbols are the same as above.], and is a compound represented by; (D) The precursor compound has the general formula (1D): A ４ ａ４ M ４ ｍ４ (G'O ４ ) ｇ (1D) [In the formula, A ４ is at least one selected from the group consisting of Li, Na, K, Rb, Cs, Ba, Ca, Mg, Sr, Pb, Cu, and Ag, M ４ is at least one selected from the group consisting of Mg, Al, Ca, Ni, Cu, Zn, Fe, Mn, V, and Ti, G' is at least one selected from the group consisting of Si, Ge, P, S, W, Mo, and Zr, 0 < a4 ≤ 6, 0 < m4 ≤ 2, and 2 ≤ g ≤ 6.], and is a compound represented by the formula: The composite oxide has the general formula (1D'): X ａ４／２ M ４ ｍ４ (G'O ４ ) ｇ (1D') [wherein X is Mg or Ca, provided that X is different from the above A ４ . The other symbols are the same as those above.], and is a compound represented by the formula: (E) The precursor compound has the general formula (1E): A ５ ａ５ M ５ ｍ５ PO ４ B (1E) [wherein A ５ is at least one selected from the group consisting of Li, Na, K, Rb, Cs, Ba, Ca, Mg, Sr, Pb, Cu, and Ag, M ５ is at least one selected from the group consisting of Mg, Al, Ca, Ni, Cu, Zn, Fe, Mn, V, Co, and Ti, B is at least one selected from the group consisting of F, Cl, OH, and CO ３ , 0 < a5 ≤ 2, and 0 < m5 ≤ 2.], and is a compound represented by the formula: The composite oxide has the general formula (1E'): X ａ５／２ M ５ ｍ５ PO ４ B (1E') [wherein X is Mg or Ca, provided that X is different from the above A ５ . The other symbols are the same as those above.], and is a compound represented by the formula.

2. The production method according to claim 1, wherein the composite oxide is a compound obtained by replacing the cations constituting the precursor compound with magnesium ions or calcium ions constituting the salt.

3. The production method according to claim 1, wherein the average particle diameter of the composite oxide is 1 nm to 100 nm.

4. The production method according to claim 1, wherein the salt is a molten salt.

5. The production method according to claim 1, wherein the heating step is performed under a pressure of less than 0.2 MPa.

6. The production method according to any one of claims 1 to 5, wherein the composite oxide is an electrode material, a solid electrolyte material, an optical material, or a magnetic material.

7. XMGeO ４ 、XM ２ Si ２ O ７ 、X ２ MSi ２ O ７ 、XM ２ B ２ O ７ 、XMP ２ O ７ 、XMV ２ O ７ 、XMPO ４ F、XMTiO ４ 、XMn ２ P ２ O ７ 、XM ２ TeO ６ 、XMSiO ４ 、X １．５ M ２ SbO ６ 、X １．５ M ２ BiO ６ 、X １．５ M ２ RuO ６ 、X ２ MTeO ６ 、X ２ MSbO ６ 、X １．５ Cu ２／５ Ni ２／５ Co ２／５ Fe ２／５ Mn ２／５ SbO ６ 、X １．５ Cu １／３ Ni １／３ Co １／３ Mg １／３ Mn １／３ Cu １／３ SbO ６ 、 or X １．５ M １．５ TeO ６ [In each formula, X is Mg or Ca, and M is Fe, Mn, Mg, Ca, Co, Ni, Ni ０．５ Co ０．５ 、 Cu, or Zn.]. A composite oxide represented by 8. Na ２ Mg ２ TeO ６ A magnesium composite oxide having a ３ TeO ６ crystal structure represented by 9. Calcium composite oxide represented by CaM ２ TeO ６ having an ilmenite crystal structure.

10. Na ４ MgTeO ６ 、Na ４ CaTeO ６ 、Na ３ Mg １．５ TeO ６ 、Na ３ Zn １．５ TeO ６ 、Na ３ Co ２ RuO ６ 、Li ２ Zn ２ TeO ６ 、Na ３ Co １．５ TeO ６ 、Na ３ Cu １．５ TeO ６ 、Na ３ Mg ２ RuO ６ 、Na ３ Co ２ BiO ６ 、Na ３ NiCoBiO ６ 、Na ３ Ca ２ SbO ６ Or Na ３ NiCoSbO ６ A compound represented by

Images