JP2002121023A - Tin-based composite oxide - Google Patents

Abstract

(57) [Problem] To provide a composite oxide which is excellent in cycle characteristics and is suitably used as a negative electrode material of a high capacity non-aqueous electrolyte secondary battery. A composite oxide containing tin and a second element capable of forming a composite oxide with tin, wherein the composition of an arbitrary minute region having a cross section of 3 to 5 nmφ in the composite oxide is A composite oxide characterized by having substantially the same average composition as the entire composite oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel tin-based composite oxide, a negative electrode active material for a non-aqueous electrolyte secondary battery comprising the tin-based composite oxide, and a non-aqueous electrolysis using the negative electrode active material. The present invention relates to a liquid secondary battery.

[0002]

2. Description of the Related Art A lithium ion battery, which is a non-aqueous electrolyte secondary battery, has a positive electrode made of a positive electrode active material capable of occluding and releasing lithium ions and a current collector, and occluding and releasing lithium ions. A negative electrode composed of a negative electrode active material and a current collector capable of being formed, an electrolytic solution obtained by dissolving a lithium salt in a non-aqueous solvent, a separator, and a battery container. Due to its features, its demand has been rapidly increasing in recent years.

[0003] In the lithium ion battery, lithium ions released from the positive electrode active material during charging are occluded in the negative electrode active material, and lithium ions occluded in the negative electrode active material are discharged during discharging to form the positive electrode active material. It is occluded inside. For this reason, the charge / discharge capacity, which is one of the important characteristics of the lithium ion battery, is strongly affected by the negative electrode active material used.

[0004] In a lithium-ion battery currently in practical use, a carbon-based material such as graphite, hard carbon or soft carbon (hereinafter simply referred to as carbons) is used as a negative electrode active material. Carbon reduces the charge / discharge capacity after repeated charge / discharge compared to other negative electrode active materials such as lithium metal and lithium alloy (cycle deterioration)
Is an excellent electrode material in that it is small. However, carbon has a small specific gravity, so the charge / discharge capacity is not sufficient in volume per volume, and in order to achieve a higher charge / discharge capacity, a negative electrode active material having a higher lithium ion occlusion ability and release ability is required. Are being considered.

[0005] It is known that tin oxide has a property of absorbing and releasing lithium ions, and it has been studied for a long time to use tin oxide as an electrode active material of a lithium ion battery by utilizing the property. (DEJAN.P.ILI
C. et al. Serb. Chem. Soc. , 51 volumes, 4
89-495, 1986). And recently, Sn
The charge / discharge capacity of a lithium ion battery using tin oxide such as O or SnO ₂ as a negative electrode active material is 500 to 600 mAh.
/ G (see Japanese Patent Laid-Open No. 6-2752).
No. 68, JP-A-7-122274, etc.). Since tin oxide has a specific gravity about 2 to 4 times higher than that of carbon, tin oxide has begun to attract attention as a negative electrode active material for providing a lithium ion battery having a high charge / discharge capacity per volume.

However, when SnO or SnO ₂ is used as the negative electrode active material, the difference (irreversible capacity) between the charge capacity and the discharge capacity at the time of the initial charge / discharge is large, and the charge / discharge capacity at the initial stage is high, but the charge / discharge capacity is high. It was found that the charge / discharge capacity decreased as the process was repeated, and this stability (cycle characteristics)
Various composite oxides obtained by adding a second element to tin oxide have been studied for the purpose of improving the electric charge and further increasing the charge / discharge capacity.

For example, as a method for producing a composite tin oxide powder containing a second element such as tin and silicon, a mixture of a silicon oxide powder and a tin oxide powder is used as a raw material powder, and the raw material powder is melted at a high temperature to form a glass. (Melting method) in which the vitrified mass is pulverized by pulverization after cooling, and the composite tin oxide powder obtained by the melting method is used as a negative electrode active material for a lithium secondary battery. It is said that when used as a substance, the charge / discharge capacity is high and the cycle characteristics are improved (Japanese Patent Application Laid-Open No. 7-288123).

Further, a raw material solution in which a tin compound and a compound containing a second element capable of forming a complex oxide with tin are dissolved in an organic solvent and a basic aqueous solution are simultaneously added to alcohol to precipitate a solid, The composite tin oxide synthesized by the sol-gel method of heat-treating the obtained solid has a large number of fine pores and the like in the particles, and the composite oxide remains mechanical even after repeated occlusion and release of lithium ions. It is known that the composite tin oxide is less likely to break down and exhibits better cycle characteristics than the composite tin oxide obtained by the melting method (Japanese Patent Application Laid-Open No. H11-292535).

[0009]

However, with any of the above composite oxides, the cycle characteristics when used as a negative electrode active material of a lithium battery were not sufficient as compared with the case where carbons were used.

As described above, a negative electrode active material that increases the charge / discharge capacity of a lithium secondary battery and provides the same level of cycle characteristics as a conventional lithium secondary battery is not known.
It is desired to provide such a substance.

[0011]

Means for Solving the Problems In order to solve the above-mentioned problems by improving the composite tin oxide, the present inventors have synthesized a composite tin oxide by a sol-gel method under various synthesis conditions and evaluated the characteristics thereof. Was. As a result, as disclosed in
In the method for producing a tin-based composite oxide disclosed in Japanese Patent Application Publication No. 535/535, when tin halide is used as a tin compound soluble in an organic solvent, and when the amount of a basic compound to be used is in a specific range, lithium tin is used. It has been found that a composite tin oxide having good charge / discharge cycle characteristics can be obtained when used as a secondary battery negative electrode. Various studies were conducted on the composite tin oxide. As a result, the composite tin oxide was entirely homogenous at the nano level as compared with the conventional composite tin oxide, and a novel composite having a microstructure greatly different from that of the conventional composite tin oxide. It was found that the oxide was tin oxide, and the present invention was completed.

That is, the present invention relates to a tin-based composite oxide containing tin and at least one second element capable of forming a composite oxide with tin, wherein the tin-based composite oxide has a thickness of 9 to 25 nm.
^2. A tin-based composite oxide, characterized in that the composition of any minute region having a cross-sectional area of ² is substantially the same as the average composition of the entire composite oxide.

The microstructure of the composite oxide of the present invention is as follows:
In the case where energy dispersive X-ray spectroscopy using a transmission electron microscope is performed on the composite oxide, the intensity ratio of characteristic X-rays of tin and the second element measured under the condition of an analysis region diameter of 3 to 5 nmφ And the above-mentioned intensity ratio when measured under the condition of 50 nmφ (for example, when the intensity ratio of the former is A and the intensity ratio of the latter is B, A / B is 0.6 to
1.7).

Accordingly, the composite oxide according to the present invention comprises tin,
And a tin-based composite oxide containing at least one kind of second element capable of forming a composite oxide with tin, wherein an analysis region diameter of 3 to 5 nmφ and 50 n
The intensity ratio of characteristic X-rays of tin and the second element in each analysis region measured when performing energy dispersive X-ray spectroscopy using a transmission electron microscope under the condition of mφ is A
And B, it can be said that the tin-based composite oxide is characterized in that A / B is 0.6 to 1.7.

Further, the present invention provides a raw material obtained by dissolving a tin halide and at least one organic solvent-soluble compound containing at least one second element capable of forming a composite oxide with tin in an organic solvent. A solution and an aqueous solution of a basic compound are simultaneously added to alcohol and reacted to precipitate a solid, and the deposited solid is heat-treated to produce a tin-based composite oxide. The method for producing a tin-based composite oxide according to the present invention, wherein the number of moles of the basic compound contained is set to 1.3 to 1.6 times the number of moles of all halogen atoms contained in the raw material solution. is there.

According to the production method, the tin-based composite oxide of the present invention can be easily produced. In the above production method, the basic compound added to the alcohol together with the raw material solution acts as a catalyst for the hydrolysis and polymerization of the tin halide and the second element compound. It is thought that the tin-based composite oxide of the present invention can be produced because unique conditions are created such that the reaction proceeds uniformly.

A third aspect of the present invention is a negative electrode active material for a non-aqueous electrolyte secondary battery comprising the above-described composite oxide of the present invention, and a fourth aspect of the present invention is a negative electrode active material of the present invention. A non-aqueous electrolyte secondary battery characterized in that it is used.

The non-aqueous electrolyte secondary battery of the present invention is characterized by high charge / discharge capacity and good cycle characteristics.

Although the present invention is not limited by the theory, it is considered that the cycle characteristics are improved by the following mechanism in the present invention. That is, generally, in a lithium battery using a tin-based composite oxide as a negative electrode active material, a tin component in the composite oxide binds or dissociates with lithium ions during charge / discharge, and inserts and releases lithium ions. Since the occupied volume is different between the (bonded) state and the released (dissociated) state, expansion and contraction occur during charge and discharge. However, when a conventional tin-based composite oxide is used as the negative electrode active material, the composite oxide It is considered that since a large tin component is segregated in the material, a large stress concentration occurs due to the expansion and contraction, resulting in mechanical destruction and a reduction in capacity.
On the other hand, in the composite oxide of the present invention, since the tin component is uniformly finely dispersed, such concentration of stress does not occur, and it is considered that the cycle characteristics are hardly deteriorated.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The composite oxide of the present invention comprises tin and a composite oxide of at least one second element capable of forming a composite oxide with tin.

The second element is not particularly limited as long as it can form a composite oxide with tin. Alkaline earth metal elements such as Ca, Sr, and Ba; La, Ce, Pr, Nd, S
m, Eu, Gd, Tb, Dy, Ho, Er, Tm, Y
rare earth elements such as b and Lu; Sc, Ti, V, Cr, M
n, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb,
Mo, Ru, Cd, Hf, Ta, W, Re, Os, I
transition elements such as r, Pt, Au, Hg; B, Al, Ga,
Group 13 elements of the periodic table such as In and Tl; Ge, Si, Pb
Group 14 elements of the periodic table excluding carbon and tin; P, As,
It can be selected from elements of Group 15 of the periodic table such as Sb and Bi.

The second element may be one of the above elements or a combination of any two or more of them. If a suitable combination of tin and the second element is exemplified, Sn-
Si, Sn-Si-Al, Sn-Si-Zr, Sn-S
i-B, Sn-Si-P, Sn-Si-Ti, Sn-S
i-Al-B, Sn-Si-Zr-B, Sn-Si-B
-P, Sn-Al, Sn-Al-B, Sn-Al-P,
Sn-Al-Zr, Sn-Al-BP, Sn-Zr,
Sn-Zr-B, Sn-Zr-P, Sn-Zr-B-
P, Sn-BP, Sn-Ti, Sn-Ti-Al, S
n-Ti-B, Sn-Ti-P, Sn-Ti-BP,
Sn-Ti-Zr and the like.

Among the above preferred combinations, when tin and silicon or a combination of silicon and other second elements are used, they are used as a negative electrode active material for a non-aqueous electrolyte secondary battery such as a lithium ion battery. Occlusion of lithium ions
It is preferable because the amount of release is large and the cycle characteristics are particularly excellent.

Although the ratio of tin to the total amount of tin and the second element in the composite oxide of the present invention is not particularly limited, the amount of occlusion and release of lithium ions is large, the change with time is small, and the nonaqueous electrolyte 30 to 70 atomic%, especially 4%, because it is particularly suitable for use as an active material for a negative electrode for a secondary battery.
It is preferably 0 to 60 atomic%.

Since the composite oxide of the present invention is a composite oxide of tin and the second element as described above, it contains an oxygen atom in addition to tin and the second element. Since the oxygen atom is present in combination with tin and the second element, the content is almost uniquely determined by the content and the valence of the tin atom and the type, content and the valence of the second element. Is done. However, tin and part of the second element may have dangling bonds (so-called dangling bonds), and about 10 atomic% of oxygen atoms are halogen atoms such as fluorine, chlorine, bromine and iodine or sulfur, It may be substituted with a chalcogen atom such as selenium and tellurium. The valences of tin and the second element in the tin-based composite oxide of the present invention are not particularly limited.

The composite oxide of the present invention is contained in the composite oxide.
Spatial mixing state of the existing tin and the second element, in other words
The microstructure is different from the conventional tin-based composite oxide. That is,
The bright composite oxide is homogeneous at the nanometer level,
9 to 25 nm in the compound ^TwoAny with a cross-sectional area of
The composition of the minute region is substantially equal to the average composition of the entire composite oxide.
Characteristically identical. Note that any of the above
The thickness of the minute area is generally determined in relation to the analysis method described later.
It is always 200 nm or less.

The fine structure as described above can be easily confirmed by observing the composite oxide with a transmission electron microscope (TEM). That is, it can be confirmed by the fact that the density of the contrast due to the composition distribution is hardly observed in the bright field image of the composite oxide observed at 2.8 million times by TEM. In a bright-field image of a known composite oxide, contrast shading due to composition distribution is observed, and the tin component in the complex oxide is segregated, whereas in the complex oxide of the present invention, such contrast shading is observed. Is not observed.

The present inventors have studied to quantitatively express the homogeneity as described above, and found that the composite oxide was subjected to energy dispersive X-ray spectroscopy (hereinafter simply referred to as EDS) using a transmission electron microscope (TEM). ), The intensity ratio of characteristic X-rays between tin and the second element measured under the condition of an analysis region diameter of 3 to 5 nmφ is A, and 50 n
When the intensity ratio of characteristic X-rays of tin and the second element measured under the condition of mφ is B, and A / B is in the range of 0.6 to 1.7, It shows a unique fine structure in which contrast is not observed, and has excellent characteristics when used as a negative electrode active material for a non-aqueous electrolyte secondary battery (that is, a characteristic having a large charge / discharge capacity and good cycle characteristics). Was found. Therefore,
It can be said that the composite oxide of the present invention is a tin-based composite oxide in which the A / B is 0.6 to 1.7.

The above methods A and B can be obtained by EDS using an electron beam of a TEM as an excitation source as follows. That is, first, the beam diameter (analysis area diameter) of the electron beam irradiating the composite oxide is set to 50 nmφ, and EDS is performed.
The characteristic X-ray intensity of tin and the characteristic X-ray intensity of the second element are measured, and the ratio thereof {(characteristic X-ray intensity of tin in the analysis region of 50 nmφ) / (characteristic X-ray intensity of the analysis region of 50 nmφ second element)} Is B. Next, the beam diameter of the electron beam to be irradiated, that is, the diameter of the analysis area is set to 3 at an arbitrary point in the analysis area.
The characteristic X-ray intensity of tin and the characteristic X-ray intensity of the second element in the minute region were measured by EDS with a thickness of ５5 nmφ, and the ratio {((characteristic X-ray intensity of tin in analysis region 3 to 5 nmφ) / (analysis region 3 to The characteristic X-ray intensity of the second element having a diameter of 5 nmφ)} may be A.

In the TEM used for the EDS, the type of the electron gun is not particularly limited as long as a beam diameter of 3 to 5 nmφ can be obtained. However, when a field emission type TEM is used, an electron beam having a beam diameter of 3 to 5 nmφ is used. Can be obtained. The electron beam applied to the measurement sample is scattered and diffused inside the sample, and characteristic X-rays emitted from a wider range than the beam size of the irradiated electron beam are detected by the EDS. Although the actual analysis area diameter may be slightly different, the degree of diffusion of the electron beam inside the sample becomes smaller as the accelerating voltage of the irradiated electron beam becomes higher and as the sample thickness becomes smaller. In order to make the beam diameter of the electron beam substantially equal to the analysis area diameter, it is preferable that the beam diameter of the electron beam irradiating the measurement sample is about 200 kV or more and the sample thickness is 200 nm or less.

When there are a plurality of second elements, A and B are determined for the same kind of second element. Since the composition of the composite oxide of the present invention is uniform, the A / B is 0.6 to 1.0 regardless of the type of the second element.
7 range. Further, in the composite oxide of the present invention, for example, when A / B was obtained for 10 different visual fields, the values were all 0.6 to 1.7. You can see that it is kept.

Although the method for producing the composite oxide of the present invention is not particularly limited, it can be suitably produced by the following method of the present invention.

That is, a raw material solution obtained by dissolving a tin halide and at least one organic solvent-soluble compound containing at least one second element capable of forming a composite oxide with tin in an organic solvent; The aqueous solution is added to an alcohol at the same time to react to precipitate a solid, and the deposited solid is heat-treated to produce a tin-based composite oxide, wherein the molar ratio of the basic compound contained in the aqueous solution of the basic compound is When the number is set to 1.3 to 1.6 times the number of moles of all the halogen atoms contained in the raw material solution, it is possible to suitably manufacture. Note that the halogen atom may be an ion.

The tin halide used in the raw material solution in the production method of the present invention is a salt of a halogen such as Cl, Br, I, or F with tin or a hydrate thereof.
l ₂ , SnCl ₂ .2H ₂ 0, SnCl ₄ , SnCl ₄ .5
_{H 2 O, SnBr 2, SnBr} 4, SnI 2, SnF 2 , and the like. Further, among the tin halides, chlorides and bromides are particularly preferable. Specifically, SnCl ₂ , SnC
_{l 2 · 2H 2 0, SnCl} 4, SnCl 4 · 5H 2 O, Sn
Examples thereof include Br ₂ and SnBr ₄ . Further, the tin halide modified with an organic compound, for example, Sn (CH
₃ ) ₂ Cl ₂ etc. can also be used. The tin halide may be a mixture of two or more kinds.

It should be noted that, as the ratio of tetravalent tin in the tin atoms contained in the raw material solution increases, the dispersion state of the tin component in the obtained composite oxide tends to be improved. However, as the proportion of tetravalent tin increases, the irreversible capacity in the first cycle when used as a lithium ion battery negative electrode increases. Accordingly, the valence of tin atoms in the raw material solution is not particularly limited, but it is preferable that divalent tin is 60 to 90 mol% in terms of tin and tetravalent tin is 10 to 40 mol%.

In order to keep the ratio of divalent and tetravalent tin in the raw material solution within the above range, a divalent tin compound as a tin halide to be dissolved is 60 to 90 mol% in terms of tin and a tetravalent halogen. What contains tin oxide in an amount of 10 to 40 mol% in terms of tin may be used. Further, an oxidizing substance such as oxygen is introduced into a solution in which a predetermined amount of divalent tin halide is dissolved, and the whole is oxidized to form tetravalent tin. The method of dissolving or dissolving the divalent tin halide, and then performing the same oxidation as described above to partially oxidize the divalent tin, the divalent tin and the tetravalent tin fall within the above range. You may do so. At this time, in the latter method, it is preferable that the amount of tetravalent tin generated by oxidation is preliminarily determined by conducting a preliminary oxidation experiment to determine the reaction conditions for obtaining the desired amount of tin.

[0037] In addition, an alloy containing at least one second element may be used.
Solvent-soluble compound (also referred to as a second element raw material compound)
Contains a second element soluble in organic solvents with tin halide
Any compound can be used without any limitation. In general,
Halides of two elements, alkoxide compounds, nitrates,
Sulfates show some solubility in organic solvents
Many of these compounds are used in selecting compounds.
From those with high solubility depending on the type of solvent
And use it. A suitably usable second element raw material compound
To give a concrete example, the second element raw material compound
When the compound is an alkaline earth metal, the alkaline earth metal
Halides and hydrates, nitrates and water thereof
Without special restrictions
Can be used. As a specific compound, CaCl
_Two, CaBr_Two, CaI_Two, CaCl_Two・ 6H_TwoO, CaB
r_Two・ 6H_TwoO, CaI_Two・ 6H_TwoO, Ca (NO_Three)_Two・ 4
H _TwoO, Ca (NO_Three)_Two・ XH_TwoO, Ca (OCH_Three)_Two,
Ca (OC_TwoH_Five)_Two, Ca (OC_ThreeH₇)_Two, Ca (OC_Four
H₉)_Two, SrCl_Two, SrBr_Two, SrI_Two, SrCl_Two・
6H_TwoO, SrBr_Two・ 6H_TwoO, SrI_Two・ 6H_TwoO, S
r (NO_Three)_Two, Sr (OCH_Three)_Two, Sr (OC
_TwoH_Five)_Two, Sr (OC_ThreeH₇)_Two, Sr (OC_FourH₉)_Two, B
aCl_Two, BaBr_Two, BaI_Two, BaCl_Two・ 2H_TwoO,
BaBr_Two・ 2H_TwoO, BaI_Two・ 2H_TwoO, Ba (N
O_Three)_Two, Ba (OCH_Three)_Two, Ba (OC_TwoH_Five)_Two, Ba
(OC_ThreeH₇)_Two, Ba (OC_FourH₉)_Two, Etc.
Can be.

The second element raw material compound is a compound of a rare earth element
In the case of is a rare earth element halide and its
Hydrates, nitrates and their hydrates, alkoxides, etc.
And can be used without any particular limitation. Concrete
LaCl as a typical compound _Three, LaBr_Three, LaI_Three,
LaCl_Three・ 7H_TwoO, La (NO_Three)_Three・ 6H_TwoO, La
(OCH_Three)_Three, La (OC_TwoH_Five)_Three, La (OC
_ThreeH₇)_Three, CeCl_Three, CeBr_Three, CeI_Three, CeCl_Three
・ 6H_TwoO, Ce (NO_Three)_Three・ 6H_TwoO, PrCl_Three, P
rCl_Three・ 7H_TwoO, Pr (NO_Three)_Three・ 6H_TwoO, Pr
(OC_ThreeH₇)_Three, NdCl_Three, NdBr_Three, NdCl_Three・ 6
H_TwoO, Nd (NO_Three)_Three・ 5H_TwoO, SmCl_Three・ XH
_TwoO, Sm (NO_Three)_Three・ XH_TwoO, Sm (OC_ThreeH₇)_Three,
EuCl_Three・ 6H_TwoO, Eu (NO_Three)_Three・ 6H_TwoO, Gd
Cl_Three, GdCl_Three・ 6H_TwoO, Gd (NO_Three)_Three・ 5H
_TwoO, TbCl_Three, TbCl_Three・ XH_TwoO, Tb (NO_Three)_Three
・ XH_TwoO, DyCl_Three, DyCl_Three・ XH_TwoO, Dy (N
O_Three)_Three・ 5H_TwoO, Dy (OC_ThreeH₇)_Three, HoCl _Three, H
oCl_Three・ 6H_TwoO, Ho (NO_Three)_Three・ 5H_TwoO, ErC
l_Three・ 6H_TwoO, Er (NO_Three)_Three・ 5H_TwoO, Er (OC_Three
H₇)_Three, TmCl_Three・ 6H_TwoO, Tm (NO_Three)_Three・ 5H_Two
O, YbBr_Three, YbI_Three, YbCl_Three・ 6H_TwoO, Yb
(NO_Three)_Three・ XH_TwoO, LuCl_Three, Lu (NO_Three)_Three・ X
H_TwoO and the like can be exemplified.

The second element raw material compound is a transition element compound
In some cases, halides of transition elements and their hydration
Substances, oxyhalides, acetates, nitrates and their water
Hydrate, sulfate and its hydrate, ammonium salt, transition
Without any particular restrictions, such as elemental alkoxides
Can be used. As a specific compound, ScCl
_Three, ScCl_Three・ XH_TwoO, Sc (NO_Three)_Three・ XH_TwoO, T
iCl_Four, TiBr_Four, Ti (OCH_Three)_Two, Ti (OC_Two
H_Five)_Two, Ti (OC_ThreeH₇)_Two, Ti (OC_FourH₉) _Two, VB
r_Three, VCl_Two, VCl_Three, VCl_Four, VOBr_Two, VOB
r_Three, VOCl_Three, VF_Three, VF_Four, VF_Five, VI_Three・ 6H_Two
O, VO (OCH_Three)_Three, VO (OC_TwoH_Five)_Three, VO (O
C_ThreeH₇)_Three, VO (OC_FourH₉)_Three, CrCl_Three, CrB
r_Three, CrCl_Three・ XH_TwoO, CrBr_Three・ 6H_TwoO, Cr
I_Three・ XH_TwoO, Cr (CH_ThreeCOO)_Three・ XH_TwoO, Mn
Cl_Two, MnBr_Two, MnI_Two, MnCl_Two・ 4H_TwoO, M
nBr_Two・ 4H_TwoO, MnI_Two・ 4H_TwoO, Mn (NO_Three)_Two
・ 6H_TwoO, Mn (OC_ThreeH₇)_Two, Mn (OC_TwoH_Five)_Two,
FeBr_Two, Fe_TwoBr ・ 6H_TwoO, FeBr_Three, FeBr
_Three・ 6H_TwoO, Fe (OH) (CH3COO)_Two, FeC
l_Two, FeCl_Three・ 6H_TwoO, FeCl_Three, FeI_Two, Fe
(NO_Three)_Three・ 9H_TwoO, (NH_Four)_TwoFe (SO_Four)_Two・ X
H_TwoO, (NH_Four) Fe (SO_Four)_Two・ XH_TwoO, Fe (O
CH_Three)_Three, Fe (OC_TwoH_Five)_Three, Fe (OC_ThreeH₇)_Three, F
e (OC_FourH₉)_Three, CoBr_Two, CoBr_Two・ 6H _TwoO, C
o (C_TwoH_ThreeO_Two)_Two・ 4H_TwoO, CoCl_Two, CoCl_Two・
6H_TwoO, CoI_Two, Co (NO_Three)_Two・ 6H_TwoO, Co
(OC_ThreeH₇)_Two, NiBr_Two, NiBr_Two・ XH _TwoO, Ni
(CH_ThreeCOO)_Two・ XH_TwoO, NiCl_Two, NiCl_Two・
6H_TwoO, NiI_Two, NiI_Two・ 6H_TwoO, Ni (NO_Three)_Two
・ 6H_TwoO, CuBr, CuBr_Two, Cu (CH_ThreeCO
O)_Two, CuCl, CuCl_Two, CuCl_Two・ 2H_TwoO, C
u (NO_Three)_Two・ 3H_TwoO, ZnBr_Two, Zn (CH_ThreeCO
O)_Two・ 2H_TwoO, ZnCl_Two, ZnI_Two, Zn (NO_Three)_Two
・ 6H_TwoO, Zn (OCH_Three)_Two, Zn (OC_TwoH_Five)_Two, Z
n (OC_ThreeH₇)_Two, Zn (OC_FourH₉)_Two, YBr_Three, YC
l_Three・ 6H_TwoO, YCl_Three, Y (NO_Three)_Three・ 6H_TwoO, Y
(OCH_Three)_Three, Y (OC_TwoH_Five)_Three, Y (OC_ThreeH₇)_Three, Z
rBr_Four, ZrCl_Four, ZrI_Four, ZrO (CH_ThreeCOO)
_Two, ZrOCl_Two・ 8H _TwoO, ZrI_Two・ XH_TwoO, ZrO
(NO_Three)_Two・ 2H_TwoO, Zr (SO_Four)_Two・ 4H_TwoO, Zr
(OCH_Three)_Four, Zr (OC_TwoH_Five)_Four, Zr (OC
_ThreeH₇)_Four, Zr (OC_FourH₉)_Four, NbCl_Five, NbOC
l_Three, NbBr_Five, NbF_Five, Nb (OCH_Three)_Five, Nb
(OC_TwoH_Five)_Five, Nb (OC_ThreeH₇)_Five, Nb (OC_FourH₉)
_Five, MoBr_Two, MoBr_Three, MoCl_Five, (NH_Four)₆Mo
₇O_{twenty four}・ 4H_TwoO, Mo (OC_TwoH_Five)_Five, RuCl_Three・ H_Two
O, PdCl_Two・ 2H_TwoO, AgNO_Three, CdBr_Two・ 4H
_TwoO, CdBr_Two, CdCl_Two・ 5 / 2H_TwoO, CdC
l_Two, CdF_Two, CdI_Two, Cd (NO_Three)_Two・ 4H_TwoO, H
fCl_Four, HfOCl_Two・ 8H_TwoO, Hf (OCH_Three)_Four,
Hf (OC_TwoH_Five)_Four, Hf (OC_ThreeH₇)_Four, Hf (OC_Four
H₉)_Four, TaCl_Five, TaBr_Five, Ta (OCH_Three)_Five, T
a (OC_TwoH_Five)_Five, Ta (OC_ThreeH₇)_Five, Ta (OC
_FourH₉)_Five, WCl_Five, WCl₆, WBr₆, W (OC_TwoH_Five)
_Five, W (OC_ThreeH₇)_Five, ReCl_Three, ReCl_Five, OsCl
_Three, IrCl_Three・ 3H_TwoO, IrCl_Three, IrCl_Four, Pt
Cl _Four・ 5H_TwoO, H_TwoPtCl₆・ NH_TwoO, AuBr_Three・
xH_TwoO, AuCl_Three・ XH_TwoO, AuHCl_Four・ 4H
_TwoO, Hg_TwoBr_Two, HgCl_Two, Hg (NO_Three)_Two・ 2H_Two
O, HgSO_FourAnd the like.

When the starting compound of the second element is a compound of an element of Group 13 of the periodic table, a halide of the element of Group 13 of the periodic table and its hydrate, ammonium salt, sulfate, organic acid salt, alkoxide, etc. Thus, it can be used without any particular limitation. As a specific compound, B
₂ O ₃ , (NH ₄ ) ₂ O.5B ₂ O ₃ .8H ₂ O, BCl ₃ , B
Br ₃ , BI ₃ , H ₃ BO ₃ , B (OCH ₃ ) ₃ , B (OC _{2
H 5) 3, B (OC} 3 H 7) 3, B (OC 4 H 9) 3, AlBr
_{3, AlCl 3 · 6H 2 O} , AlCl 3, AlI 3, Al
_{(NO 3) 3 · 9H 2} O, Al 2 (SO 4) 3, Al 2 (S
O ₄ ) ₃ .nH ₂ O, Al (OCH ₃ ) ₃ , Al (OC
_{2 H 5) 3, Al (} OC 3 H 7) 3, Al (OC 4 H 9) 3, G
aBr ₃ , GaCl ₃ , GaI ₃ , Ga (NO ₃ ) ₃ .xH ₂
O, Ga ₂ (SO ₄ ) ₃ , Ga ₂ (SO ₄ ) ₃ .xH ₂ O, G
a (OCH ₃ ) ₃ , Ga (OC ₂ H ₅ ) ₃ , Ga (OC
_{3 H 7) 3, Ga (} OC 4 H 9) 3, InBr 3, InCl 3,
InCl ₃ .xH ₂ O, InI ₃ , In (NO ₃ ) ₃ .xH ₂
O, In ₂ (SO ₄ ) ₃ , In ₂ (SO ₄ ) ₃ .xH ₂ O, I
n (OCH ₃ ) ₃ , In (OC ₂ H ₅ ) ₃ , In (OC
_{3 H 7) 3, In (} OC 4 H 9) 3, CH 2 (COOTl) 2,
TlOOCH and the like can be exemplified.

When the starting compound of the second element is a compound of an element of Group 14 of the periodic table, a halide of the element of Group 14 of the periodic table and its hydrate, ammonium salt, sulfate, organic acid salt, alkoxide, etc. Thus, it can be used without any particular limitation. As a specific compound, GeB
r ₄ , GeCl ₄ , GeI ₄ , Ge (OCH ₃ ) ₄ , Ge
(OC ₂ H ₅ ) ₄ , Ge (OC ₃ H ₇ ) ₄ , Ge (OC ₄ H ₉ )
_{4 and the} like. When a silicon compound is added as the second element raw material compound, the compound represented by the general formula S
_{i (OR A) 4, R} B Si (OR A) 3, R B R C Si (O
_A silicon alkoxide represented by R _A ) ₂ is used. Here, R _A , R _B , and R _C are each a linear or branched alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group; an ethenyl group, a propenyl group, a butenyl group, and a pentenyl group. And a straight-chain or branched alkenyl group such as a group, and an aryl group such as a phenyl group. Specific examples of silicon alkoxide include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, phenyltrimethoxysilane, propyltrimethoxysilane, n-butyltrimethoxy Silane, isobutyltrimethoxysilane, n-hexyltrimethoxysilane, n-octadecyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, amyltriethoxysilane, phenyltriethoxysilane, n-octyltriethoxysilane, n- Octadecyltriethoxysilane, n-dodecyltriethoxysilane, methyltributoxysilane, ethyltributoxysilane, ethyltripropoxysilane, vinyltriethoxy Silane, allyl triethoxy silane, diphenyl dimethoxy silane, dimethyl diethoxy silane, vinyl methyl diethoxy silane, diethyl dimethoxy silane, ethyl methyl diethoxy silane.
As the silicon halide, SiCl ₄ , SiHCl ₃ , S
iH ₂ Cl _{2 and the} like.

The second raw material compound is an element belonging to Group 15 of the periodic table.
In the case of a compound of the formula
And its hydrates, ammonium salts, sulfates,
There are no particular restrictions on acid salts and alkoxides.
Can be used. As a specific compound, P
_TwoO_Five, PBr_Three, PCl_Three, POBr_Three, POCl_Three, PO
(OCH_Three)_Three, PO (OC_TwoH_Five)_Three, PO (OC
_ThreeH₇)_Three, PO (OC_FourH₉)_Three, P (OCH_Three)_Three, P (O
C_TwoH_Five)_Three, AsBr_Three, AsCl_Three, AsI_Three, As (O
CH_Three)_Three, As (OC_TwoH_Five)_Three, As (OC_ThreeH7)_Three,
SbBr_Three, SbCl_Three, SbCl_Five, SbOCl, Sb_Two
(SO_Four)_Three, Sb (OCH_Three)_Three, Sb (OC_TwoH_Five) _Three,
Sb (OC_ThreeH₇)_Three, Sb (OC_FourH₉)_Three, BiBr_Three,
BiCl_Three, BiI_Three, Bi (NO_Three)_Three・ XH_TwoO, Bi
OCI, Bi (OC_ThreeH₇)_ThreeEtc. can be exemplified
You.

When the second element raw material compound is a chalcogen element compound, a chalcogen element halide and its hydrate, ammonium salt, sulfate, organic acid salt,
An alkoxide can be used without any particular limitation. Specific compounds include S ₂ Cl ₂ and SC
l ₂ , SeBr ₄ , SeCl ₄ , SeI ₄ , TeBr ₄ , T
eCl ₄ and TeO ₄ H ₂ .xH ₂ O can be exemplified.

As the solvent used for the raw material solution, an organic solvent that dissolves the tin halide and the second element raw material compound can be used without any limitation, but there are many types of soluble tin halide and the second element raw material compound. , And alcohol, acetone, acetylacetone,
It is preferable to use acetonitrile or the like. Among these organic solvents, alcohols are particularly preferred.

Specific examples of preferably usable alcohols include methanol, ethanol, propanol, butanol, octanol, 2-methoxyethanol, and 2-methoxyethanol.
-Ethoxyethanol, ethylene glycol, 1-methoxy-2-propyl alcohol, methoxyethoxyethanol, 2-phenylethyl alcohol, benzyl alcohol, allyl alcohol, 2-methyl-2-propen-1-ol, 3-methyl-3- Buten-1-ol and the like can be mentioned. Among them, methanol and ethanol are preferable because of high solubility of tin halide, and methanol is more preferable because it is inexpensive and easily available. The above alcohol is usually used alone, but a mixture of two or more alcohols can be used to control the reactivity and solubility with the tin halide or the second element raw material compound.

The method for dissolving the tin halide and the second element raw material compound in the organic solvent is not particularly limited. For example, a method in which an organic solvent is dropped into a mixture of a tin halide and a second element raw material compound under stirring, or a method in which a tin halide and a second element raw material compound are simultaneously or sequentially dissolved in an organic solvent under stirring Can be used. After that, a compound having a bond via an oxygen atom between the tin atom and the second element, etc. is generated by a sufficient reaction such as refluxing, and as a result, the oxygen atom is finally formed in the composite oxide finally obtained. The probability that the element that binds to tin via the second element is the second element is increased, and the cycle characteristics of lithium ion occlusion / release are further improved.

In addition, acetylacetone, ethyl acetoacetate, diethyl malonate, or formic acid, acetic acid, oxalic acid, tartaric acid, lactic acid, succinic acid, etc. are used for controlling the solubility, hydrolysis rate, polycondensation reaction rate and the like of the raw material solution. Acid, citric acid, butyric acid, propionic acid, fumaric acid, maleic acid,
Organic acids such as phthalic acid, polyethylene glycol, cellulose, surfactants and the like may be added as optional components.

The concentration and storage state of the raw material solution used in the production method of the present invention are not particularly limited as long as they satisfy the above-mentioned conditions. However, in order to prevent the tin compound and the compound containing the second element which have been dissolved once from being precipitated and changing the composition, the concentration is the total molar concentration of the dissolved tin halide and all of the second element raw material compounds. It is preferable that the content is 0.1 to 20 mol%. After adjusting the valence of tin to avoid a change in the valence of dissolved tin, the raw material solution is stored in an atmosphere of a non-oxidizing gas such as argon or nitrogen until reacted. It is preferable to keep it.

According to the production method of the present invention, from the viewpoint that the tin-based composite oxide of the present invention exhibiting excellent characteristics as a negative electrode active material for a non-aqueous electrolyte secondary battery can be obtained, Of a tin halide having a molar ratio of divalent: tetravalent = 6: 4 to 9: 1 of tin halide and tetravalent tin halide, and a second element raw material compound dissolved in an organic solvent. A raw material solution comprising a solution in which the ratio of tin to the total amount of tin and the second element is 30 to 70 atomic%, or a mixture of divalent tin halide and tetravalent tin halide in 2
Valence: tetravalent = 9: 1 to 10: 0 molar ratio of tin halide, silicon, germanium, zirconium, titanium,
A solution in which a second element raw material compound containing at least one second element selected from hafnium, aluminum, phosphorus, boron, and lead is dissolved in an organic solvent, wherein tin is based on the total amount of tin and the second element. It is preferable to use a raw material solution composed of a solution having a ratio of 30 to 70 atomic%.

In the production method of the present invention, the raw material solution and the aqueous solution of the basic compound (hereinafter, also referred to as a basic aqueous solution) are simultaneously added to alcohol and reacted to form particles. When the raw material solution and the basic aqueous solution are not added at the same time, the reaction conditions are not constant, and the segregation tends to occur, which is not preferable. Further, the raw material solution and the basic aqueous solution need to be independently added without being mixed in advance. If the two liquids are mixed in advance, the reaction occurs before the addition to the alcohol, the reaction conditions become non-uniform, and segregation tends to occur, which is not preferable.

At this time, the basic aqueous solution added at the same time as the above-mentioned raw material solution is not particularly limited as long as its pH exceeds 7, and may be an alkaline aqueous solution such as aqueous ammonia, sodium hydroxide, potassium hydroxide or lithium hydroxide. A known basic aqueous solution such as an aqueous solution of a metal or alkaline earth metal hydroxide or an aqueous solution of a quaternary ammonium hydroxide such as tetramethylammonium hydroxide can be used without any limitation. However, the pH of the basic aqueous solution is from 10 to 13 from the viewpoint that the particle formation reaction can be uniformly performed while avoiding the occurrence of a locally high pH portion at the time of addition.
5, more preferably 11.0 to 1
3.5. The basic aqueous solution has a pH of 11 to prevent the composition of the composite oxide obtained by incorporation of metal ions in the basic aqueous solution into the composite oxide from the composition of the raw material solution. 0.5 to 13.5
It is particularly preferable to use ammonia water. In addition, a water-soluble alcohol can be added to these basic aqueous solutions in order to reduce a sudden or local reaction.

In the production method of the present invention, in order to obtain the composite oxide of the present invention in which tin and the second element are uniformly dispersed,
It is important to control the rate of hydrolysis and polymerization of the tin halide and the second element raw material compound as the raw materials.
The basic compound in the basic aqueous solution serves as a neutralizer for the tin halide in the raw material solution and also serves as a neutralizer or hydrolysis catalyst for the raw material compound of the second element. By adjusting the relative amount of the basic compound to the atom, it is possible to adjust the hydrolysis or polymerization rate of the tin halide and the second element raw material compound. In order to obtain the composite oxide of the present invention, the number of moles of the basic compound contained in the aqueous solution of the basic compound is 1.3 to 1.6 times the number of moles of all halogen atoms contained in the raw material solution, particularly, It is important that the ratio be 1.45 to 1.55 times.

The alcohol to which the raw material solution and the basic aqueous solution are added is not particularly limited, but is preferably a water-soluble alcohol. Examples of alcohols that can be suitably used include methanol, ethanol, and isopropyl alcohol. And the like.

The alcohol functions as a medium for the reaction that takes place after the addition of the raw material solution and the basic aqueous solution. Since the alcohol has a high affinity for both the solutions to be added, the reaction proceeds. Homogeneous particles that occur homogeneously and form the composite oxide are formed. In the production method of the present invention, it is essential to use an alcohol as the reaction medium. However, a solvent having the same action may be used. For example, an embodiment in which a mixed solution of an alcohol and a basic aqueous solution is used as a reaction medium is preferable because the present composite oxide powder including particles having good homogeneity is obtained. The basic aqueous solution that can be used at this time is an aqueous solution whose pH exceeds 7, and as the basic aqueous solution, those exemplified as the basic aqueous solution added simultaneously with the raw material solution can be used without any limitation.

The type of the alcohol and the type of the basic aqueous solution used as a mixed solution with the basic aqueous solution as required are not particularly limited, but from the viewpoint of performing the particle forming reaction uniformly, When alcohol is used as the solvent of the raw material solution, an alcohol of the same type as the alcohol is selected, and as the basic aqueous solution, a basic aqueous solution of the same type as the basic aqueous solution added at the same time as the raw material solution is selected. Is preferred. When used as a mixed solution with a basic aqueous solution, the amount ratio of the alcohol and the basic aqueous solution is not particularly limited, but a quantitative ratio of 0.01 to 5.0 liters of the basic aqueous solution to 1 liter of the alcohol is preferable. It is.

The amount of the alcohol or the mixed solution is not particularly limited as long as it can be stirred and gives a substantially uniform reaction field. What is necessary is just to use the amount which becomes the volume of 0.02-0.2 times the total volume of the said basic aqueous solution.

The conditions for simultaneously adding and reacting the raw material solution and the basic aqueous solution to the mixed solution are not particularly limited. However, while stirring, the addition rates of the raw material solution and the basic aqueous solution are controlled. It is preferred to do so. The method of addition is not particularly limited, and it may be dropped on the liquid surface of alcohol or may be added in alcohol. In addition, since the reaction occurring at this time is an exothermic reaction, it is preferable to carry out the reaction while controlling the temperature. These reaction conditions cannot be determined unconditionally because they vary depending on the solution composition of the raw material solution used, the type and concentration of the basic aqueous solution, etc., but a general stirring speed is in the range of 25 to 1000 rpm. The rate of addition of the raw material solution and the basic aqueous solution to 1 liter of the mixed solution is 1 to 500 m, respectively.
1 / min and 0.1-50 ml / min, and the reaction temperature is 0
~ 80 ° C. By performing the reaction under such reaction conditions, particles having a bond between the tin atom and the second element via an oxygen atom (hereinafter, also referred to as ancestral particles) are formed.

The particles thus formed are separated by filtration or the like, washed, dried, and then heat-treated to become composite oxide particles, and the composite oxide of the present invention is obtained. At this time, it is more preferable to use a non-oxidizing atmosphere such as argon or nitrogen so that divalent tin is not oxidized to tetravalent.

The heat treatment conditions at this time are to remove water, solvent, etc. contained in the separated coarse particles, to promote the bond formation of Sn-OM (where M is the second element), There is no particular limitation as long as the surface hydroxyl groups can be removed. However, the heat treatment temperature is preferably from 200 to 600 ° C., and from 300 to 5 from the viewpoints of high lithium ion occlusion / release amount and good cycle characteristics of the obtained composite oxide.
00 ° C is more preferred.

The firing time varies depending on the firing temperature, atmosphere, etc., but the firing time is preferably 0.03 to 24 hours. The rate of temperature rise during firing is not particularly limited, but is preferably 0.1 to 100 ° C./min.

The atmosphere during firing is not particularly limited as long as divalent tin is not oxidized to tetravalent. For example,
Nitrogen, or an inert atmosphere of argon, helium, neon or the like, or a mixed atmosphere thereof. In some cases, in order to adjust the valence of tin between 0 and 2, or between 0 and 4, hydrogen, A reducing gas atmosphere such as carbon monoxide may be used in combination.However, in the case of a reducing gas atmosphere, the tin oxide is reduced and a large amount of metallic tin is generated inside, or a large amount of organic matter remains and the cycle is reduced. Precise control is required because the characteristics may be degraded.

The composition of the composite oxide finally obtained by the production method of the present invention basically includes the amount and valence state of tin contained in the raw material solution, and the type (including valence state) of the second element. ) And the amount. Therefore, the amount of tin contained in the raw material solution and the type (including the valence state) and amount of the second element may be appropriately determined according to the composition of the composite oxide to be obtained.

The tin-based composite oxide of the present invention thus produced can be suitably used as a negative electrode active material for a non-aqueous electrolyte secondary battery. Batteries are characterized by high capacity and excellent cycle characteristics.

The production of a non-aqueous electrolyte secondary battery using the composite oxide of the present invention as a negative electrode active material can be carried out by a known method, for example, by the following method. .

First, the composite oxide of the present invention is kneaded with a solvent such as N-methylpyrrolidone using a kneader, a mixer or the like to produce a paste. At this time, a conductivity-imparting agent such as graphite or acetylene black, or a binder such as polytetrafluoroethylene or polyvinylidene fluoride may be appropriately added.

After the paste is produced, the current collector is coated, filled or impregnated with the paste, and the solvent is dried and removed.
Pressing, cutting, and the like are performed to form a desired shape to obtain a negative electrode. The negative electrode and the positive electrode manufactured in the same manner are stacked in a strip shape with a separator interposed therebetween, and if the battery is a cylindrical nonaqueous electrolyte secondary battery, it is wound in a columnar shape, and if it is a square nonaqueous electrolyte secondary battery, It is folded to produce an electrode part. Thereafter, the electrode portion is inserted into a desired battery container, a non-aqueous electrolyte is injected, a safety device or the like is inserted, and the can is sealed.

For the positive electrode, the current collector, the non-aqueous electrolyte, the separator, and the like, materials used in conventional non-aqueous electrolyte secondary batteries are used without any problem.

As the positive electrode active material, TiS ₂ , MoS ₂ ,
Chalcogen compounds such as sulfides such as FeS ₂ , selenides such as NbSe ₃ , or Cr ₂ O ₅ , Cr ₃ O ₈ , V
Oxides of transition metals such as ₃ O ₈ , V ₂ O ₅ , V ₆ O ₁₃ , Li
Mn ₂ O ₄ , LiMnO ₂ , LiV ₃ O ₅ , LiNiO ₂ , L
a composite oxide of lithium and a transition metal, such as iCoO ₂ ;
Alternatively, a material capable of occluding and releasing lithium, such as a conjugated polymer such as polyaniline, polyacetylene, polyparaphenylene, polyphenylenevinylene, polypyrrole, or polythiophene, or a crosslinked polymer having a disulfide bond can be used.

As the current collector, a strip-shaped thin plate or mesh made of copper, aluminum, or the like can be used.

Examples of the non-aqueous electrolyte include propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone,
LiClO ₄ , LiPF ₆ may be used alone or in a mixture of two or more kinds of non-aqueous solvents such as tetrahydrofuran, 1,3-dioxolan, 4-methyl-1,3-dioxolan, diethyl ether, sulfolane, methylsulfolane, acetonitrile, propionitrile and the like. , LiAsF ₆ , LiB
F ₄ , LiB (C ₆ H ₅ ) ₄ , LiCl, LiBr, CH _{3
SO 3 Li, CF 3 SO 3} Li nonaqueous electrolyte lithium salt is dissolved, such as can be also be used in any combination.

As the separator, a separator having low resistance to the movement of ions and excellent in solution retention may be used. For example, a polymer pore filter made of polypropylene, polyethylene, polyester, polyflon, or the like, a glass fiber filter, a nonwoven fabric, or a nonwoven fabric made of glass fibers and these polymers can be used. Further, when the temperature inside the battery becomes high, a material that melts to close the pores and prevent short circuit between the positive electrode and the negative electrode is preferable.

For the purpose of reducing the irreversible capacity in the first cycle of the nonaqueous electrolyte secondary battery, lithium for the irreversible capacity can be previously inserted into the negative electrode by a chemical or electrochemical treatment. For example, after attaching a lithium metal sheet to a negative electrode, a battery is produced, and lithium can be inserted into the negative electrode. Alternatively, a lithium metal sheet may be attached to the positive electrode sheet to prepare a battery, and the battery may be discharged by an external circuit to preliminarily insert lithium into the negative electrode. The first irreversible capacity can also be reduced by mixing the composite oxide of the present invention with a negative electrode material which has previously absorbed lithium, such as Li _3-x Co _x N, which has previously been desorbed.

[0073]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 Tetraethoxysilane 41.6 in 920 ml of methanol
7 g (0.2 mol) and 11.38 g of SnCl ₂ (0.0
6 mol) and dissolved under stirring to obtain a transparent homogeneous solution. Under stirring, 500 ml of oxygen per minute was supplied into the solution for 30 minutes to oxidize tin in the solution to tetravalent, and then 500 ml per minute of nitrogen was supplied for 50 minutes, and then SnCl ₂ 2
6.55 g (0.14 mol) was dissolved to prepare a transparent homogeneous solution (hereinafter also referred to as solution A).

On the other hand, 36.43 g of 28% aqueous ammonia was added to 38 g of methanol to obtain a uniform solution (hereinafter also referred to as solution B). At this time, the molar ratio of NH ₃ in Solution B to Cl in Solution A (NH ₃ / Cl) was 1.5.

In a 1-liter three-necked flask in which a pair of nozzles for dropping A droplets and for dropping B droplets were respectively installed on two side tubes,
80 ml of methanol was charged, and the mixture was stirred at 750 rpm using a magnetic stirrer while stirring at 500 rpm.
10 ml of nitrogen into methanol from the inner tube of a three-necked flask.
Minutes. Then, while continuing to stir and supply nitrogen, the solution A and solution B were each supplied to the two pipes using a pair of nozzles at a rate of 2.0 m / nozzle using a tube pump.
The methanol was dropped into the three-necked flask at a dropping rate of 1 / min and 0.18 ml / min. At this time, the temperature of the solution in the three-necked flask was set to 20 ° C. using a water bath. A precipitate was formed with the addition of the solution A and the solution B, and the solution in the three-necked flask became cloudy. After the addition of the solution A and the solution B was completed, stirring and supply of nitrogen were continued for another 30 minutes, and the formed white precipitate was separated by filtration and washed with water. The washed precipitate is dried under vacuum for 100
And dried under an argon atmosphere.
C. for 1 hour to give a pale yellow powder.

When the composition of the obtained powder was analyzed by fluorescent X-ray analysis, the atomic ratio Sn / Si of tin to silicon in the composite oxide constituting the powder was 1.03.

The composition ratio of the minute region by EDS was measured as follows. 10 mg of the sample powder and 5 ml of pure water are put into a sample tube bottle, and are placed in an ultrasonic cleaner filled with 1 liter of water.
Ultrasound was applied for minutes. A grid with a support membrane (carbon-reinforced collodion membrane,
(Cu150 mesh), the liquid remaining on the grid was sucked with a filter paper and air-dried to obtain an analysis sample. Field emission transmission electron microscope (Philips Electr)
The powder particles are irradiated with an electron beam at an acceleration voltage of 200 kV and a sample inclination angle α = + 20 ° using Tecnai F20 (manufactured by Optics Inc.) and an energy dispersive X-ray analyzer (Norman) is used. I
NANTENT (VANTAGE), and the intensity was measured. The intensity ratios A and B of the characteristic X-rays are
The intensity of the tin Lα1 ray (S) measured with the beam diameter of the electron beam applied to the powder as 3 nm and 50 nm, respectively.
n (Lα1)) with respect to the intensity (Si
(Kα)) ratio (Si (Kα)) / (Sn (Lα1))
A / B was calculated from these. When the measurement was performed in ten randomly selected regions in the sample, the A / B calculated from the obtained intensity ratios A and B was 0.6 to 0.6.
It was in the range of 1.7, and was the composite oxide of the present invention.
Table 1 shows the minimum and maximum values of the obtained A / B. FIG. 1 shows a TEM bright-field image of the obtained composite oxide.

[0079]

[Table 1] Using the obtained powder as a negative electrode active material, a lithium ion battery was produced, and the charge / discharge capacity and cycle characteristics of the obtained lithium ion battery were evaluated. The production of the lithium ion battery and the evaluation of the initial charge / discharge capacity and the cycle characteristics were performed as follows.

Preparation of Lithium-ion Battery:
Composite oxide powder, polyvinylidene fluoride (binder) and
Acetylene black (conductivity imparting agent)
(Weight ratio) and mixed with 500 mg of this mixture.
Then, 1 ml of N-methylpyrrolidone is added and kneaded.
And then apply it to copper foil and vacuum dry at 100 ° C.
After drying in a dryer for 24 hours, it was rolled to obtain a negative electrode. Non-water
The electrolyte is LiPF ₆(Concentration of 1 mol / liter)
Equal volume of ethylene carbonate and diethyl carbonate
Use lithium metal dissolved in a mixed solvent
As a result, a coin-type battery was produced.

Measurement of charge / discharge capacity: Using a charge / discharge device (manufactured by Hokuto Denko), a charge / discharge cycle test of the simple lithium battery was performed, and a discharge time t (unit: time) was measured to obtain a negative electrode active material. Was measured. The charge / discharge cycle test was performed at a current value (constant) corresponding to 48 mA / g, and the charge / discharge was performed within a range of 0 to 1.0 V.
The charge / discharge capacity was calculated as an amount per unit weight of the active material added to the paste. That is, the calculation was performed assuming that the charge / discharge capacity of acetylene black as the conductivity imparting agent was 0. Table 1 also shows the discharge capacity at the first cycle and the 20th cycle.

[0082] Example 2 Methanol 930ml the zirconium oxychloride octahydrate _{(ZrOCl 2 · 8H 2 O)} 64.45g (0.2 mol) and SnCl ₂ 11.38 g (0.06 mol) was added,撹is The solution was dissolved under a vacuum to obtain a clear homogeneous solution. Under stirring, 500 ml of oxygen per minute was supplied into this solution for 30 minutes to oxidize tin in the solution to tetravalent, and then 500 ml of nitrogen per minute was supplied for 50 minutes, followed by 26.55 g of SnCl ₂ .
(0.14 mol) was dissolved to prepare a transparent homogeneous solution (hereinafter also referred to as solution A).

On the other hand, 72.86 g of 28% aqueous ammonia was added to 5 g of methanol, and a homogeneous solution (hereinafter, also referred to as solution B) was added.
I got At this time, NH in solution B with respect to Cl in solution A
₃ mole ratio of (NH ₃ / Cl) was 1.5.

Thereafter, the same operation as in Example 1 was performed to obtain a pale yellow composite oxide powder. When the composition of the obtained powder was analyzed by X-ray fluorescence analysis, the atomic ratio of tin to zirconium in the composite oxide constituting the powder, Sn /
Zr was 0.98. Evaluation of the mixed state of tin and zirconium in the obtained powder was performed in the same manner as in Example 1 using TEM and EDS. However, the intensity ratios A and B of the characteristic X-rays are set so that the beam diameter of the electron beam irradiating the powder is 3
Kα1 of zirconium relative to the intensity of the tin Lα1 line (Sn (Lα1)), measured as nm and 50 nm
Ratio of line intensity (Zr (Kα1)) (Zr (Kα1)) /
(Sn (Lα1)), and A / B was calculated from these values. The calculated A / B was in the range of 0.6 to 1.7, and was the composite oxide of the present invention. Table 1 also shows the minimum and maximum values of the obtained A / B. Example 1
A lithium battery was prepared in the same manner as described above, and the charge / discharge capacity was measured. Table 1 also shows the discharge capacity at the first cycle and the 20th cycle.

Comparative Examples 1 and 2 The same procedure as in Example 1 was carried out except that the amounts of the 28% aqueous ammonia added to the solution B were 24.29 g and 29.14 g, respectively, and 13 ml and 8 ml of pure water were added to the solution B, respectively. I went to. At this time, the molar ratio of NH _{3 in} the solution B to Cl in the solution A (NH ₃ / Cl) was 1.0 and 1.2, respectively. The atomic ratio Sn / Si of tin and silicon of the obtained composite oxide was 0.97 and 1.06, respectively. Table 1 also shows the A / B value, the first cycle, and the 20th cycle discharge capacity of the obtained composite oxide. FIG. 2 shows a bright field image of the composite oxide obtained in Comparative Example 1 by a transmission electron microscope.

As shown in Table 1, in the comparative example, the discharge capacity in the 20th cycle was 52% or less of the discharge capacity in the first cycle, whereas in the example, the discharge capacity was 20%.
The discharge capacity at the cycle is 95 times the discharge capacity at the first cycle.
%, Which indicates that the cycle characteristics are good.

[0087]

By using the composite oxide of the present invention as a negative electrode active material for a non-aqueous electrolyte secondary battery, a battery having high capacity and excellent cycle characteristics can be manufactured.

[Brief description of the drawings]

FIG. 1 is a transmission electron micrograph showing the structure of a composite oxide particle obtained in Example 1.

FIG. 2 is a transmission electron micrograph showing the structure of the composite oxide particles obtained in Comparative Example 1.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 10/40 H01M 10/40 Z F Term (Reference) 4G048 AA06 AB02 AC06 AD03 AE06 4G072 AA50 GG02 HH28 JJ28 LL02 LL09 LL11 MM21 MM36 UU30 5H029 AJ03 AJ05 AK02 AK03 AK05 AK16 AL03 AM02 AM03 AM04 AM05 AM07 5H050 AA07 AA08 BA17 CB03 EA02 EA30

Claims (5)

[Claims] 1. A tin-based composite oxide containing tin and at least one second element capable of forming a composite oxide with tin, wherein the tin-based composite oxide has a cross-sectional area of 9 to 25 nm ² in the composite oxide. Wherein the composition of the fine region is substantially the same as the average composition of the entire composite oxide. 2. A tin-based composite oxide containing tin and at least one second element capable of forming a composite oxide with tin, wherein an arbitrary region of the composite oxide has an analysis region diameter of 3
The intensity ratio of characteristic X-rays of tin and the second element in each analysis region measured when performing energy dispersive X-ray spectroscopy using a transmission electron microscope under the conditions of ~ 5 nmφ and 50 nmφ, If B, A / B is 0.
A tin-based composite oxide, which is 6 to 1.7. 3. A raw material solution obtained by dissolving a tin halide and at least one organic solvent-soluble compound containing at least one second element capable of forming a composite oxide with tin in an organic solvent, The aqueous solution is added to an alcohol at the same time to react to precipitate a solid, and the deposited solid is heat-treated to produce a tin-based composite oxide, wherein the molar ratio of the basic compound contained in the aqueous solution of the basic compound is The method for producing a tin-based composite oxide according to claim 1 or 2, wherein the number is set to 1.3 to 1.6 times the number of moles of all halogen atoms contained in the raw material solution. 4. A negative electrode active material for a non-aqueous electrolyte secondary battery, comprising the tin-based composite oxide according to claim 1 or 2. 5. A non-aqueous electrolyte secondary battery using the negative electrode active material according to claim 4.