JPH10273321A - Method for producing tin oxide powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable control of both the composition and microstructure of tin oxide powder as important factors for improving performances of nonaqueous electrolyte secondary battery, by dispersing a specific organic solvent soluble compound in an organic solvent to give a precursor solution, gelatinizing and baking the gel. SOLUTION: An organic solvent-soluble tin compound and/or metal tin and at least one soluble compound selected from the group consisting of an organic solvent-soluble alkaline earth metal, an organic solvent-soluble rare earth element compound, an organic solvent-soluble transition element compound, organic solvent-soluble element compounds of the groups 13-15 of the periodic table (except the organic solvent-soluble tin compound) and an organic solvent-soluble chalcogen element compound are dissolved in an organic solvent such as an alcohol, acetone or acetonitrile to give a precursor solution. The solution is concentrated to dryness to give a gel, which is baked at 250-1,200 deg.C, preferably 50-1,100 deg.C for 0.03-8 hours to give tin oxide powder having 10-150 m<2> /g specific surface area and 1-30 nm particle diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing tin oxide powder and a nonaqueous electrolyte secondary battery using the tin oxide powder produced by the method as a negative electrode active material for a nonaqueous electrolyte secondary battery. .

[0002]

2. Description of the Related Art As a power source for portable devices such as mobile phones, portable terminals, and video cameras, which are rapidly spreading today, or as a power source for electric vehicles, there is a social demand for a small, lightweight, and high energy density secondary battery. The demands are getting stronger.

[0003] Among secondary batteries that can be charged and used repeatedly, secondary batteries such as lead-acid batteries, nickel-cadmium batteries, and nickel-hydrogen batteries that use aqueous electrolytes, except for lead-acid batteries with high overvoltages, use water. A high battery voltage exceeding the decomposition voltage cannot be obtained. On the other hand, since the nonaqueous electrolyte secondary battery uses a nonaqueous solvent for the electrolyte, a higher battery voltage can be obtained than the above-described secondary battery using an aqueous electrolyte. For this reason, non-aqueous electrolyte secondary batteries have a high energy density and can be reduced in size and weight, and demand is rapidly growing as a power source for portable devices. Therefore, further improvement in battery performance, that is, charge / discharge capacity is required.

[0004] Non-aqueous electrolyte secondary batteries occlude lithium,
A positive electrode composed of a positive electrode active material capable of releasing and a current collector, a negative electrode composed of a negative electrode active material capable of inserting and extracting lithium and a current collector, and a lithium salt in a non-aqueous solvent It is composed of a dissolved electrolyte, a separator, a battery container, and the like. In such a secondary battery, lithium released from the positive electrode active material during charging is occluded in the negative electrode active material, and lithium discharged from the negative electrode active material on the contrary during discharging is occluded in the positive electrode active material. You.

As a negative electrode active material suitable for a non-aqueous electrolyte secondary battery having a high charge / discharge capacity, it is desirable to use metallic lithium containing the largest amount of lithium per unit weight, focusing only on the energy density. . However, when lithium metal is used as the negative electrode active material, lithium is not uniformly deposited on the surface of the negative electrode during charging but is deposited in a dendritic manner, which penetrates through the separator and short-circuits the negative electrode and the positive electrode. There is. In addition, there is a problem in that metallic lithium precipitated in a dendritic form falls off the negative electrode and the charge / discharge cycle life is shortened. Due to these problems, metallic lithium has not been put to practical use as a negative electrode active material, though it has the highest theoretical lithium capacity involved in the battery reaction.

At present, as a negative electrode active material of a commercially available non-aqueous electrolyte secondary battery, a carbon material having a relatively high crystallinity represented by graphite (hereinafter, also referred to as a graphite material), a non-graphitizable carbon, etc. Carbon materials having a relatively low crystallinity (hereinafter also referred to as non-graphitizable carbon materials) are used.

When a graphite material is used as a negative electrode active material of a non-aqueous electrolyte secondary battery (hereinafter also referred to as a negative electrode active material), the negative electrode potential is stabilized at a substantially constant value from the beginning to the end of the discharge. A stable battery voltage can be secured until the end. However, the charge / discharge capacity of the graphite material is up to 372 mAh / g in theoretical value, and actually 280 to 33
It is about 0 mAh / g. Therefore, in order to produce a nonaqueous electrolyte secondary battery having a higher energy density, a negative electrode active material having a higher charge / discharge capacity is desired.

On the other hand, the non-graphitizable carbon material has a charge / discharge capacity of 400 to 700 mAh / g, and in this respect, has characteristics superior to those of the graphite material. However, in non-graphitizable carbon materials, since the negative electrode potential continues to rise from the beginning of discharge,
When used for a non-aqueous electrolyte secondary battery, the battery voltage keeps decreasing with discharge. Therefore, despite the fact that sufficient releasable lithium still remains in the non-graphitizable carbon, which is the negative electrode active material, further discharge occurs at a low voltage and cannot be used as a power source. There is. As a result, the charge / discharge capacity that can be substantially used may be only about 300 mAh / g, which is almost the same as that of the graphite material.

In recent years, tin oxide-based materials have attracted attention as a material having a high charge / discharge capacity. In the case of tin oxide-based materials, SnO or SnO
₂ , a high discharge capacity of 500 to 600 mAh / g was found (JP-A-6-275268, JP-A-7-122274, etc.). Then, a Sn-Li-O-based material (JP-A-7-201318), a Sn-Si-O-based material (JP-A-7-230800), or a Sn-MO-based material (M is an alkaline earth metal, Tables 13, 14, 1
A tin oxide-based material having a composition such as a group V element or zinc, and JP-A-7-288123) has been proposed.

[0010] In these tin oxide-based materials, the charge-discharge cycle characteristics are somewhat improved, but the discharge capacity tends to decrease as compared with SnO or SnO _2, and none of them is still sufficient. . For example, Li _x Sn
The discharge capacity of O is 300 mAh / g or less (estimated from the capacity of the battery), and Li ₂ SnO ₃ , Li ₂
442 mAh / g for SnO ₂ and 493 mAh / g for amorphous SnSiO ₃ produced by the melting method.
Ah / g, and these discharge capacities are all SnO
Alternatively, it is equal to or less than SnO ₂ .

In order to improve the charge / discharge capacity of the tin oxide-based material, it is extremely important to control the fine structure such as the specific surface area of the tin oxide-based material in addition to the control of the composition as described above. Was found to be. Conventionally, the importance of the influence of the microstructure on the charge / discharge capacity has not been recognized,
No optimization of the microstructure has been attempted.

The present inventors have reported that the specific surface area is 10 to 150 m ² /
g, and the volume of pores having an average pore radius of 0.05 to 25 nm is 0.1 to 0.5 cm ³ / g, and the volume of such pores accounts for 70% or more of the whole, In addition, it has been found that tin oxide powder having a fine structure having a crystallite size of 1 to 30 nm exhibits particularly excellent charge / discharge capacity. The fine structure of the tin oxide powder having such excellent charge / discharge capacity is largely affected mainly by the content of the second component element contained in the tin oxide powder and the heat treatment temperature.
Therefore, in order to obtain a tin oxide powder having a high charge / discharge capacity, a manufacturing method capable of adding various second component elements and performing heat treatment and firing over a wide temperature range is adopted. It is essential to optimize the microstructure of the tin powder. However, there has been no manufacturing method capable of optimizing the fine structure in the conventional manufacturing method. Conventionally, the production of tin oxide powder has been mainly performed by a solid phase reaction method or a solution method. In the case of producing tin oxide powder to which the second component element is added by the solid-phase reaction method, after mixing the powdered tin oxide and the oxide of the second component element to be contained in the tin oxide in a solid phase, 700 to It is manufactured by baking at 1000 ° C. for about 12 hours (for example, JP-A-7-288123 or JP-A-7-230800). In general, it is difficult to uniformly mix the raw materials in the solid-phase mixing, so that in order for tin oxide to react with an oxide of the second component element, the element needs to diffuse in the solid over a long distance. . for that reason,
The reaction between tin oxide and the oxide of the second component element requires firing at a high temperature for a long time as described above. However, in practice, even in such a solid-phase reaction, no matter how long the reaction is carried out at a high temperature, inhomogeneous composition is generally unavoidable. Moreover, the tin oxide powder obtained by the reaction at high temperature for a long time undergoes crystal growth, grain growth or densification.
It is very difficult to control its microstructure. As a result, only a material having a low charge / discharge capacity was obtained as the negative electrode active material used for the nonaqueous electrolyte secondary battery.

On the other hand, as a method for producing tin oxide powder by a solution method, a method of neutralizing an aqueous solution of tin chloride with ammonia or the like to obtain a white precipitate (α-stannic acid) and calcining the same is well known. (Fine Ceramics Encyclopedia, Edited by the Fine Ceramics Encyclopedia, p. 264, published by Gijudo, 1987). According to this method, it is easily estimated that tin oxide powder containing the second component element can be finally obtained by dissolving the chloride of the second component element in the aqueous solution of tin chloride and then adding an alkali. . However, in the above-mentioned solution method, the precipitation is controlled by the pH of the aqueous solution. However, since the pH of the solution causing the precipitation varies depending on the substance, it is necessary to obtain a precipitate in which tin and the second component element are uniformly mixed in the charged composition. Was very difficult. Therefore, in order to obtain a tin oxide powder having a uniform composition, firing at the same high temperature as in the above-described solid-phase reaction method was required, and the fine structure could not be controlled.

As described above, according to the conventionally known method for producing a tin oxide powder containing the second component element, both the composition and the fine structure, which are important factors for improving the performance of the nonaqueous electrolyte secondary battery, are improved. It was extremely difficult to control.

[0015]

Accordingly, there is provided a method for producing a tin oxide powder capable of controlling both the composition and the fine structure of the tin oxide powder, which are important factors for improving the performance of the nonaqueous electrolyte secondary battery. Development was required.

[0016]

Means for Solving the Problems The present inventor has conducted intensive studies from various angles to solve the above-mentioned problems. as a result,
After dissolving the organic solvent-soluble compound of tin and the second component element in the organic solvent, the solution is gelled, and the tin oxide powder produced by baking suppresses the composition fluctuation of the second component element, and The inventors have found that the fine structure of the powder can be controlled, and have now completed the present invention.

That is, the present invention relates to an organic solvent-soluble tin and / or metallic tin, an organic solvent-soluble alkaline earth metal compound, an organic solvent-soluble rare earth element compound, an organic solvent-soluble transition element compound, and an organic solvent-soluble periodic table. At least one member selected from the group consisting of a group 14 element compound, an organic solvent-soluble periodic table group 14 element compound (excluding an organic solvent-soluble tin compound), an organic solvent-soluble periodic table group 15 element compound, and an organic solvent-soluble chalcogen element compound. A method for producing a tin oxide powder, comprising: dissolving a soluble compound in an organic solvent to form a precursor solution, forming a gel from the precursor solution, and then firing the gel.

[0018] Preferably, at least one selected from the group consisting of tin halides and / or metallic tins, and transition elements, halides or alkoxides of Group 13 elements, Group 14 elements and Group 15 elements of the periodic table. A method for producing a tin oxide powder, comprising: dissolving a compound soluble in an organic solvent in an organic solvent to form a precursor solution; forming a gel from the precursor solution; and firing the gel.

The production method of the present invention has a specific surface area of 10
１５０150 m ² / g, the volume of pores having an average pore radius of 0.05 to 25 nm is 0.1 to 0.5 cm ³ / g.
g, and the volume of such pores occupies 70% or more of the whole, and is suitable as a method for producing a tin oxide powder having a fine structure in which the crystallite size is 1 to 30 nm.

Another aspect of the present invention is a negative electrode active material for a non-aqueous secondary battery, comprising the tin oxide powder obtained by the above-mentioned production method.

Still another aspect of the present invention is directed to a negative electrode obtained by bonding the negative electrode active material for a non-aqueous electrolyte secondary battery to a current collector, and a positive electrode active material comprising a material capable of inserting and extracting lithium ions. A non-aqueous electrolyte secondary battery characterized in that a positive electrode formed by bonding a non-aqueous electrolyte to a current collector is housed in a battery container together with a non-aqueous electrolyte through a separator.

Hereinafter, the present invention will be described specifically.

In the method for producing tin oxide powder of the present invention, first, an organic solvent-soluble tin compound and / or metallic tin, and an organic solvent-soluble alkaline earth metal compound, an organic solvent-soluble rare earth element compound, and an organic solvent-soluble transition element compound , An organic solvent soluble periodic table group 13 element compound,
At least one soluble compound selected from the group consisting of an organic solvent soluble periodic table group 14 element compound (excluding organic solvent soluble tin compounds), an organic solvent soluble periodic table group 15 element compound, and an organic solvent soluble chalcogen element compound ( Hereinafter, a precursor solution in which an organic solvent-soluble compound is dissolved in an organic solvent is prepared.

In the present invention, the organic solvent used for preparing the precursor solution is not limited as long as it can dissolve an organic solvent-soluble tin compound, metal tin and an organic solvent-soluble compound described below. Examples of such an organic solvent include alcohol, acetone, acetonitrile, and the like, and a mixture thereof, and usually an alcohol is mainly used.

Specific examples of these alcohols include methanol (also called methyl alcohol), ethanol (also called ethyl alcohol), propanol (also called propyl alcohol), butanol (also called butyl alcohol), octanol (octyl alcohol), Methoxyethanol, 2-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 preferred because of high solubility of the organic solvent-soluble compound, and methanol is more preferred because it is inexpensive and easily available. The above-mentioned alcohol is usually used alone, but a mixture of two or more alcohols may be used to control the reactivity and solubility with the organic solvent-soluble compound.

The organic solvent-soluble tin compound (hereinafter also referred to as a tin compound) used in the present invention includes tin halide, organotin, tin alkoxide and the like. The halogens in the tin halide are Cl, Br, I, and F atoms. Hydrates may also be used.

Of these compounds, tin halide is more preferably used from the viewpoint of cost and stability. Of the tin halides, tin chloride and tin bromide are particularly preferred.
Specifically, SnCl ₂ , SnCl ₂ · 2H ₂₀ , SnB
r ₂ , SnI ₂ , SnF _{2 and the} like.
l ₂ , SnBr ₂ and SnCl ₂ .2H ₂ O are preferably used. Further, the tin halide compound modified with an organic compound, for example, Sn (CH ₃ ) ₂ Cl ₂ can also be used.

As the organic tin compound, (CH ₃ ) ₂ Sn,
(C ₂ H ₅ ) ₂ Sn, (C ₃ H ₇ ) ₄ Sn or the like can be used or contained in such a range that it can be dissolved. Examples of tin alkoxides include Sn (OC ₂ H ₅ ) ₄ , Sn (OC ₃ H ₇ ) ₄ ,
Sn (OC ₄ H ₉ ) _{4 and the} like can be mentioned. Further, a mixture of two or more kinds of the tin compounds may be used.

The shape of the metallic tin used in the present invention is not particularly limited, and examples thereof include a plate, a bar, a sheet, a granule, a powder, a sand, a flower, and a lump. From the point of view, granules, powders and sands are preferred. The purity is preferably higher, but is not particularly limited as long as it does not affect the battery reaction and further the battery performance.

The ratio of the organic solvent to the tin compound and / or metal tin in preparing the precursor solution is not particularly limited as long as the tin compound and / or metal tin are uniformly dissolved in the organic solvent. However, if there is too little organic solvent,
The tin compound and / or metal tin are not completely dissolved, leaving insolubles, and a uniform precursor solution cannot be obtained. When the amount of the organic solvent is too large, the dissolution rate of the tin compound and / or the metal tin increases, but it takes time for the subsequent concentration. Therefore, although the ratio varies depending on the type of the organic solvent and the tin compound and / or the metal tin used, the ratio is preferably such that the amount of the organic solvent is 2 to 1000 times in molar ratio with respect to tin in terms of element. It is desirable that the ratio be 5 to 500 times. When using only metal tin as a tin source,
It is preferable to add a hydrogen halide gas such as hydrogen chloride, hydrochloric acid, or the like because the dissolution rate of metal tin in an organic solvent increases.

The amount of metallic tin is not particularly limited as long as it is within the range of dissolving in each charged composition. However, if the amount of metallic tin is too large, it takes a long time to dissolve or may remain undissolved. Therefore, when a tin halide compound is used as the tin compound, the dissolved metallic tin and the tin halide compound The ratio of the number of halogen atoms to the total amount of tin is 0.60 or more.
It is preferable to determine the amount of dissolved tin so as to be less than 80.

The tin oxide powder contains at least one element selected from the group consisting of an alkaline earth metal, a rare earth element, a transition element, an element belonging to Groups 13, 14, and 15 of the periodic table, and a chalcogen element (hereinafter referred to as a second component). Element or an oxide thereof (such a tin oxide powder is hereinafter also referred to as a composite tin oxide powder), an alkoxide or halide containing a desired second component element as an organic solvent-soluble compound , Oxychloride, nitrate, acetate, sulfate, or ammonium salt with a tin compound and / or
Alternatively, the precursor solution is dissolved in an organic solvent together with metal tin.

When the second component element is an alkaline earth metal, halides and hydrates of the alkaline earth metal, nitrates and hydrates thereof, alkoxides and the like can be used.
It can be used without any particular limitation.

Specific compounds include CaCl ₂ , Ca
Br ₂ , CaI ₂ , CaCl ₂ .6H ₂ O, CaBr ₂ .6
_{H 2 O, CaI 2 · 6H} 2 O, Ca (NO 3) 2 · 4H 2 O,
Ca (NO ₃ ) ₂ .xH ₂ O, Ca (OCH ₃ ) ₂ , Ca
(OC ₂ H ₅ ) ₂ , Ca (OC ₃ H ₇ ) ₂ , Ca (OC ₄ H ₉ )
₂ , SrCl ₂ , SrBr ₂ , SrI ₂ , SrCl ₂ .6H ₂
O, SrBr ₂ .6H ₂ O, SrI ₂ .6H ₂ O, Sr (N
O ₃ ) ₂ , Sr (OCH ₃ ) ₂ , Sr (OC ₂ H ₅ ) ₂ , Sr
(OC ₃ H ₇ ) ₂ , Sr (OC ₄ H ₉ ) ₂ , BaCl ₂ , Ba
Br ₂ , BaI ₂ , BaCl ₂ .2H ₂ O, BaBr ₂ .2
H ₂ O, BaI ₂ · 2H ₂ O, Ba (NO ₃ ) ₂ , Ba (O
CH ₃ ) ₂ , Ba (OC ₂ H ₅ ) ₂ , Ba (OC ₃ H ₇ ) ₂ , B
a (OC ₄ H ₉ ) ₂ and the like.

When the second component element is a rare earth element, halides and hydrates of the rare earth elements, nitrates and hydrates thereof, alkoxides and the like can be used without any particular limitation.

As specific compounds, LaCl ₃ , La
Br ₃ , LaI ₃ , LaCl ₃ .7H ₂ O, La (NO ₃ ) ₃
6H ₂ O, La (OCH ₃ ) ₃ , La (OC ₂ H ₅ ) ₃ , L
a (OC ₃ H ₇ ) ₃ , CeCl ₃ , CeBr ₃ , CeI ₃ , C
_{eCl 3 · 6H 2 O, Ce} (NO 3) 3 · 6H 2 O, PrC
l ₃ , PrCl ₃ .7H ₂ O, Pr (NO ₃ ) ₃ .6H ₂ O,
Pr (OC ₃ H ₇ ) ₃ , NdCl ₃ , NdBr ₃ , NdCl ₃
・ 6H ₂ O, Nd (NO ₃ ) ₃・ 5H ₂ O, SmCl ₃・ x
H ₂ O, Sm (NO ₃ ) ₃ .xH ₂ O, Sm (OC
_{3 H 7) 3, EuCl 3} · 6H 2 O, Eu (NO 3) 3 · 6H 2
_{O, GdCl 3, GdCl 3 ·} 6H 2 O, Gd (NO 3) 3
_{· 5H 2 O, TbCl 3,} TbCl 3 · xH 2 O, Tb (N
O ₃ ) ₃ .xH ₂ O, DyCl ₃ , DyCl ₃ .xH ₂ O, D
_{y (NO 3) 3 · 5H} 2 O, Dy (OC 3 H 7) 3, HoCl
_{3, HoCl 3 · 6H 2 O} , Ho (NO 3) 3 · 5H 2 O, Er
_{Cl 3 · 6H 2 O, Er} (NO 3) 3 · 5H 2 O, Er (O
_{C 3 H 7) 3, TmCl} 3 · 6H 2 O, Tm (NO 3) 3 · 5
_{H 2 O, YbBr 3, YbI} 3, YbCl 3 · 6H 2 O, Y
b (NO ₃ ) ₃ .xH ₂ O, LuCl ₃ , Lu (NO ₃ ) _3.
xH ₂ O and the like can be exemplified.

When the second component element is a transition element,
Transition element halides and hydrates, oxyhalides, acetates, nitrates and hydrates thereof, sulfates and hydrates thereof, ammonium salts, alkoxides of transition elements and the like are used without particular limitation. be able to.

As specific compounds, ScCl ₃ , Sc
_{Cl 3 · xH 2 O, Sc} (NO 3) 3 · xH 2 O, TiC
l ₄ , TiBr ₄ , Ti (OCH ₃ ) ₂ , Ti (OC ₂ H ₅ )
₂ , Ti (OC ₃ H ₇ ) ₂ , Ti (OC ₄ H ₉ ) ₂ , VBr ₃ ,
VCl ₂ , VCl ₃ , VCl ₄ , VOBr ₂ , VOBr ₃ ,
_{VOCl 3, VF 3, VF 4} , VF 5, VI 3 · 6H 2 O, V
O (OCH ₃ ) ₃ , VO (OC ₂ H ₅ ) ₃ , VO (OC
_{3 H 7) 3, VO (} OC 4 H 9) 3, CrCl 3, CrBr 3,
_{CrCl 3 · xH 2 O, CrBr} 3 · 6H 2 O, CrI 3 ·
xH ₂ O, Cr (CH ₃ COO) ₃ .xH ₂ O, MnC
l ₂ , MnBr ₂ , MnI ₂ , MnCl ₂ .4H ₂ O, Mn
_{Br 2 · 4H 2 O, MnI} 2 · 4H 2 O, Mn (NO 3) 2 ·
6H ₂ O, Mn (OC ₃ H ₇ ) ₂ , Mn (OC ₂ H ₅ ) ₂ , F
eBr ₂ , Fe ₂ Br · 6H ₂ O, FeBr ₃ , FeBr ₃
6H ₂ O, Fe (OH) (CH 3 COO) ₂ , FeCl
_{2, FeCl 3 · 6H 2 O} , FeCl 3, FeI 2, Fe
_{(NO 3) 3 · 9H 2} O, (NH 4) 2 Fe (SO 4) 2 · x
H ₂ O, (NH ₄ ) Fe (SO ₄ ) ₂ .xH ₂ O, Fe (O
CH ₃ ) ₃ , Fe (OC ₂ H ₅ ) ₃ , Fe (OC ₃ H ₇ ) ₃ , F
e (OC ₄ H ₉ ) ₃ , CoBr ₂ , CoBr ₂ .6H ₂ O, C
o (C ₂ H ₃ O ₂ ) ₂ .4H ₂ O, CoCl ₂ , CoCl _{2.
6H 2 O, CoI 2, Co} (NO 3) 2 · 6H 2 O, Co
(OC ₃ H ₇ ) ₂ , NiBr ₂ , NiBr ₂ .xH ₂ O, Ni
(CH ₃ COO) ₂ .xH ₂ O, NiCl ₂ , NiCl _{2.
6H 2 O, NiI 2, NiI} 2 · 6H 2 O, Ni (NO 3) 2
6H ₂ O, CuBr, CuBr ₂ , Cu (CH ₃ CO
_{O) 2, CuCl, CuCl 2} , CuCl 2 · 2H 2 O, C
u (NO ₃ ) ₂ .3H ₂ O, ZnBr ₂ , Zn (CH ₃ CO
_{O) 2 · 2H 2 O,} ZnCl 2, ZnI 2, Zn (NO 3) 2
6H ₂ O, Zn (OCH ₃ ) ₂ , Zn (OC ₂ H ₅ ) ₂ , Z
n (OC ₃ H ₇ ) ₂ , Zn (OC ₄ H ₉ ) ₂ , YBr ₃ , YC
_{l 3 · 6H 2 O, YCl} 3, Y (NO 3) 3 · 6H 2 O, Y
(OCH ₃ ) ₃ , Y (OC ₂ H ₅ ) ₃ , Y (OC ₃ H ₇ ) ₃ , Z
rBr ₄ , ZrCl ₄ , ZrI ₄ , ZrO (CH ₃ COO)
_{2, ZrOCl 2 · 8H 2 O} , ZrI 2 · xH 2 O, ZrO
_{(NO 3) 2 · 2H 2} O, Zr (SO 4) 2 · 4H 2 O, Zr
(OCH ₃ ) ₄ , Zr (OC ₂ H ₅ ) ₄ , Zr (OC
_{3 H 7) 4, Zr (} OC 4 H 9) 4, NbCl 5, NbOC
_{l 3, NbBr 5, NbF 5} , Nb (OCH 3) 5, Nb
(OC ₂ H ₅ ) ₅ , Nb (OC ₃ H ₇ ) ₅ , Nb (OC ₄ H ₉ )
₅ , MoBr ₂ , MoBr ₃ , MoCl ₅ , (NH ₄ ) ₆ Mo
_{7 O 24 · 4H 2 O,} Mo (OC 2 H 5) 5, RuCl 3 · H 2
_{O, PdCl 2 · 2H 2 O} , AgNO 3, CdBr 2 · 4H
_{2 O, CdBr 2, CdCl 2} · 5 / 2H 2 O, CdC
l ₂ , CdF ₂ , CdI ₂ , Cd (NO ₃ ) ₂ .4H ₂ O, H
_{fCl 4, HfOCl 2 · 8H 2} O, Hf (OCH 3) 4,
Hf (OC ₂ H ₅ ) ₄ , Hf (OC ₃ H ₇ ) ₄ , Hf (OC ₄
H ₉ ) ₄ , TaCl ₅ , TaBr ₅ , Ta (OCH ₃ ) ₅ , T
a (OC ₂ H ₅ ) ₅ , Ta (OC ₃ H ₇ ) ₅ , Ta (OC
_{4 H 9) 5, WCl 5} , WCl 6, WBr 6, W (OC 2 H 5)
₅ , W (OC ₃ H ₇ ) ₅ , ReCl ₃ , ReCl ₅ , OsCl
₃ , IrCl ₃ .3H ₂ O, IrCl ₃ , IrCl ₄ , Pt
_{Cl 4 · 5H 2 O, H} 2 PtCl 6 · nH 2 O, AuBr 3 ·
_{xH 2 O, AuCl 3 · xH} 2 O, AuHCl 4 · 4H
_{2 O, Hg 2 Br 2,} HgCl 2, Hg (NO 3) 2 · 2H 2
O, HgSO _{4 and the} like can be exemplified.

When the second component element is a group 13 element of the periodic table, halides and hydrates, ammonium salts, sulfates, organic acid salts, alkoxides, etc. of the group 13 elements of the periodic table are particularly preferred. It can be used without limitation.

As specific compounds, B ₂ O ₃ , (N
_{H 4) 2 O · 5B 2} O 3 · 8H 2 O, BCl 3, BBr 3, B
I 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 , AlC
_{l 3 · 6H 2 O, AlCl} 3, AlI 3, Al (NO 3) 3 ·
9H ₂ O, Al ₂ (SO ₄ ) ₃ , Al ₂ (SO ₄ ) ₃ .nH
₂ O, Al (OCH ₃ ) ₃ , Al (OC ₂ H ₅ ) ₃ , Al (O
C ₃ H ₇ ) ₃ , Al (OC ₄ H ₉ ) ₃ , GaBr ₃ , GaCl ₃ , G
aI ₃ , Ga (NO ₃ ) ₃ .xH ₂ O, Ga ₂ (SO ₄ ) ₃ ,
Ga ₂ (SO ₄ ) ₃ .xH ₂ O, Ga (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, In
I ₃ , In (NO ₃ ) ₃ .xH ₂ O, In ₂ (SO ₄ ) ₃ , I
n ₂ (SO ₄ ) ₃ .xH ₂ O, In (OCH ₃ ) ₃ , In (O
C 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 second component element is a Group 14 element of the periodic table, halides and hydrates, ammonium salts, sulfates, organic acid salts, alkoxides and the like of the Group 14 elements are particularly preferred. It can be used without limitation. Specific compounds include GeBr ₄ , GeCl ₄ ,
GeI ₄ , Ge (OCH ₃ ) ₄ , Ge (OC ₂ H ₅ ) ₄ , Ge
(OC ₃ H ₇ ) ₄ and Ge (OC ₄ H ₉ ) ₄ can be exemplified.

When silicon is contained as the second component element, the general formulas Si (OR _A ) ₄ and R _B Si (OR _A )
_3, R _B R _C Si silicon alkoxide represented by (OR _{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, and a pentyl group; an ethenyl group, a propenyl group, a butenyl group, and a pentenyl group. A linear or branched alkenyl group such as a group, and an aryl group such as a phenyl group.

Specific examples of silicon alkoxides include:
Tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, phenyltrimethoxysilane, propyltrimethoxysilane, n
-Butyltrimethoxysilane, isobutyltrimethoxysilane, n-hexyltrimethoxysilane, n-octadecyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, amyltriethoxysilane, phenyltriethoxysilane, n-octyltriethoxysilane Silane, n-octadecyltriethoxysilane, n-dodecyltriethoxysilane, methyltributoxysilane, ethyltributoxysilane, ethyltripropoxysilane, vinyltriethoxysilane, allyltriethoxysilane, diphenyldimethoxysilane, dimethyldiethoxysilane, Examples include vinylmethyldiethoxysilane, diethyldimethoxysilane, and ethylmethyldiethoxysilane. As silicon halide,
SiCl ₄ , SiHCl ₃ , SiH ₂ Cl _{2 and the} like can be mentioned.

When the second component element is a Group 15 element of the periodic table, halides and hydrates, ammonium salts, sulfates, organic acid salts and alkoxides of the Group 15 elements of the periodic table, especially It can be used without limitation.

As specific compounds, P ₂ O ₅ , PB
r ₃ , PCl ₃ , POBr ₃ , POCl ₃ , PO (OC
_{H 3) 3, PO (OC} 2 H 5) 3, PO (OC 3 H 7) 3, PO
(OC ₄ H ₉ ) ₃ , P (OCH ₃ ) ₃ , P (OC ₂ H ₅ ) ₃ , A
sBr ₃ , AsCl ₃ , AsI ₃ , As (OCH ₃ ) ₃ , A
s (OC ₂ H ₅ ) ₃ , As (OC ₃ H 7) ₃ , SbBr ₃ , S
bCl ₃ , SbCl ₅ , SbOCl, Sb ₂ (SO ₄ ) ₃ ,
Sb (OCH ₃ ) ₃ , Sb (OC ₂ H ₅ ) ₃ , Sb (OC ₃ H
₇ ) ₃ , Sb (OC ₄ H ₉ ) ₃ , BiBr ₃ , BiCl ₃ , B
iI ₃ , Bi (NO ₃ ) ₃ .xH ₂ O, BiOCl, Bi
(OC ₃ H ₇ ) _{3 and the} like.

When the second component element is a chalcogen element, halides and hydrates of the chalcogen element, ammonium salts, sulfates, organic acid salts, alkoxides and the like can be used without any particular limitation. it can.

As specific compounds, S ₂ Cl ₂ , SCl
₂ , SeO ₂ , SeO ₂ , SeBr ₄ , SeCl ₄ , Se
Examples include I ₄ , TeBr ₄ , TeCl ₄ , and TeO ₄ H ₂ .xH ₂ O.

The amount of the organic solvent-soluble compound to be added is not particularly limited as long as it is an amount necessary for optimizing the composition and fine structure of the obtained composite tin oxide powder and obtaining a high charge / discharge capacity. , S in the precursor solution
In terms of the atomic composition of n atoms and the second component element, an organic solvent-soluble compound is often added so that Sn atoms are in the range of 30.0 to 99.9 atomic%.

The method for dissolving the organic solvent-soluble compound in the organic solvent is not particularly limited. For example, a method in which an organic solvent is added dropwise to a tin compound, metal tin, and an organic solvent-soluble compound of the second component element under stirring, or a tin compound, metal tin, and an organic solvent-soluble compound of the second component element are added to the organic solvent while stirring. Can be used simultaneously or sequentially. In order to promote the dissolution of metal tin, it is also effective to reflux the organic solvent to dissolve the metal tin.

Further, for the purpose of controlling the pore diameter and the distribution of the obtained tin oxide powder, the precursor solution contains
A compound that is soluble in the organic solvent and has a higher boiling point than the organic solvent and that can be removed from the tin oxide powder by oxidization or the like during firing (hereinafter, also referred to as an organic solvent-soluble high-boiling compound) is added. May be. When a gel is prepared from a precursor solution containing an organic solvent-soluble high-boiling compound,
Organic solvent-soluble high-boiling compounds are uniformly dispersed in the gel. When such a gel is fired to produce tin oxide powder, the organic solvent-soluble high-boiling compound is eliminated during the firing process, and it becomes possible to introduce pores into the tin oxide powder. The average pore radius, pore volume, and distribution of the pores thus formed can be controlled by the properties of the organic solvent-soluble high-boiling compound to be added and the amount thereof. Preferred organic solvent-soluble high-boiling compounds differ depending on the organic solvent used. For example, when the organic solvent is methanol, the weight average molecular weight is 100 to 10,000.
It is preferable to add 0.1 to 50 parts by weight of polyethylene glycol of 0 to the organic solvent-soluble compound in the precursor solution.

Further, in order to accelerate the hydrolysis reaction, polymerization and condensation reaction of the organic solvent-soluble compound, some water may be added. The addition of water has effects such as sufficient progress of hydrolysis, polymerization and condensation reactions, particularly when preparing a precursor solution using an organic solvent-soluble compound such as an alkoxide. However, if the amount of water to be added is too large, precipitation occurs or gels rapidly,
There may be variations in the homogeneity of the composition and the like. The amount of water to be added is preferably 0.01 to 10 times as much as the molar amount of the organic solvent-soluble compound, though it varies depending on the kind of the organic solvent-soluble compound.

In the precursor solution thus obtained, the solute containing tin and the solute containing the second component element are uniformly mixed at the molecular level. Moreover, the solute containing tin and the solute containing the second component element are not dissolved separately as molecules or ions, but are polycondensed through a reaction with an organic solvent and the like, and dissolved as a sol. It is thought that there is. This is clear from the fact that the viscosity of the precursor solution gradually increases as the organic solvent is distilled off from the precursor solution, and finally, the precursor solution exhibits spinnability. Such polycondensation or sol formation of the solute was particularly remarkable when a halide or an alkoxide was used as a soluble tin or an organic solvent-soluble compound.

In the conventional solution method, since the solute containing tin and the solute containing the second component element in the aqueous solution do not particularly form a bond, the pH is adjusted to form a precipitate containing tin and the second component element. Even if it is attempted to form the precipitates, the precipitates containing tin and the precipitates containing the second component element are separated due to the different pHs at which the precipitates are formed. That is, the uniformity of mixing in a solution state could not be maintained until after precipitation.

On the other hand, in the precursor solution of the present invention,
It differs greatly from the aqueous solution used in the conventional solution method in that a polycondensate or a sol is formed after tin and the second component element are uniformly mixed. Therefore, when the precursor solution of the present invention is gelled, tin and the second component element are uniformly mixed at the molecular level without particular consideration for maintaining uniformity of mixing in the solution state. The resulting gel can be formed using widely known methods.

The method for forming the gel depends on the type of the tin compound and the organic solvent-soluble compound used for preparing the precursor solution. However, the method for concentrating and drying the precursor solution, the method for forming the precursor solution and the aqueous alkaline solution, May be mixed to form a gel, or a method may be used in which a compound that releases ammonia or an aqueous solution thereof is added to a precursor solution, and ammonia is released from the compound to form a gel.

When a gel is formed by concentrating and drying the precursor solution, the precursor solution is heated,
A gel can be formed by removing volatile components such as an organic solvent in the precursor solution using a rotary evaporator or the like.

When a gel is formed by mixing a precursor solution and an alkaline aqueous solution, an alkaline aqueous solution is added to the precursor solution, or conversely, a precursor solution is added to the alkaline aqueous solution to form a gel. The pH can be adjusted to form a gel as a precipitate. At this time, as described above, in the precursor solution of the present invention, the solute containing tin and the solute containing the second component element are polycondensed to form a sol. Separation of the composition as in the conventional solution method does not occur, and a uniform mixed state at the molecular level is maintained even in the gel.
The alkaline aqueous solution used for gel formation is not particularly limited, but ammonia water, an aqueous sodium hydroxide solution, or the like can be used. If sodium hydroxide is used as the alkaline aqueous solution, sodium remains in the tin oxide powder and the charge / discharge capacity may be reduced. Therefore, a particularly preferred alkaline aqueous solution is ammonia water. The concentration or amount of the alkaline aqueous solution may be determined according to the acidity of the precursor solution.

A gel can also be formed by adding a compound that releases ammonia or an aqueous solution thereof to the precursor solution and releasing ammonia from the compound. Examples of the compound capable of releasing ammonia include compounds such as urea, hexamethylenetetramine, formamide, and acetamide. Since these compounds release ammonia by heating, when the precursor solution to which these compounds or the aqueous solution is added is heated, the pH of the precursor solution is adjusted by the released ammonia, and a gel is formed as a precipitate. The heating temperature for releasing ammonia varies depending on the type of the compound used, but ammonia can be released by heating to 60 ° C. or higher. Further, the amounts of these compounds to be added may be determined according to the acidity of the precursor solution. The method of releasing ammonia in the precursor solution may be effective in controlling the shape of the gel because gelation occurs more uniformly than in the case where the precursor solution and the alkaline aqueous solution are mixed.

The gel thus obtained is in a form such as bulk or powder. The composite tin oxide powder of the present invention can be obtained by baking in this state, but for the purpose of adjusting the particle size of the composite tin oxide powder, a bulk or powder gel is crushed or ground by a known method. Granulation is also preferred.

By firing the gel thus obtained, a tin oxide powder can be obtained. In the gel prepared in the present invention, tin and the second component element are uniformly mixed at the molecular level, so that if calcination is performed at a temperature of about 250 ° C. or higher, a composite tin oxide powder having a uniform composition can be obtained. Can be. As described above, the fine structure of the tin oxide powder changes greatly depending on the firing temperature. In the conventional method, 100
Since firing at a temperature close to 0 ° C. was necessary for homogenizing the composition, a composite tin oxide powder having a fine structure that could only be obtained at a temperature lower than that was not able to be produced. Therefore, conventionally, there was little room for optimizing the fine structure of the composite tin oxide powder in order to improve the charge / discharge capacity and cycle characteristics. In contrast, in the present invention, 250
If baked at a temperature of not less than ° C., a composite tin oxide powder having a uniform composition can be obtained, so that a composite tin oxide powder having a fine structure that cannot be obtained by a conventional production method can be produced. Therefore, the use of the manufacturing method of the present invention makes it possible to optimize the fine structure of the composite tin oxide powder by firing conditions and the like in order to improve characteristics such as charge / discharge capacity and cycle characteristics.

The firing temperature for firing the gel is from 250 to
Preferably it is 1200 ° C. If the firing temperature is extremely higher or lower than this, the charging / discharging capacity of the obtained tin oxide powder may decrease, which is not preferable. Therefore, a more preferable firing temperature is 500 to 1100.
° C.

The firing time varies depending on the firing temperature, atmosphere, and the like, but the firing time is preferably 0.03 to 8 hours. The heating rate during firing is not particularly limited,
Preferably it is 0.1 to 100 ° C / min.

The atmosphere during firing is not particularly limited. For example, an atmosphere filled with an oxidizing gas such as air, oxygen, water vapor, or a mixed gas thereof, or an inert gas such as helium, neon, or argon, nitrogen, or a reducing gas such as hydrogen or carbon monoxide. Atmosphere and the like. However, in the case of an atmosphere of an inert gas or a reducing gas, there is a case where a large amount of metal tin is generated by being reduced in addition to tin oxide, or a large amount of organic matter remains and cycle characteristics are deteriorated. The atmosphere is an oxidizing gas atmosphere, and among them, an atmosphere containing oxygen is particularly preferable. Also, in order to improve cycle characteristics, once tin oxide is produced in an oxidizing gas atmosphere, the average valence of tin is adjusted in a reducing atmosphere to a range of more than 0 to 4 or less. Firing in an oxidizing gas atmosphere and firing in a reducing gas atmosphere can be combined.

The structure of the tin oxide powder produced according to the present invention may be either crystalline tin oxide or amorphous tin oxide depending on the firing conditions and the second component element.

When the tin oxide powder of the present invention is crystalline, its crystal structure is the same as the crystal structure of tin dioxide J.
Tetragonal tin dioxide described in CPDS card 21-1250,
29-13484, orthorhombic tin dioxide, 33-13
74, a cubic tin dioxide or the like. In some cases, the crystal structure of ditin trioxide having the crystal structure described in JCPDS card 25-1259 is adopted. In some cases, a crystal structure of tritin tetroxide having a crystal structure described in JCPDS card 20-1293 is used.
Also, a JCPDS card 6 having a crystal structure of tin monoxide is used.
In some cases, the compound may have a crystal structure such as tetragonal tin monoxide described in -395, tin monoxide having the crystal structure described in 7-195, or orthorhombic tin monoxide described in 24-1342. Further, two or more types of tin oxide having the above-mentioned crystal structure may be contained in an arbitrary ratio.

The crystal structure of the tin oxide powder can be determined based on the position and intensity of the diffraction peak obtained by powder X-ray diffraction, electron diffraction, or the like. The position and intensity of the diffraction peak of powder X-ray diffraction may show slight fluctuation due to solid solution of elements other than tin and oxygen, crystal orientation, etc., but are registered in the above-mentioned JCPDS card and the like. The crystal structure of the tin oxide powder can be determined by comparing the intensity of the diffraction peak with the intensity of the tin oxide.

The composition of the tin oxide powder produced according to the present invention varies depending on the type and amount of the added organic solvent-soluble compound, but the second component element is uniformly dispersed in the tin oxide. Often in one phase. However, there may be a structure having a (A) phase composed of tin oxide having a crystallite size of 1 to 30 nm and a (B) phase composed of an oxide of a second component element such as silicon oxide. Specifically, a structure in which the (A) phase having a maximum diameter of 1 μm or less is precipitated using the (B) phase as a mother phase, or a structure in which a (B) phase having a maximum diameter of 1 μm or less is precipitated using the (A) phase as a mother phase. May take. However, even when such phase separation occurs, the phase separation is uniform throughout the powder, and is substantially different from non-uniform composition such as segregation generated in tin oxide powder produced by the solid-state reaction method. Things. The fine structure due to the phase separation can be observed with a transmission electron microscope or the like, and the size can be measured by small angle X-ray scattering or the like. Further, the composition of the composite tin oxide powder of the present invention usually maintains the charged composition of the organic solvent-soluble compound. The types and contents of the elements contained in the tin oxide powder can be identified and quantified by chemical analysis, fluorescent X-ray analysis, or the like.

In the production method of the present invention, tin oxide powder having an average particle diameter in the range of 0.01 to 100 μm is obtained, depending on conditions and the like. The average particle diameter _Ra is the maximum width (major axis: L) and the maximum width (minor axis: B) of the n (n> 30) particles in the direction perpendicular to the major axis for the particles constituting the tin oxide powder. It can be measured and determined by the following equation 1.

[0069]

[0070]

Specific surface area measured by the BET method of the tin oxide powders produced by Equation 1] The present invention varies depending on the production conditions such as the firing conditions and the second component element, 0.5～300M ² /
g.

The pore structure of a typical tin oxide powder produced according to the present invention has an average pore radius of 0.05 to 25 n.
m in the range of 0.01 to 1.0 cm ³ /
g, and the volume of such pores is 1% of the total pore volume.
Often accounts for more than 5%. These average pore radii,
The pore volume can be measured by a mercury intrusion method, a gas adsorption method, an X-ray small angle scattering method, a high pressure electron microscope, or the like.

When the tin oxide powder produced by the production method of the present invention is crystalline, the typical crystallite size is 1 to 300 nm. The crystallite size can be determined by the Scherrer method from the spread of the diffraction peaks observed by powder X-ray diffraction and the like (Karity, translated by Gentaro Matsumura, "New Edition X-ray Diffraction Guideline, 9"
1 page Agne, 1985). It can also be confirmed by direct observation with a transmission electron microscope or the like.

Although tin oxide powder having a fine structure such as specific surface area, pore structure and crystallite diameter as described above and having a uniform composition has been very difficult to produce by the conventional production method,
According to the present invention, the tin oxide powder as described above can be manufactured. In addition, the tin oxide powder having the optimized fine structure can significantly improve the charge / discharge capacity. For example, according to the present invention, it contains 10 mol% of silicon oxide and 5 mol% of antimony oxide, has a specific surface area of 86.3 m ² / g, and has an average pore radius of 0.0
The pore volume in the range of 5 to 25 nm is 0.17 cm ³
/ G, and the volume of such pores accounts for 82% of the total pore volume, and a tin oxide powder having a crystallite size of 2.6 nm can be produced. The charge / discharge capacity of the tin oxide powder is 763 mAh / g. On the other hand, the charge / discharge capacity of tin oxide powder having the same charged composition produced by the solid-state reaction method is remarkably low at 325 mA / g.

The tin oxide powder produced by the present invention can be used as it is as a non-aqueous electrolyte secondary battery non-polar active material, but the difference between the initial charge capacity and discharge capacity (also referred to as irreversible capacity). In order to reduce the size, lithium can be previously stored in the tin oxide. As a method for producing the tin oxide powder, a method of adding a lithium compound corresponding to the irreversible capacity at the same time to form the compound in the tin oxide powder, or an organic electrolytic solution in which a lithium salt is dissolved is used. A method in which lithium is electrochemically occluded in the tin oxide powder using lithium metal or a lithium alloy as a counter electrode in the liquid can be employed.

It is also possible to modify the surface of tin oxide to reduce the irreversible capacity. For example, only the tin oxide surface can be changed to SnO, or carbon coating can be performed. Further, if only the surface layer is changed to Sn, the irreversible capacity may be effectively reduced.

When the tin oxide powder produced as described above is used as a negative electrode active material for a non-aqueous electrolyte secondary battery, the structure and production of the non-aqueous electrolyte secondary battery should be performed by a known method. Can be. A typical manufacturing method is described below.

First, a tin oxide powder and / or a composite tin oxide powder are 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 wound in a cylindrical shape in the case of a cylindrical non-aqueous electrolyte secondary battery, and folded in the case of a square non-aqueous electrolyte secondary battery. The electrode portion is manufactured by overlapping. 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 , or polyaniline, polyacetylene, polyparaphenylene, polyphenylenevinylene, polypyrrole,
A material capable of inserting and extracting lithium, such as a conjugated polymer such as polythiophene or a crosslinked polymer having a disulfide bond, may be used.

As the current collector, a band-shaped thin plate or mesh made of copper, aluminum, or the like may 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 as 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.

[0084]

According to the present invention, a tin oxide powder having a controlled fine structure can be produced by dissolving an organic solvent-soluble compound of tin and the second component element in an organic solvent, gelling and firing. The tin oxide powder produced by the present invention has, for example, a large specific surface area of 10 to 150 m ² / g,
The volume of pores having an average pore radius of 5 to 25 nm is 0.
1 to 0.5 cm ³ / g, the volume of such pores occupies 70% or more of the whole, and the crystallite size is 1 to 3
A fine structure having a thickness of 0 nm can be obtained.

When the tin oxide powder was used as a negative electrode active material of a non-aqueous electrolyte secondary battery, the charge / discharge capacity was particularly large, so that the battery performance could be greatly improved.

[0086]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

The measurement of the discharge capacity of tin oxide shown in the following Examples and Comparative Examples was performed as follows.

Tin oxide, polyvinylidene fluoride (binder)
And acetylene black (conductivity imparting agent) at 80/5
/ 15 (weight ratio).
To 1 g, 1 ml of N-methylpyrrolidone was added and kneaded to prepare a paste. This paste was dried in a vacuum dryer at 100 ° C. for 24 hours. Dry paste 6m
g was applied to a nickel mesh to form a negative electrode. As the non-aqueous electrolyte, a solution prepared by dissolving LiClO ₄ (at a concentration of 1 mol / liter) in a mixed solvent of ethylene carbonate and diethyl carbonate in an equal volume was used. A glass container is used for the battery container, and two positive electrodes (using lithium) are placed on both sides of one negative electrode, and one reference electrode (using lithium) is arranged near the negative electrode. A simple battery cell was constructed by suspending from the lid with a nickel wire with a clip (covered with a glass tube).

Using a charge / discharge device (manufactured by Hokuto Denko), a charge / discharge cycle test of the above simple battery cell was performed, and the charge / discharge capacity of the negative electrode active material was measured. In the charge / discharge cycle test,
The test was performed at a current value (constant) corresponding to 30 mA / g. The discharge capacity of the negative electrode active material was calculated from the capacity = 30 × t (unit; mAh / g) by measuring the discharge time t (unit: time). The charge / discharge is 0 to the reference electrode.
The test was performed within a range of 1.99V. Note that the discharge capacities shown in Examples and Comparative Examples indicate the discharge capacities at the time of the first discharge.

Example 1 9.48 g (0.05 mol) of stannous chloride (SnCl ₂ ), 5.94 g (0.05 mol) of tin metal, and tetraethoxy in 64.2 g (2.0 mol) of methanol 2.30 g (0.011 mol) of silane (Si (0C ₂ H ₅ ) ₄ )
And 1.21 g of antimony trichloride (SbCl ₃ )
(0.0053 mol) was sequentially dissolved under reflux to prepare a uniform and transparent precursor solution. The gel obtained by concentrating the precursor solution was heated at 280 ° C. in air using an electric furnace.
For 1 hour to obtain a tin oxide powder.

As a result of powder X-ray diffraction, the obtained tin oxide powder was amorphous. Further, since no diffraction X-ray peak due to antimony oxide or silicon oxide was detected, it was found that the second component element, antimony and silicon, did not segregate and was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to silicon and the ratio of tin to antimony in the tin oxide powder were almost the same as the charging ratio.

The specific surface area of the tin oxide powder determined by the BET method was 94.2 m ² / g. When the pore structure of the obtained tin oxide powder was analyzed by mercury intrusion method,
The volume of pores having an average pore size of 0.05-25 nm is 0.23 cm ³ / g, which is 68% of the total pore volume
Met.

Using the tin oxide powder, the simplified battery cell was prepared and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 702 mAh / g.

Example 2 A gel prepared in the same manner as in Example 1 was fired in an electric furnace at 600 ° C. for 1 hour in air to obtain a tin oxide powder.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to antimony oxide or silicon oxide was detected, it was found that the second component element, antimony and silicon, did not segregate and was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to silicon and the ratio of tin to antimony in the tin oxide powder were almost the same as the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 2.8 nm.
And also agreed with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 45.3 m ² / g. When the pore structure of the obtained tin oxide powder was analyzed by mercury intrusion method,
The volume of pores having an average pore diameter of 0.05 to 25 nm is 0.12 cm ³ / g, which is 70% of the total pore volume
Met.

Using the tin oxide powder, the simplified battery cell was prepared and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 747 mAh / g.

Example 3 A gel prepared in the same manner as in Example 1 was fired in an electric furnace at 700 ° C. for 1 hour in air to obtain a tin oxide powder.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to antimony oxide or silicon oxide was detected, it was found that the second component element, antimony and silicon, did not segregate and was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to silicon and the ratio of tin to antimony in the tin oxide powder were almost the same as the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 3.0 nm.
And also agreed with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 43.8 m ² / g. When the pore structure of the obtained tin oxide powder was analyzed by mercury intrusion method,
The volume of the pores having an average pore diameter of 0.05-25 nm is 0.09 cm ³ / g, which is 67% of the total pore volume
Met.

Using the tin oxide powder, the simplified battery cell was manufactured and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 752 mAh / g.

Example 4 A gel prepared in the same manner as in Example 1 was fired at 1,000 ° C. for 1 hour in air using an electric furnace to obtain tin oxide powder.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to antimony oxide or silicon oxide was detected, it was found that the second component element, antimony and silicon, did not segregate and was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to silicon and the ratio of tin to antimony in the tin oxide powder were almost the same as the charging ratio.

The crystallite size of this tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 15.0 n.
m, which was also consistent with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 20.6 m ² / g. When the pore structure of the obtained tin oxide powder was analyzed by mercury intrusion method,
The volume of the pores having an average pore size of 0.05-25 nm is 0.07 cm ³ / g, which is 63% of the total pore volume
Met.

Using the tin oxide powder, the simplified battery cell was manufactured and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 710 mAh / g.

Example 5 9.48 g (0.05 mol) of stannous chloride (SnCl ₂ ), 5.94 g (0.05 mol) of metal tin, and 64.2 g (2.0 mol) of methanol 1.05 g (0.011 mol) of magnesium (MgCl ₂ ) was sequentially dissolved under reflux to prepare a uniform and transparent precursor solution. The gel obtained by concentrating the precursor solution was baked at 600 ° C. for 1 hour in the air using an electric furnace to obtain tin oxide powder.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to magnesium oxide was detected, it was found that magnesium oxide was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to magnesium in the tin oxide powder was almost equal to the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 4.8 nm.
And also agreed with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 31.3 m ² / g.

Using the above fired product, the above-mentioned simplified battery cell was manufactured and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 698 mAh / g.

Example 6 1.05 g (0.01 g) of magnesium chloride (MgCl ₂ )
1 mol) instead of titanium chloride (TiCl ₄ ) 2.09
g (0.011 mol), except that tin oxide powder was obtained in the same manner as in Example 5.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to titanium oxide was detected, it was found that titanium oxide was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to titanium in the tin oxide powder was almost equal to the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 16.4 n.
m, which was also consistent with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 18.2 m ² / g.

Using the above fired product, the above-described simplified battery cell was fabricated and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 705 mAh / g.

Example 7 1.05 g (0.01 g) of magnesium chloride (MgCl ₂ )
1 mol) instead of vanadium chloride (VCl ₄ ) 1.0
Example 5 except that 2 g (0.0053 mol) was used.
In the same manner as described above, a tin oxide powder was obtained.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to vanadium oxide was detected, it was found that vanadium oxide was uniformly dissolved in tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin and vanadium in the tin oxide powder is
It almost coincided with the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 15.3 n.
m, which was also consistent with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 14.9 m ² / g.

Using the above fired product, the above-mentioned simplified battery cell was manufactured and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 710 mAh / g.

Example 8 1.05 g (0.01 g) of magnesium chloride (MgCl ₂ )
Instead of niobium chloride 1 mole) (NbCl ₅₎ 1.43
A tin oxide powder was obtained in the same manner as in Example 5 except that g (0.0053 mol) was used.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to niobium oxide was detected, it was found that niobium oxide was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to niobium in the tin oxide powder was almost equal to the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 17.7 n.
m, which was also consistent with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 15.6 m ² / g.

Using the above fired product, the above-described simplified battery cell was fabricated and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 708 mAh / g.

Example 9 Magnesium chloride (MgCl ₂ ) 1.05 g (0.01
(1 mol) instead of cerium chloride (CeCl ₃ ) 2.7
Example 5 except that 1 g (0.0011 mol) was used.
In the same manner as described above, a tin oxide powder was obtained.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Since no diffraction X-ray peak due to cerium oxide was detected, it was found that cerium oxide was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to cerium in the tin oxide powder was almost equal to the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 17.7 n.
m, which was also consistent with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 15.6 m ² / g.

Using the above fired product, the above-mentioned simplified battery cell was prepared and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 708 mAh / g.

Example 10 Magnesium chloride (MgCl ₂ ) 1.05 g (0.01
1 mol) instead of aluminum chloride (AlCl ₃ )
A tin oxide powder was obtained in the same manner as in Example 5, except that 1.47 g (0.011 mol) was used.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to aluminum oxide was detected, it was found that aluminum oxide was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to aluminum in the tin oxide powder was almost equal to the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 10.4 n
m, which was also consistent with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 20.0 m ² / g.

Using the above fired product, the above-mentioned simplified battery cell was fabricated and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 705 mAh / g.

Example 11 Magnesium chloride (MgCl ₂ ) 1.05 g (0.01
1 mol) instead of trimethoxyboron (B (OC
H _{3) 3)} 2.71g (0.021 mol) and triethoxysilane phosphoryl _{(PO (OEt) 3) 3.83g} (0.
021 mol) in the same manner as in Example 5 to obtain a tin oxide powder.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to boron oxide or phosphorus oxide was detected, it was found that boron oxide and phosphorus oxide were uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to boron and the ratio of tin to phosphorus in the tin oxide powder were almost the same as the charged ratios.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 2.1 nm.
And also agreed with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 32.7 m ² / g.

Using the fired product, the simplified battery cell was fabricated and subjected to a charge / discharge cycle test. The discharge capacity was 725 mAh / g.

Example 12 1.05 g (0.01 g of magnesium chloride (MgCl ₂ ))
1 mol) instead of trimethoxyboron (B (OC
H ₃ ) ₃ ) 2.71 g (0.021 mol), triethoxyphosphoryl (PO (OEt) ₃ ) 3.83 g (0.02 mol)
1 mol) and antimony trichloride (SbCl ₃ ) 1.2
Example 5 except that 1 g (0.0053 mol) was used.
In the same manner as described above, a tin oxide powder was obtained.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to boron oxide, phosphorus oxide or antimony oxide was detected, it was found that boron oxide, phosphorus oxide and antimony oxide were uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin and boron, the ratio of tin and phosphorus, and the ratio of tin and antimony in the tin oxide powder were almost equal to the charged ratios.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 2.5 nm.
And also agreed with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 33.3 m ² / g.

The simplified battery cell was prepared using the above fired product, and a charge / discharge cycle test was performed. As a result, the discharge capacity was 730 mAh / g.

Example 13 Magnesium chloride (MgCl ₂ ) 1.05 g (0.01
1 mole) instead of tetraethoxysilane (Si (0C
₂ H _{5) 4)} except using 8.98 g (0.043 mol) was obtained tin oxide powder in the same manner as in Example 5.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Since no diffraction X-ray peak due to silicon oxide was detected, it was found that silicon oxide was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis,
The ratio of tin to silicon in the tin oxide powder was almost equal to the charge ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 1.9 nm.
And also agreed with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 38.4 m ² / g.

Using the above fired product, the above-mentioned simplified battery cell was fabricated and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 728 mAh / g.

Example 14 1.05 g (0.01 g of magnesium chloride (MgCl ₂ ))
1 mol) instead of antimony chloride (SbCl ₃ ).
A tin oxide powder was obtained in the same manner as in Example 5 except that 21 g (0.0053 mol) was used.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to antimony oxide was detected, it was found that antimony oxide was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to antimony in the tin oxide powder is
It almost coincided with the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 17.3 n.
m, which was also consistent with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 13.8 m ² / g.

Using the above fired product, the above-mentioned simplified battery cell was fabricated and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 703 mAh / g.

Example 15 Magnesium chloride (MgCl ₂ ) 1.05 g (0.01
1 mol) instead of selenium chloride (SeCl ₄ ) 2.43
g (0.011 mol), except that tin oxide powder was obtained in the same manner as in Example 5.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to selenium was detected, it was found that selenium was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to selenium in the tin oxide powder was almost equal to the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 6.2 nm.
And also agreed with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 26.5 m ² / g.

Using the above fired product, the above-mentioned simplified battery cell was manufactured and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 695 mAh / g.

Example 16 9.48 g (0.05 mol) of stannous chloride (SnCl ₂ )
A tin oxide powder was obtained in the same manner as in Example 2, except that 18.96 g (0.10 mol) of stannous chloride (SnCl ₂ ) was used instead of 5.94 g (0.05 mol) of metal tin. .

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. In addition, since no diffraction X-ray peak due to antimony oxide or silicon oxide was detected, it was found that there was no segregation of the second component element, antimony and silicon, and that the second component element was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to silicon and the ratio of tin to antimony in the tin oxide powder were almost the same as the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 2.7 nm.
And also agreed with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 45.1 m ² / g.

Using the tin oxide powder, the simplified battery cell was manufactured and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 750 mAh / g.

Example 17 9.48 g (0.05 mol) of stannous chloride (SnCl ₂ )
And stannous chloride dihydrate (SnCl ₂ .2H ₂ O) 22.56 g instead of 5.94 g (0.05 mol) of metal tin
(0.10 mol), except that tin oxide powder was obtained in the same manner as in Example 2.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to antimony oxide or silicon oxide was detected, it was found that the second component element, antimony and silicon, did not segregate and was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to silicon and the ratio of tin to antimony in the tin oxide powder were almost the same as the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 3.5 nm.
And also agreed with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 46.3 m ² / g.

Using the tin oxide powder, the simplified battery cell was manufactured and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 748 mAh / g.

Example 18 A tin oxide powder was obtained in the same manner as in Example 2 except that 92.0 g (2.0 mol) of ethanol was used instead of 64.2 g (2.0 mol) of methanol.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to antimony oxide or silicon oxide was detected, it was found that the second component element, antimony and silicon, did not segregate and was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to silicon and the ratio of tin to antimony in the tin oxide powder were almost the same as the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 5.3 nm.
And also agreed with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 38.7 m ² / g.

Using the tin oxide powder, the simplified battery cell was prepared and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 740 mAh / g.

Example 19 Into 64.2 g (2.0 mol) of methanol, 9.48 g (0.05 mol) of stannous chloride (SnCl ₂ ), 5.94 g (0.05 mol) of metal tin, and tetraethoxy 2.30 g (0.011 mol) of silane (Si (0C ₂ H ₅ ) ₄ )
And 1.21 g of antimony trichloride (SbCl ₃ )
(0.0053 mol) was sequentially dissolved under reflux to prepare a uniform and transparent precursor solution. Add 2 to this precursor solution
A gel was obtained by adding 37.5 g of 8% aqueous ammonia. This gel was separated by filtration and dried, and then calcined at 600 ° C. for 1 hour in the air using an electric furnace to obtain a tin oxide powder.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to antimony oxide or silicon oxide was detected, it was found that the second component element, antimony and silicon, did not segregate and was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to silicon and the ratio of tin to antimony in the tin oxide powder were almost the same as the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 6.1 nm.
And also agreed with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 42.5 m ² / g.

Using the tin oxide powder, the simplified battery cell was prepared and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 745 mAh / g.

Example 20 To 64.2 g (2.0 mol) of methanol was added 9.4 g (0.05 mol) of stannous chloride (SnCl ₂ ), 5.94 g (0.05 mol) of metallic tin, 2.30 g (0.011 mol) of tetraethoxysilane (Si (0C ₂ H ₅ ) ₄ )
And 1.21 g of antimony trichloride (SbCl ₃ )
(0.0053 mol) was sequentially dissolved under reflux to prepare a uniform and transparent precursor solution. In this precursor solution,
A urea aqueous solution in which 18 g of urea was dissolved in 25 g of water was added, and the mixture was heated at 60 ° C. for 12 hours with stirring to obtain a gel. This gel was separated by filtration and dried, and then calcined at 600 ° C. for 1 hour in the air using an electric furnace to obtain a tin oxide powder.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Further, since no diffraction X-ray peak due to antimony oxide or silicon oxide was detected, it was found that the second component element, antimony and silicon, did not segregate and was uniformly dissolved in the tin oxide powder. According to the fluorescent X-ray analysis, the ratio of tin to silicon and the ratio of tin to antimony in the tin oxide powder were almost the same as the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 5.7 nm.
And also agreed with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 42.5 m ² / g.

Using the tin oxide powder, the simplified battery cell was fabricated and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 738 mAh / g.

Example 21 To 64.2 g (2.0 mol) of methanol, 9.48 g (0.05 mol) of stannous chloride (SnCl ₂ ), 5.94 g (0.05 mol) of metal tin, and tetraethoxy 2.30 g (0.011 mol) of silane (Si (0C ₂ H ₅ ) ₄ )
And 1.21 g of antimony trichloride (SbCl ₃ )
(0.0053 mol) was sequentially dissolved under reflux to prepare a uniform and transparent precursor solution. The precursor solution was concentrated, and the viscous precursor solution was spun to obtain a fiber diameter of 5%.
A gel fiber of 0 μm was obtained. After the gel fibers were pulverized in a mortar, they were fired in an air at 280 ° C. for 1 hour using an electric furnace to obtain tin oxide powder having an average particle diameter of 40 μm.

As a result of powder X-ray diffraction, the obtained tin oxide powder was crystalline tin oxide having a rutile structure. Since no diffraction X-ray peak due to antimony oxide or silicon oxide was detected, it was found that the second component element, antimony and silicon, did not segregate and was uniformly dissolved in the tin oxide powder. . According to the fluorescent X-ray analysis, the ratio of tin to silicon and the ratio of tin to antimony in the tin oxide powder were almost the same as the charging ratio.

The crystallite size of the tin oxide powder determined from the diffraction X-ray peak from the (211) plane was 6.3 nm.
And also agreed with the observation result by the transmission electron microscope.

The specific surface area of the tin oxide powder determined by the BET method was 39.8 m ² / g.

Using the tin oxide powder, the simplified battery cell was manufactured and subjected to a charge / discharge cycle test. As a result, the discharge capacity was 740 mAh / g.

Comparative Example 1 12.1 g (0.08 g) of commercially available tin dioxide (SnO ₂ ) powder
Mol), 2.04 g of silicon dioxide (SiO ₂ ) powder (0.
034 mol) and antimony oxide (Sb ₂ O ₃₎ were mixed for 8 hours powder 1.22g of (0.0042 mol) in rotation ball mill. This mixed powder is placed in air at 600 ° C. for 1 hour.
Fired for hours. As a result of performing powder X-ray diffraction of the obtained fired product, diffraction X-ray peaks of SnO ₂ , SiO ₂ and Sb ₂ O ₃ were detected. When the structure was observed with a scanning electron microscope, it was found that silicon oxide and tin oxide in the fired product were each present as large particles, and the composition was not uniform.

The above-described fired product was used to fabricate the simplified battery cell, and a charge / discharge cycle test was performed. As a result, the discharge capacity was 325 mAh / g, which was lower than the tin oxide-based negative electrode active material of the present invention. Was.

Comparative Example 2 12.1 g (0.08 g) of commercially available tin dioxide (SnO ₂ ) powder
Mol), 2.04 g of silicon dioxide (SiO ₂ ) powder (0.
034 mol) and antimony oxide (Sb ₂ O ₃₎ were mixed for 8 hours powder 1.22g of (0.0042 mol) in rotation ball mill. This mixed powder was fired in air at 1000 ° C. for 12 hours. As a result of powder X-ray diffraction of the obtained fired product, a diffraction X-ray peak of SiO ₂ was detected in addition to a diffraction X-ray peak of SnO ₂ .

The specific surface area of the calcined product determined by the BET method was 9.8 m ² / g, which was lower than that of the tin oxide powder of the present invention.

The above-described simplified battery cell was prepared using the fired product, and subjected to a charge / discharge cycle test. The discharge capacity was 375 mAh / g, which was also lower than the tin oxide-based negative electrode active material of the present invention. Was.

Comparative Example 3 Tin tetrachloride (SnCl ₄ ) 26.5 g (0.
10 mol), tetraethoxysilane (Si (OC ₂ H ₅ )
₄ ) 2.30 g (0.011 mol) and 1.21 g (0.0053 mol) of antimony trichloride (SbCl ₃ ) were dissolved, and a precipitate was formed by adding 37.5 g of 28% aqueous ammonia to this solution. Was. After the precipitate was separated by filtration and dried, it was baked at 600 ° C. for 1 hour in the air using an electric furnace. As a result of powder X-ray diffraction of the obtained fired product, a diffraction X-ray peak of SiO ₂ was detected in addition to a diffraction X-ray peak of SnO ₂ . When the structure was observed with a scanning electron microscope, segregation of silicon oxide was confirmed in the fired product, and the composition was found to be non-uniform.

The above-described fired product was used to fabricate the simplified battery cell, and a charge / discharge cycle test was performed. As a result, the discharge capacity was 320 mAh / g, which was lower than the tin oxide-based negative electrode active material of the present invention. Was.

Comparative Example 4 Tin tetrachloride (SnCl ₄ ) 26.5 g (0.
10 mol), tetraethoxysilane (Si (OC ₂ H ₅ )
₄ ) 2.30 g (0.011 mol) and 1.21 g (0.0053 mol) of antimony trichloride (SbCl ₃ ) were dissolved, and a precipitate was formed by adding 37.5 g of 28% aqueous ammonia to this solution. Was. After the precipitate was separated by filtration and dried, the precipitate was calcined in air at 1000 ° C. for 12 hours using an electric furnace. As a result of powder X-ray diffraction of the obtained fired product, a diffraction X-ray peak of SnO ₂ was detected. When the structure was observed with a scanning electron microscope, no segregation of silicon oxide was found in the fired product.

The specific surface area of the fired product determined by the BET method was 7.8 m ² / g, which was lower than that of the tin oxide powder of the present invention.

The above-described fired product was used to fabricate the simplified battery cell, and a charge-discharge cycle test was conducted. The discharge capacity was 369 mAh / g, which was also lower than the tin oxide-based negative electrode active material of the present invention. Was.

Claims (3)

[Claims] An organic solvent-soluble tin compound and / or metallic tin, an organic solvent-soluble alkaline earth metal compound, an organic solvent-soluble rare earth element compound, an organic solvent-soluble transition element compound, and an organic solvent-soluble periodic table group 13 element compound ,
At least one soluble compound selected from the group consisting of organic solvent-soluble periodic table group 14 element compounds (excluding organic solvent-soluble tin compounds), organic solvent-soluble periodic table group 15 element compounds, and organic solvent-soluble chalcogen element compounds; A method for producing a tin oxide powder, comprising dissolving in an organic solvent to form a precursor solution, forming a gel from the precursor solution, and then firing the gel. 2. A negative electrode active material for a non-aqueous secondary battery, comprising a tin oxide powder obtained by the production method according to claim 1. 3. A negative electrode obtained by bonding the negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 2 to a current collector, and a positive electrode active material comprising a material capable of inserting and extracting lithium ions. A non-aqueous electrolyte secondary battery characterized in that a positive electrode formed by bonding a positive electrode to a current collector is housed in a battery container together with a non-aqueous electrolyte through a separator.