JPH1092425A - Method for producing negative electrode active material for tin oxide based non-aqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a high-capacity negative electrode active material for a tin oxide-based non-aqueous electrolyte secondary battery in a high yield and with good reproducibility, and furthermore, sintering in a short time within 10 hours. It is an object of the present invention to provide a manufacturing method which can be performed. SOLUTION: Alcohols such as methanol, ethanol and the like, alcohol-soluble tin compounds such as stannous chloride and stannous bromide, metallic tin, tantalum pentachloride, alcohol-soluble periodic table group 5 element compounds such as niobium pentachloride, Alcohol-soluble Group 15 element compounds such as antimony trichloride, tetraethoxysilane, aluminum chloride, tetraethoxygermanium, tetrabutoxytitanium, tetrabutoxyzirconium, magnesium chloride,
After preparing a precursor solution by dissolving an alcohol-soluble metal compound such as trimethoxyboron, ethyl cellulose, an alcohol-soluble polymer compound such as polyethylene oxide, etc., concentrating, and then calcining, a tin oxide non-aqueous solution A method for producing a negative electrode active material for an electrolyte secondary battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a negative electrode active material for a non-aqueous electrolyte secondary battery and a method for producing the same.

[0002]

2. Description of the Related Art As a power source for portable equipment such as a cellular phone and a portable terminal which are rapidly spreading today, a small and lightweight power source is used.
There is a demand for a battery that can be operated for a long time.
There are two types of batteries, primary batteries such as dry batteries that cannot be charged, and secondary batteries that can be used repeatedly by charging.Depending on the type of portable device and the circumstances in which those devices are used,
Each battery is used properly.

[0003] Among secondary batteries, a non-aqueous electrolyte secondary battery (also referred to as a non-aqueous secondary battery) uses a non-aqueous solvent for the electrolyte, and thus can obtain a high battery voltage exceeding the decomposition voltage of water. Therefore, as compared with other secondary batteries such as a lead storage battery, a nickel-cadmium battery, and a nickel-hydrogen battery, the non-aqueous electrolyte secondary battery has a high battery capacity and a high energy density, so that the size and size of the battery can be reduced. Light weight is possible, and the demand for power supply for portable equipment is rapidly growing. However, there is a demand for a secondary battery that allows portable equipment and the like to operate for a longer time.

[0004] Non-aqueous electrolyte secondary batteries include Ti, Mo, N
Capable of absorbing and releasing lithium such as oxides, sulfides, selenides, or conductive polymers such as polyaniline and polyacene of metals and lithium such as b, Cr, Mn, V, Ni, and Co A positive electrode composed of a positive electrode active material 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 such as LiClO ₄ or LiPF ₆ in propylene carbonate. And ethylene carbonate, a non-aqueous electrolyte dissolved in a non-aqueous solvent such as 1,2-dimethoxyethane,
And a separator, a battery container, and the like.

[0005] In a non-aqueous electrolyte secondary battery, lithium moves between the positive electrode and the negative electrode in an ion state as the battery is charged and discharged, and at the same time, electrons are transferred from the non-aqueous electrolyte secondary battery to a charger or portable equipment. It operates by moving in an external circuit consisting of At the time of charging, lithium is released from the positive electrode active material and occluded in the negative electrode active material. At the time of discharging, lithium is released from the negative electrode active material and occluded in the positive electrode active material.

In order to further improve the battery capacity and energy density of a non-aqueous electrolyte secondary battery, a negative electrode active material or a positive electrode active material that can obtain a battery voltage of 3 V or more and can absorb and release more lithium is used. Need to develop.

Here, the battery voltage is generated by a potential difference between a positive electrode potential and a negative electrode potential (both are based on the same reference). Since the positive electrode potential is higher, at the time of discharging, current flows from the higher potential positive electrode to the lower potential negative electrode through an external circuit connected to a portable device or the like. The larger the potential difference, the higher the energy density. For example, about +4 in the positive electrode active material relative to LiCoO ₂ (Li / Li ⁺
V), graphite (about 0 to Li / Li ⁺ )
+ 0.5V), a battery voltage of about 3.5-4V is obtained. However, since the positive electrode potential decreases or the negative electrode potential increases with discharge, a phenomenon occurs in which the battery voltage decreases.

As the negative electrode active material used in the nonaqueous electrolyte secondary battery, lithium metal, lithium alloy, carbon material, composite oxide containing tin and the like have been proposed. In particular, non-aqueous electrolyte secondary batteries using a carbon material as a negative electrode active material are commercially available.

As the negative electrode active material, from the viewpoint of battery capacity and energy density, it is desirable to use metallic lithium because the amount of lithium contained per unit weight is the largest. However, when metal lithium is used as the negative electrode active material, lithium does not uniformly deposit on the negative electrode surface during charging, and dendrites, that is, dendrites, are generated, which penetrate the separator and short-circuit the negative electrode and the positive electrode. However, there is a risk that heat or fire may occur, which is extremely dangerous. In addition, when the dendrites are generated, the lithium metal is dropped or the charge / discharge cycle life is shortened.

In order to prevent such a phenomenon, use of a lithium alloy instead of lithium metal as a negative electrode active material has been studied. However, since the lithium alloy contains a large amount of aluminum or the like which does not participate in the charge / discharge reaction, the capacity per unit weight decreases. When a lithium alloy is used as the negative electrode active material, a phenomenon occurs in which the discharge proceeds and the negative electrode potential gradually increases to +2 V (relative to Li / Li ⁺ ). As described above, in a non-aqueous electrolyte secondary battery using a negative electrode active material whose negative electrode potential increases with discharge, when used as a power source for a portable device, etc., the battery voltage decreases as the battery is discharged. You have to start charging before using it to the end. That is, there is a problem that the battery capacity is substantially no different from a non-aqueous electrolyte secondary battery having a low battery capacity.

On the other hand, carbon with high crystallinity such as graphite,
Carbon materials such as low crystallinity carbon such as non-graphitizable carbon are used as negative electrode active materials for commercially available non-aqueous electrolyte secondary batteries. The nonaqueous electrolyte secondary battery using graphite as the negative electrode active material has a relatively small increase in the negative electrode potential in the initial and middle stages of discharge, and a sharp increase in the negative electrode potential in the end of discharge, so that the battery capacity can be used to some extent efficiently. . However, the capacity per unit weight of graphite (hereinafter simply referred to as capacity and distinguished from battery capacity) is actually 280 to
It is about 330 mAh / g and the theoretical capacity is 372 m
Because of the low Ah / g, there was a problem that the capacity could not be further increased. Further, graphite has poor wettability with the non-aqueous electrolyte, so that the non-aqueous electrolyte does not sufficiently impregnate the negative electrode active material, the reaction area is reduced, the capacity is reduced, and individual non-aqueous electrolytes are reduced. The problem that the performance of the secondary battery was different occurred. Furthermore, when graphite is used for the negative electrode active material,
There is a problem that the non-aqueous electrolyte is more easily decomposed than other carbon materials.

Carbon having low crystallinity, such as non-graphitizable carbon, has a carbon content of 400 to 700 mAh / g which exceeds the theoretical capacity of graphite.
It has been reported that it has a sufficient capacity. However, in such a carbon material, since the negative electrode potential (relative to Li / Li ⁺ ) keeps increasing with discharge, the battery voltage keeps decreasing during discharge when used in an actual non-aqueous electrolyte secondary battery. . Therefore, since the charging must be started before the battery capacity is completely used, the available capacity may be only about 300 mAh / g, which is almost equal to that of graphite.

On the other hand, in the Journal of Electrochemical Society, Vol. 140, No. 5, (1993), it has already been reported that lithium ions are reversibly inserted into SnO ₂ .

It has also been proposed to use a composite oxide containing tin as a negative electrode active material. For example, Japanese Unexamined Patent Publication
275268 Li _x SnO (X ≧ 0). In this patent, the capacity of the composite oxide is shown not per unit weight but per battery cell, and the amount of the negative electrode active material used in one battery cell is not clear,
Although it is not possible to make an accurate comparison, the capacity of the negative electrode active material is low, estimated from the capacity of the battery cell, and is considered to be 300 mAh / g or less. When the charge and discharge cycle is repeated, the capacity is extremely reduced.

Further, it has been proposed to use a powder of a composite oxide (such as SnSiO ₃ ) containing tin and germanium as a main component as a negative electrode active material.
For example, JP-A-6-338325 and JP-A-7-220721
And so on. In a non-aqueous electrolyte secondary battery using the composite oxide powder as a negative electrode active material, the negative electrode potential is higher than when a carbon material is used as the negative electrode active material, so that the battery voltage is slightly lower. Since the capacity that can be actually used is large, it is expected that a non-aqueous electrolyte secondary battery having a high capacity and a high energy density can be manufactured.

JP-A-6-338325 and JP-A-7-2207
A method for producing a composite oxide powder such as tin and silicon proposed in No. 21 or the like is a method utilizing the following solid-phase reaction method. First, SnO powder of tin source as raw material,
For example, dry-mixing a silicon source such as SiO ₂ powder and the like, put this mixed powder in a container such as a crucible, and perform calcination by mooring for about 10 hours or more at about 1000 ° C. using a calcination furnace such as an electric furnace, The powders are reacted in a solid state. As the reaction proceeds, the reaction product melts,
The melt is cooled, solidified, and pulverized to a powder.

However, as a result of additional tests by the present inventors on this manufacturing method, the powder obtained after sintering contained metallic tin or Sn.
Many unintended substances such as O ₂ and SiO ₂ were generated. That is, not all the mixed powders react uniformly, but the reaction is not uniform even in the same crucible, the yield of the target composite oxide is very poor, and the reproducibility is poor, so mass production cannot be performed. There were drawbacks. The reason why the yield is poor is that SnO used as a raw material is likely to sublimate at a high temperature, so that the amount scattered during firing is large, and the melt reacts with the crucible and adheres to the crucible, so that it cannot be removed. . Also, the reason for poor reproducibility is that SnO easily sublimates at high temperatures, so that the composition after firing tends to deviate from the charged composition, and reduction or oxidation occurs due to the oxygen concentration or reducing gas concentration in the atmosphere during firing. It is conceivable that it is difficult to control the atmosphere in which the target composite oxide can be produced with good reproducibility because metal tin and SnO ₂ are easily generated.

In order to cause the above-mentioned solid phase reaction, one
Since a long firing time of 0 hour or more is required, a large amount of energy is required.

On the other hand, in JP-A-7-235293,
Instead of using a solid phase reaction, a tin compound such as tin chloride is reacted with sodium hydroxide in an aqueous solution, and the resulting precipitate is calcined.
It describes that O ₂ powder is used as a negative electrode active material. In the method using this aqueous solution, the solubility of the tin compound in water is extremely small, and it is difficult to prepare an aqueous solution in which the tin compound is uniformly dissolved. An alkali containing an alkali metal such as sodium hydroxide or potassium hydroxide is used to further forcibly precipitate Sn (OH) ₄ . However, tin oxide powder obtained after calcining the precipitate contains a large amount of sodium, potassium, and the like, and these elements have an adverse effect such as reducing the capacity and increasing the variation in the capacity. Was. It is also conceivable to use ammonia water or the like instead of alkali such as sodium hydroxide or potassium hydroxide.However, since tin easily forms a complex with ammonia, it is difficult to adjust the pH value at which a precipitate is formed. Many,
Even if the precipitation can be generated by adjusting the pH value, a trace amount of ammonia or ammonium chloride remains in the powder after calcination, and this reacts with the non-aqueous electrolyte to reduce the capacity.

In the method using the above aqueous solution, the conductivity,
Antimony, which has the effect of improving the mechanical strength, charge / discharge cycle characteristics, etc., when producing tin oxide-based powders containing other constituent elements such as silicon, tin compounds used as raw materials, including antimony, silicon, etc. Since many compounds containing other constituent elements have very low solubility in water, it is very difficult to prepare an aqueous solution in which tin and other constituent elements such as antimony and silicon are uniformly dissolved. Was. Even if a uniform aqueous solution can be prepared, the product of the ion concentration of the constituent elements and the hydroxide ion concentration, that is, the value of the solubility product differs depending on the constituent elements,
When trying to form a precipitate by adding alkali,
A precipitate having an inhomogeneous composition, that is, a precipitate containing a large amount of tin or a precipitate containing a large amount of antimony, silicon, or the like is generated. The powder obtained by firing such a non-uniform precipitate becomes a mixture in which SnO ₂ and oxides of other constituent elements are completely phase-separated, and the conductivity, mechanical strength, charge / discharge cycle characteristics, etc. In addition to the above, there is a problem that the effect of improving the particle size cannot be obtained, the capacity of the powder after firing decreases, and the capacity varies. That is, in the method using the aqueous solution, it is very difficult to prepare a solution or powder in which tin and other constituent elements such as antimony and silicon are uniformly mixed at an atomic level and in an arbitrary ratio. Was.

[0021]

Therefore, a high-capacity tin oxide-based negative electrode active material for a non-aqueous electrolyte secondary battery can be produced in a high yield and with good reproducibility. Development of a manufacturing method that can be fired in a long time has been desired.

[0022]

Means for Solving the Problems The present inventors have intensively studied to solve the above technical problems. As a result, among the organic solvents, alcohol is used as a main solvent, in particular, alcohol-soluble tin compounds, metal tin, alcohol-soluble periodic table group 5 element compounds, alcohol-soluble periodic table group 15 element compounds, and other alcohol-soluble metal compounds. When a raw material such as an alcohol-soluble polymer compound is dissolved, a uniform and transparent precursor solution in which each constituent element is dissolved at an arbitrary ratio is obtained, and then concentrated, without causing non-uniform precipitation, Polymerization and condensation reactions occur without addition of an alkali that has an adverse effect such as a decrease in capacity, and a homogeneous powdery or fibrous gel without compositional irregularities can be produced. To produce high-capacity non-aqueous electrolyte secondary battery active materials with higher yield and higher reproducibility than before Preparative on can, furthermore found that can be produced by firing a short time of 10 hours, thereby completing the present invention herein.

That is, the present invention provides a tin oxide-based non-aqueous electrolyte characterized by dissolving an alcohol-soluble tin compound and / or metal tin in an alcohol to prepare a precursor solution, concentrating the solution, and then firing. This is a method for producing a negative electrode active material for a secondary battery.

Another invention relates to an alcohol-soluble tin compound and / or metal tin, and an alcohol-soluble group 5 element compound of the periodic table (the number of the group is a new IUPAC).
After dissolving the alcohol-soluble periodic table group 15 element compound to prepare a precursor solution,
A method for producing a negative electrode active material for a tin oxide-based non-aqueous electrolyte secondary battery, comprising concentrating and then firing.

Still another invention relates to alcohol-soluble tin compounds and / or metal tin in alcohol, alcohol-soluble silicon compounds, alcohol-soluble aluminum compounds, alcohol-soluble germanium compounds, alcohol-soluble titanium compounds, alcohol-soluble zirconium compounds, and alcohol-soluble magnesium. A precursor solution prepared by dissolving at least one alcohol-soluble metal compound selected from the group consisting of a compound and an alcohol-soluble boron compound, and then concentrating and then calcining the precursor solution. This is a method for producing a negative electrode active material for a water electrolyte secondary battery.

Still another invention relates to an alcohol-soluble tin compound and / or metal tin, an alcohol-soluble group 5 element compound and / or an alcohol-soluble group 15 element compound, an alcohol-soluble silicon compound and an alcohol. Soluble aluminum compounds, alcohol-soluble germanium compounds, alcohol-soluble titanium compounds, alcohol-soluble zirconium compounds,
Oxidation characterized by dissolving at least one alcohol-soluble metal compound selected from the group consisting of an alcohol-soluble magnesium compound and an alcohol-soluble boron compound to prepare a precursor solution, concentrating, and then calcining. This is a method for producing a negative electrode active material for a tin-based nonaqueous electrolyte secondary battery.

Next, the present invention will be described more specifically.

The negative electrode active material for a tin oxide-based nonaqueous electrolyte secondary battery of the present invention (hereinafter, also simply referred to as a tin oxide-based negative electrode active material)
In the production method, first, alcohol-soluble tin compounds, metal tin, alcohol-soluble periodic table group 5 element compounds, alcohol-soluble periodic table group 15 element compounds, other alcohol-soluble metal compounds, alcohol-soluble polymer compounds, etc. After preparing a solution in which the raw materials (hereinafter, these are collectively referred to as alcohol-soluble compounds) are dissolved, that is, a precursor solution, the solution is concentrated and then fired.

The precursor solution is prepared using an alcohol and an alcohol-soluble compound described below. In addition, concentration
This is performed for the purpose of preparing a high-viscosity precursor solution by removing excess alcohol in the precursor solution, or promoting polymerization and condensation reaction to gel. Specifically, the heating is performed by directly heating the container containing the precursor solution, or by using a concentrating device (for example, a rotary evaporator or the like) provided with a decompression device such as a vacuum pump. The concentrated high-viscosity precursor solution or gel is fired under the conditions described below.

The production method usually produces a tin oxide-based negative electrode active material in powder form. However, if it is desired to obtain a fibrous tin oxide-based negative electrode active material, it is concentrated so as to exhibit spinnability by concentration. After spinning the adjusted precursor solution,
The obtained fibrous gel (hereinafter referred to as gel fiber) may be fired. The fibrous tin oxide-based negative electrode active material is more easily penetrated by the nonaqueous electrolyte when constituting the nonaqueous electrolyte secondary battery, or even when the charge / discharge cycle is repeated, as compared with the powdery one. It is preferable because the tin oxide-based negative electrode active material has advantages such as hardly falling off or peeling off from the current collector.

In the present invention, the alcohol used for preparing the precursor solution is not limited as long as it dissolves various alcohol-soluble compounds described below. When these alcohols are represented by the general formula ROH, R is an unsubstituted alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an octyl group, a 2-methoxyethyl group, a 2-ethoxyethyl group, a 2-hydroxyethyl group. A substituted alkyl group such as a 1-methoxy-2-propyl group, a methoxyethoxyethyl group, a 2-phenylethyl group, a phenylmethyl group, an unsubstituted alkenyl group such as an allyl group; a 2-methyl-2-propenyl group; And a substituted alkenyl group such as a methyl-3-butenyl group.

Specific examples of the substituent in the above-mentioned substituted alkyl group, substituted alkenyl group and substituted aryl group include alkoxyl groups such as methoxy group and ethoxy group, hydroxyl group, phenyl group and the like, which are found in the above-mentioned specific examples of R. And an alkyl group such as an aryl group, a methyl group, and an ethyl group, and an amino group, a cyano group, a halogen atom such as a Cl atom, a Br atom, an I atom, and an F atom.

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 preferable because of high solubility of the alcohol-soluble compound. Methanol is particularly 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 alcohol-soluble compound.

The alcohol-soluble tin compound (hereinafter referred to as a tin compound) used in the present invention includes tin halide, organic tin and the like. The halogens of the tin halide are Cl, Br, I, and F atoms. Hydrates may also be used. Among the tin halide compounds, tin chloride and tin bromide are preferable in terms of price and stability. Specifically, SnCl ₂ , SnCl ₂ · 2H ₂₀ , SnBr ₂ , S
nI ₂ , SnF _2, etc., and in particular, SnCl ₂ , S
nBr ₂ and SnCl ₂ .2H ₂ O are preferably used.
Further, the tin halide compound modified with an organic compound, such as Sn (CH ₃ ) ₂ Cl ₂ , can also be used. (CH ₃ ) ₂ Sn, (C ₂
H _{5) 2} Sn, can be used or added in a range such that it dissolves and _{(C 3 H 7) 4 Sn} . Further, as the tin compound, a mixture of two or more kinds can be used.

The shape of the metal tin used in the present invention is not particularly limited, and may be plate-like, rod-like, sheet-like, granular, powdery, sandy,
Examples thereof include flower-like and lump-like ones, and from the viewpoint of ease of dissolution, granules, powders, and sands are preferred. The purity is preferably higher, but is not particularly limited as long as it does not affect the production method and does not affect the reproducibility of the specific resistance described later.

The mixing ratio of the alcohol and the tin compound and / or the metal tin in preparing the precursor solution is not particularly limited as long as the tin compound and / or the metal tin are uniformly dissolved in the alcohol. However, if the alcohol content is too small, the tin compound and / or metal tin will not completely dissolve, leaving insolubles, and a uniform precursor solution cannot be obtained. If the amount of alcohol is too large, the dissolution rate of the tin compound and / or metal tin increases, but it takes time for subsequent concentration and firing. Therefore, although it varies depending on the type of alcohol, tin compound and / or metal tin used, the mixing ratio is preferably such that the molar amount of alcohol is 2 to 100 times that of tin in terms of element. It is desirable that the mixing ratio be up to 50 times. However, when preparing the precursor solution, alcohol-soluble Group 5 element or Group 15 element element compound for imparting conductivity described below, or silicon, aluminum, germanium, titanium, zirconium, magnesium, boron When an alcohol-soluble metal compound is used, the mixing ratio is preferably such that the amount of alcohol is 2 to 100 times in molar ratio with respect to the total amount of tin and the other constituent elements in these alcohol-soluble compounds, Further, the mixing ratio is desirably 5 to 50 times.

In the present invention, in order to obtain a tin oxide-based negative electrode active material having high conductivity, a Group 5 element such as vanadium, niobium or tantalum, or a Group 15 element such as antimony or bismuth (hereinafter referred to as a Group 5 element) An alcohol-soluble periodic table group 5 element compound or an alcohol-soluble periodic table group 15 element compound (hereinafter collectively referred to as a conductivity-imparting element compound) containing a group 15 element is referred to as a conductivity-imparting element. It can be used as a raw material if necessary.

Examples of the compound for imparting conductivity include a vanadium compound, a niobium compound, a tantalum compound, an antimony compound, and a bismuth compound. Specifically, as the vanadium compound, VBr ₃ , VC
l ₂ , VCl ₃ , VCl ₄ , VOBr ₂ , VOBr ₃ , VO
_{Cl 3, VF 3, VF 4} , VF 5, VI 3 · 6H 2 O, vanadium alkoxides _{include, NbCl 5, NbBr 5, NbF} 5, NbOCl 3, etc. niobium alkoxides are mentioned as the niobium compound, TaBr ₅ , TaCl ₅ , tantalum alkoxide and the like as a tantalum compound, and SbCl ₃ ,
SbCl ₅ , SbBr ₃ , antimony oxychloride, alkoxides of antimony and the like, and further examples of bismuth compounds include BiCl ₃ , BiI ₂ and alkoxides of bismuth.

The above-mentioned compounds for imparting conductivity may each be dissolved alone in an alcohol or a precursor solution.
Alternatively, a plurality of them may be dissolved at the same time. When it is desired to impart conductivity, the compounding ratio of the conductivity-imparting element compound is 0.1% with respect to the total amount of tin and the conductivity-imparting element in terms of element.
２５25 mol% is preferred, and 2-10 mol% is more preferred. If the ratio is too low, the effect of imparting conductivity is small, and if it is too high, the effect of imparting conductivity is saturated.

In the present invention, silicon, aluminum, germanium, titanium, zirconium, magnesium, and boron (hereinafter collectively referred to) are used to improve the mechanical strength, capacity, charge / discharge cycle characteristics, etc. of the tin oxide-based negative electrode active material. Alkoxides, halides,
Alcohol-soluble compounds such as oxychloride, nitrate or sulfate (hereinafter collectively referred to as alcohol-soluble metal compounds) may be added as a part of the raw material.
Acetate can also be used as long as it is soluble in alcohol. The addition of these second elements also has the effect of improving the mechanical strength, particularly in the fibrous tin oxide-based negative electrode active material.

Examples of the alcohol-soluble metal compound of silicon (hereinafter referred to as silicon compound) include silicon alkoxide and silicon halide. Examples of the silicon alkoxide of the general formula _{Si (OR A) 4, R} B Si (O
_{R 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 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 And ethyltributoxysilane, ethyltripropoxysilane, vinyltriethoxysilane, allyltriethoxysilane, diphenyldimethoxysilane, dimethyldiethoxysilane, vinylmethyldiethoxysilane, diethyldimethoxysilane, ethylmethyldiethoxysilane, and the like. Examples of the silicon halide include SiCl ₄ , SiHCl ₃ , and SiH ₂ Cl ₂ .

An example of an alcohol-soluble metal compound of aluminum (referred to as an aluminum compound) is as follows.
_{AlCl 3, AlCl 3 · 6H 2} O, AlBr 3, AlBr
_{3 · 6H 2 O, AlI 3} , AlI 3 · 6H 2 O, Al (N
_{O 3) 3 · 9H 2 O} , Al (NO 3) 3 · 6H 2 O, aluminum alkoxides such as aluminum isopropoxide and the like.

The alcohol-soluble metal compound of germanium (referred to as a germanium compound) includes GeC
_{l 4, GeBr 2, GeBr 4} , such as germanium alkoxides such as tetraethoxy germanium and the like,
Alcohol-soluble metal compounds of titanium (referred to as titanium compounds) include TiCl ₄ , TiCl ₃ , TiCl ₂ ,
Examples include TiBr ₄ , TiBr ₄ .6H ₂ O, TiF ₄ , and titanium alkoxides such as tetraisopropoxytitanium. Examples of the alcohol-soluble metal compound of zirconium (referred to as zirconium compound) include ZrCl ₄ ,
_{Zr (NO 3) 4 · 5H} 2 O, ZrOCl 2 · 8H 2 O, Z
rOI ₂ · 8H ₂ O, include zirconium alkoxides such as tetrabutoxyzirconium, as the alcohol-soluble metal compounds of magnesium (as magnesium _{compound), MgCl 2 · 6H 2 O} , MgBr 2 · 6H 2
O, Mg (NO ₃ ) ₂ .nH ₂ O, magnesium alkoxide and the like. As alcohol-soluble metal compounds of boron (referred to as boron compounds), H ₂ B ₄ O ₇ ,
Examples include boron alkoxides such as H ₃ BO ₃ , HBF ₄ , BBr ₂ , and trimethoxyboron.

The alcohol-soluble metal compound does not need to be the compound from the beginning, but may be the compound in the alcohol or in the precursor solution at an early stage. For example, instead of using aluminum chloride, metal aluminum may be added to a precursor solution in which tin halide is dissolved for halogenation.

When the alcohol-soluble metal compound is a zirconium compound, the strength of the zirconium oxide generated in the tin oxide-based negative electrode active material is increased by stabilizing or metastabilizing the tetragonal or cubic zirconium oxide. Raw materials for rare earth oxides such as oxides of alkaline earth metals such as calcium oxide and magnesium oxide, yttrium oxide, cerium oxide, neodymium oxide, samarium oxide, gadolinium oxide, europium oxide, and scandium oxide to be included to enhance conductivity Raw materials that are soluble in alcohols such as alkoxides, chlorides, oxychlorides, nitrates, sulfates, and acetates of these elements can be used.

The above-mentioned alcohol-soluble metal compounds may be dissolved individually in an alcohol or a precursor solution, or a plurality of them may be dissolved simultaneously. The amount of the alcohol-soluble metal compound is not particularly limited and may be appropriately determined according to the purpose. In order to obtain a tin oxide-based negative electrode active material having a higher capacity, tin 2
For 0 to 99.99 mol%, the second element is 80 to 0.1%.
01 mol% is preferred.

Tin in the tin oxide-based negative electrode active material after firing,
The composition ratio of the conductivity-imparting element and the second element can be confirmed by chemical analysis or X-ray fluorescence analysis. However, in the production method of the present invention, the composition ratio of the element in the raw material and the tin oxide-based negative electrode active material after firing are usually used. Since the constituent ratios in the materials do not differ greatly, a tin oxide-based negative electrode active material having a desired composition can be obtained by adjusting the charged composition of the raw materials.

In the present invention, when it is desired to efficiently remove excess halogen during firing, or to obtain a fibrous tin oxide-based negative electrode active material, an alcohol-soluble polymer compound is added to the precursor solution. It is effective. As the alcohol-soluble polymer compound, any polymer compound soluble in alcohol can be used without any limitation. Specific examples include ethyl cellulose, cellulose acetate, cellulose nitrate, cellulose propionate, cellulose triacetate, acetylbutyl cellulose, celluloses such as hydroxylpropyl cellulose, polyvinyl butyral, polymethylene oxide, polyethylene oxide, polypropylene oxide, polyacetic acid. Vinyl and the like. By adding these alcohol-soluble polymer compounds, when the alcohol-soluble polymer compound is burned or decomposed by firing, it acts to remove halogen in the precursor solution as a combustion gas or a decomposition product gas, In addition, spinning is performed using a precursor solution whose viscosity has been adjusted by concentration, and when producing a tin oxide-based negative electrode active material in the form of a fiber, the viscosity and the drying speed are adjusted and the spinnability is improved. Has an effect of improving the spinning characteristics of the spinning, and spinning is facilitated.

The amount of the alcohol-soluble polymer compound to be added is preferably 0.01 to 20% by weight based on the total amount of the tin compound and the alcohol-soluble polymer compound. If the amount of the alcohol-soluble polymer compound is less than 0.01% by weight, a sufficient effect cannot be obtained. On the other hand, 20
If the amount exceeds 10% by weight, the effect is not only saturated, but also the alcohol-soluble polymer compound remains during firing, the amount of produced metal tin increases, and the capacity is undesirably reduced.

In spinning, a compound having two or more carboxyl groups such as acetylacetone, ethyl acetoacetate, diethyl malonate, or the like is used to improve the stability of the precursor solution whose viscosity has been adjusted by concentration. It may be appropriately contained as an agent, and it is also possible to add another compound to further improve the spinning characteristics.
The method for dissolving the alcohol-soluble compound in the alcohol is not particularly limited. For example, under stirring, a tin compound,
Metal tin, conductivity-imparting element compound, alcohol-soluble metal compound, and a method of dropping alcohol into a mixture of alcohol-soluble polymer compound, or under stirring, tin compound, metal tin, conductivity-imparting element compound in alcohol,
A method of simultaneously or sequentially dissolving the alcohol-soluble metal compound and the alcohol-soluble polymer compound can be used. In order to promote the dissolution of tin metal, it is also effective to reflux alcohol to dissolve tin metal.

Further, a small amount of water may be added in order to accelerate the hydrolysis reaction, polymerization and condensation reaction of the alcohol-soluble compound. The addition of water has effects such as sufficient progress of hydrolysis, polymerization and condensation reactions, particularly when preparing a precursor solution using an alcohol-soluble compound such as an alkoxide. However, if the amount of water to be added is too large, precipitation occurs or gelling occurs rapidly. The amount of water to be added is preferably 0.01 to 10 times in terms of mole of the alcohol-soluble compound, though it varies depending on the type of the alcohol-soluble compound.

When producing a fibrous tin oxide-based negative electrode active material, a volatile component such as alcohol contained in the precursor solution is evaporated and concentrated using a concentrating device such as a rotary evaporator to obtain a spinning property. After spinning, the precursor solution is adjusted to have a viscosity, that is, a spinning solution. The viscosity at this time varies depending on the type and amount of the conductivity imparting element and the second element, the diameter of the spinning nozzle, and the like.
~ 1000 poise is preferred.

The spinning method is not particularly limited, and a conventional spinning method can be used. For example, there is a method of extruding a spinning solution from a spinning nozzle. The length and diameter of the obtained fiber can be arbitrarily controlled by adjusting the viscosity of the spinning solution, the diameter of the spinning nozzle or the speed at which the spinning solution is extruded from the spinning nozzle, and the continuous fiber by winding. Is also possible.

In the case of producing a fibrous tin oxide-based negative electrode active material, it is more stable to prepare a precursor solution by using metal tin in addition to a tin compound as a tin source. In addition, the spun gel fibers can easily maintain their shape even in a high humidity atmosphere, furthermore, the adhesion of the gel fibers can be prevented, and the handling of the gel fibers becomes extremely easy, such as faster drying. preferable. Further, when producing a tin oxide-based negative electrode active material in any form of powder or fiber, when preparing a precursor solution using both a tin compound and metal tin,
Since the amount of halogen contained in the precursor solution can be adjusted by the amount of metal tin, the amount of halogen after firing can also be reduced.

The amount of metal tin is not particularly limited as long as it is within the range of dissolving in each charged composition. However, if the amount of metal tin is too large, it takes a long time to dissolve or may remain undissolved. Therefore, in a precursor solution in which an alcohol-soluble compound is dissolved, the conductivity-providing element compound and alcohol are contained in the precursor solution. When a soluble metal compound is not contained, the ratio of the number of atoms of halogen and tin, that is, X / Sn is set to 0.1.
When it is 60 or more and less than 1.80, and when it contains a conductivity-imparting element compound, the relationship between the number of atoms of halogen, tin, and the conductivity-imparting element is (0.60N _Sn + 0.65N _Y). ) ≦ X / (Sn + Y) <(1.
It is preferable to adjust so as to be 80N _Sn + 2.70N _Y ). Here, N _Sn is the ratio of the number of tin atoms in the precursor solution to the total number of tin atoms in the precursor solution, and N _Y is the number of tin atoms in the precursor solution. Is the ratio of the number of atoms of the conductivity-imparting element to the total amount of X, Sn, and Y each represent the number of atoms of halogen, tin, and the conductivity-imparting element in the precursor.

When an alcohol-soluble metal compound containing a halogen is further added, the halogen in the compound must be taken into consideration. That is, in the above formula, the number of atoms of the conductivity-imparting element may be replaced with the total number of atoms of the conductivity-imparting element and the second element.

In the case of producing a fibrous tin oxide-based negative electrode active material, the atomic ratio X / Sn of halogen and tin, or the relation X between the halogen and tin and the number of atoms of the conductivity-imparting element X
Even if / (Sn + Y) is larger than the above range, the gel fiber can be spun, but the obtained fiber is softened in a high-humidity atmosphere and its shape is easily broken, so that humidity control or the like is required. In addition, the atomic ratio X between the halogen and tin is represented by X
If / Sn or the relationship X / (Sn + Y) between the number of atoms of halogen and tin and the conductivity-imparting element is smaller than the above range, the spun gel fiber is stable even under high humidity, but it takes time to dissolve the metallic tin. However, there arises a problem that metal tin is not completely dissolved. Therefore, the atomic ratio X / Sn of halogen and tin, or halogen, tin,
It is preferable to control the relationship X / (Sn + Y) between the number of atoms of the conductivity-imparting element and the conductivity-imparting element within the above range.

It is to be noted that a simple substance of a conductivity-imparting element containing no halogen, such as antimony metal, is dissolved to form a halogen,
Relationship of the number of atoms of tin and the conductivity-imparting element X / (Sn +
The method of controlling Y) may be used in combination.

In the calcination of the present invention, volatile components such as alcohol and water in the concentrated high-viscosity precursor solution or in the dried powder, and in the gel fiber are removed or decomposed and burned, and the powder or fiber is baked. This is performed for the purpose of strengthening the skeleton and, in some cases, further crystallization. In particular, the gel fiber as spun from the spinning solution does not show sufficient mechanical strength as it is. High mechanical strength is achieved by firing gel fibers.

The sintering is performed using a sintering furnace or a sintering furnace such as a commercially available electric furnace or gas burner furnace. Above all, a firing furnace provided with a programmed temperature control function and a gas introduction / discharge function for controlling the atmosphere during firing is preferable.

The calcination is usually divided into a heating step, a mooring step for keeping the temperature constant, and a cooling step. When the heating rate is extremely slow, for example, the firing step is performed without going through the mooring step. It can also be performed in a step of cooling immediately. Furnace cooling is often performed after heating or mooring, while the powder or fiber is kept in the firing furnace.However, if the cooling rate is required to be extremely high, water can be used immediately after heating or mooring. Quenching method such as dipping in a solvent of the above or dropping on a rotating metal roll or the like.

Further, calcination may be performed in two or more steps for the purpose of efficiently removing the halogen in the precursor solution. For example, the temperature is raised from room temperature, once moored at 300 ° C. for 2 hours, and then raised again and moored at 500 ° C. for 2 hours.
After firing for 2 hours, another firing furnace B
And baking by mooring at 500 ° C. for 2 hours.

In the present invention, the firing temperature and the firing time refer to the mooring temperature and the mooring time during firing.

The firing temperature is preferably set so as to increase the capacity and to provide mechanical strength to the obtained powder or fiber. The firing temperature is preferably in the range of 100 to 1000 ° C., although it depends on the type and amount of the alcohol-soluble metal compound used. More preferably, a temperature of 200 to 700C is preferred. If the firing temperature is too low, alcohol, water, and the like remain in the fibers, resulting in a decrease in capacity and a failure to obtain sufficient mechanical strength. If the firing temperature is too high, the decomposition of tin oxide proceeds, the element that imparts conductivity sublimes, or the crystal grains in the fiber grow too much, increasing the specific resistance or decreasing the strength. This causes problems such as a decrease in capacity and a large amount of energy consumption.

If the firing time is too short, the firing is naturally insufficient. If the firing time is too long, the conductivity-imparting element sublimes or the crystal grains in the fiber grow too much, resulting in a low specific resistance. Problems such as an increase, a decrease in strength, a decrease in capacity, and a large consumption of energy occur. The firing time is preferably 0.03 to 8 hours, although it depends on the firing temperature, atmosphere and the like.

The heating rate during firing is not particularly limited.
If the firing is performed at an excessively slow heating rate, the conductivity-imparting element sublimes, or the crystal grains in the fiber grow too much, increasing the specific resistance or decreasing the strength,
Problems such as a decrease in capacity and a large consumption of energy occur. Also, if firing is performed at an excessively fast heating rate, the temperature in the furnace of the firing furnace exceeds the set temperature, a temperature distribution occurs in the furnace, and in the case of a fiber shape, the mechanical strength of the fiber decreases. Inconveniences such as Therefore, the heating rate is preferably 0.1 to 100 ° C./min.

The atmosphere during firing is not particularly limited. For example, helium, neon, inert gas such as argon, nitrogen gas, or hydrogen gas, reducing gas such as carbon monoxide gas, or air, oxygen gas, oxidizing gas such as water vapor, or a mixture thereof. There is a filled atmosphere and the like. However, the type of gas may be changed during firing. In firing under the above gas atmosphere,
It is preferable that the baking furnace be provided with a gas introduction and discharge function and the baking be performed while introducing the gas into the baking furnace, because a uniform tin oxide-based negative electrode active material is easily obtained. Further, firing may be performed in an atmosphere reduced in pressure by a vacuum pump or the like, or in an atmosphere in which the total pressure of the gas exceeds 1 atm, that is, in a pressurized state, but under a pressure of 0.01 to 5 atm. Performing the method is preferable because containers of special equipment such as a high vacuum container and a high pressure container are not required.

In the above calcination, even if calcination is performed before gelling, that is, in the state of a precursor solution having a high viscosity, a tin oxide-based negative electrode active material having a higher capacity than before can be obtained. Or, after concentrating and gelling, firing in the form of a dry powder can provide a more homogeneous product, and because the volatilization amount of alcohol during firing is small, safety is improved. Preferred for reasons.

The tin oxide-based negative electrode active material produced by the production method of the present invention depends on the heating rate of the firing, the firing temperature and the firing time, the type of atmosphere, the types and amounts of the conductivity imparting element and the second element, and the like. Although usually different, it usually has an amorphous structure, a structure with insufficient crystallization and close to an amorphous structure, a crystalline structure with sufficiently advanced crystallization, or a material having an amorphous structure and a crystal. A complex having such a structure that substances having a homogeneous structure are present at the same time. In general, when firing is performed at a low temperature or for a shorter time, substances having an amorphous structure or a structure close to an amorphous structure are increased. The structure of the tin oxide-based negative electrode active material can be determined by using a substance identification or structural analysis means such as X-ray diffraction analysis. For example, in the diffraction pattern of the X-ray diffraction analysis, when a substance having an amorphous structure is present, a halo is obtained near a diffraction angle 2θ = 20 to 40 °, and when a substance having a structure close to the amorphous structure is present, a half width is obtained. A broad diffraction peak having a large half-width (also referred to as a half width) is obtained, and a sharp diffraction peak having a very small half-width is obtained when a substance having a crystalline structure is present.

It is impossible to say unconditionally which material having an amorphous structure or a crystalline structure should be used more, but usually, a material having an amorphous structure or a structure close to an amorphous structure remains. The smaller the degree of crystallization of a substance having a structure close to the amorphous structure (as can be seen from the half width), the higher the capacity tends to be. However, the more the substance having a crystalline structure, the higher the conductivity. Since a tin oxide-based negative electrode active material having high conductivity can reduce the amount of a conductivity-imparting agent such as acetylene black when manufacturing a negative electrode of a nonaqueous electrolyte secondary battery, the capacity per unit weight of the negative electrode can be reduced. In addition to the increase, discharge with a larger current becomes possible. The structure may be selected according to the required performance of the tin oxide-based negative electrode active material, cost, and the like.

Some of the compounds which are difficult to analyze as to the conductivity-imparting element or the second element added as the conductivity-imparting element compound or the alcohol-soluble metal compound, and what kind of compound tin exists after firing, may be difficult. Yes, the present inventors do not know exactly all, but usually, oxides, carbides, or oxides remaining in a state where the modifying groups contained in alcohol-soluble metal compounds and the like are insufficiently decomposed. Or a complex of these.

For example, when calcined at a high temperature, tin exists as tin oxide (tin dioxide, tin monoxide, etc.), and the conductivity-imparting element and the second element form a solid solution in tin oxide. Often. Here, the solid solution refers to, for example, a state in which a conductivity-imparting element or a second element is substituted for tin atoms in tin oxide, or a state in which the element has penetrated into the crystal structure of tin oxide, that is, another substance B is contained in solid A. Refers to a state in which is uniformly dissolved, and a solid in that state is called a solid solution.

However, when the amount of the conductivity-imparting element or the second element is large, spinodal decomposition or the like occurs, and the conductivity-imparting element or the second element that cannot be completely dissolved in tin oxide is in a state of an oxide or the like. , And two or more phases may be present in a composite structure with a microscopic structure.
However, in this case, since the size of the two or more phases is very small, the structure has an amorphous structure or a structure close to the amorphous structure as judged by X-ray diffraction analysis.

In the case of firing at a low temperature, the modifying groups contained in the tin compound, the conductivity-imparting element compound, the alcohol-soluble metal compound and the like remain in an insufficiently decomposed state as carbon or the like, and form a carbide or carbon. May have an amorphous structure such as an oxide containing. On the other hand, the dried powder or gel fiber before firing is sufficiently dried in a vacuum or the like to disperse the alcohol, and then fired, or in an atmosphere having an oxygen concentration equal to or higher than the oxygen or partial pressure of oxygen in the air (for example, When calcination is performed in oxygen), carbon is sufficiently removed at the time of calcination to form an oxide with almost no residual carbon. However, if the calcination temperature at this time is low, a tin oxide-based negative electrode active material having an amorphous structure is used. Easy to become a substance.

The composition of each of the constituent elements in the tin oxide-based negative electrode active material produced by the production method of the present invention can be determined by using a quantitative analyzer such as a fluorescent X-ray or the like in which the molar ratio of each of the constituent elements is known in advance. In the sample, the relationship between the peak intensity ratio of the characteristic X-ray obtained from each constituent element and the molar ratio of each constituent element, i.e., the calibration curve was determined, and the composition of the peak intensity ratio of the unknown sample was measured and the calibration curve was determined. You can ask.

The value of the specific resistance of the tin oxide-based negative electrode active material of the present invention depends on the type of the conductivity-imparting element, the amount added, the firing atmosphere,
Although it greatly varies depending on the sintering temperature and the sintering time, it can usually take a value of 10 ³ to 10 ⁻² Ω · cm.
Further, when firing in an atmosphere of a reducing gas such as hydrogen gas or carbon monoxide gas, a value of 10 ⁻⁴ Ω · cm can be obtained.

The tin oxide-based negative electrode active material produced by the production method of the present invention can be suitably used for a non-aqueous electrolyte secondary battery. An outline of a method for manufacturing a nonaqueous electrolyte secondary battery using a tin oxide-based negative electrode active material is as follows.

First, the tin oxide-based negative electrode active material of the present invention and a binder are kneaded with a solvent such as N-methylpyrrolidone using a kneader, a mixer, or the like, to produce a paste. The binder may be first kneaded with the solvent, and then the tin oxide-based negative electrode active material may be kneaded. After the paste is manufactured, the current collector is coated or impregnated with the paste, the solvent is dried and removed, and then pressure, 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.

[0079]

According to the production method of the present invention, a high-capacity anode active material for a tin oxide-based non-aqueous electrolyte secondary battery can be obtained in a high yield.
In addition to having the effect of being able to be manufactured with good reproducibility, and also being able to be manufactured by firing for a short time of 10 hours or less, there is an effect that less energy is required. Therefore, the production method of the present invention is an industrially useful production method.

The advantages of the production method of the present invention in terms of yield, reproducibility and short calcination time compared to the production method utilizing the solid-phase reaction method are that alcohol before use in calcination The constituent elements of the tin oxide-based negative electrode active material are uniformly mixed at the atomic level without forming a precipitate,
The polymerization and condensation reactions proceed sufficiently at room temperature, and there is no need to react the raw materials with each other by calcination at high temperature and for a long time unlike the solid-phase reaction method. It is considered that separation, decomposition, sublimation, and the like hardly occur.

The reason why the tin oxide-based negative electrode active material produced by the production method of the present invention has a high capacity is as follows.
Although the present inventors have not fully understood, it is estimated as follows.

The tin oxide-based negative electrode active material produced by the production method of the present invention is uniformly mixed at the atomic level without precipitating the constituent elements of the tin oxide-based negative electrode active material in alcohol before firing. Since the polymerization and condensation reaction between the constituent elements have sufficiently proceeded at room temperature, there is little phase separation or decomposition after firing.
Therefore, it is considered that the capacity was improved because there were almost no phases or decomposition products not involved in the charge / discharge reaction.

Further, since the tin oxide-based negative electrode active material produced by the production method of the present invention does not go through a molten state,
The increased capacity of the tin oxide-based negative electrode active material involved in the charge / discharge reaction due to the porous nature and the good penetration of the nonaqueous electrolyte is also considered to be a factor in the capacity improvement.

Further, among the tin oxide-based negative electrode active materials produced by the production method of the present invention, 200 to 400
Some of them show high capacity even when fired at a low temperature of about ℃, but this is due to the fact that the alkoxy group in the alcohol or alcohol-soluble compound used as the raw material remains in the form of carbon etc. even after firing and forms pores. It is also thought that it caused the formation of a tin oxide-based negative electrode active material having a structure that can occlude and release more lithium,
Not clear.

[0085]

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

In the following Examples and Comparative Examples, the capacity of the negative electrode active material was measured as follows.

The calcined negative electrode active material (in the case of powder, once ground in a mortar), polyvinylidene fluoride (binder), and acetylene black (conductivity-imparting agent) were mixed with 80/5/15.
(Weight ratio), 1 ml of N-methylpyrrolidone as a solvent was added to 500 mg of this mixture, and kneaded to form a paste. This paste was dried in a vacuum dryer at 100 ° C. for 24 hours. 6 mg of the kneaded material containing the negative electrode active material was applied to a nickel net to obtain 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 as 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 a clipped nickel wire (covered with a glass tube) from the lid.

Using a charge / discharge device (manufactured by Hokuto Denko), a charge / discharge cycle test of the simple battery cell was performed to measure the capacity of the negative electrode active material. 30m in charge / discharge cycle test
The test was performed at a current value (constant) corresponding to A / g. The 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. The capacities in the examples and comparative examples were compared based on capacities at the time of the first discharge.

In order to confirm the reproducibility of the production method, the same precursor solution was fired five times, and the products in both fired products were compared by X-ray diffraction analysis. Were prepared and subjected to a charge / discharge cycle test to compare the capacities. In these five measurements of capacity, the one with the highest capacity was obtained as the negative electrode active material A, and the one with the lowest capacity was obtained as the negative electrode active material B. The results are shown in Tables 1 and 2. .

Further, the composition analysis of the tin, the conductivity-imparting element, and the second element after firing was carried out using a calibration curve prepared in advance using fluorescent X-ray analysis. In addition, the mol% of the conductivity imparting element and the second element in Tables 1 and 2 are values with respect to the total amount of tin and each element.

The yield after firing is calculated based on the weight (W ₀ ) of the oxide of the tin, the conductivity imparting element and the second element calculated from the charged amount and the composition, and the weight of the fired product obtained after firing. It was calculated from the ratio of (W). That is, the following equation was used.

Yield = (W / W ₀ ) × 100 (unit:%) A higher yield is an industrially useful production method.

EXAMPLE 1 7.55 g (0.04 mol) of stannous chloride (SnCl ₂ ) and 4.75 g (0.04 mol) of metallic tin were refluxed in 38.5 g (1.20 mol) of methanol. Then, the precursor solutions were sequentially dissolved to prepare a uniform and transparent precursor solution.
At this time, the relationship between the number of moles of chlorine and tin is Cl / Sn = 1.
It is.

The above precursor solution was concentrated to obtain a dry powder. The dried powder is placed in a commercial electric furnace in air for 5 minutes.
Five batches were fired at 00 ° C. for 2 hours. As a result of performing X-ray diffraction analysis of the obtained five fired products, all were Sn
Since broad diffraction peaks of O _{2 from} the (110) and (101) planes were detected, Sn close to an amorphous structure was detected.
It was found that O ₂ was generated.

Using the above five fired products, five simple battery cells were prepared, and a charge / discharge cycle test was performed. Table 1 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 2 To 40.5 g (1.26 mol) of methanol, 7.58 g (0.04 mol) of stannous chloride (SnCl ₂ ), 4.75 g (0.04 mol) of tin metal, and trichloride Antimony (S
0.96 g (0.0042 mol) of bCl ₃ were sequentially dissolved while refluxing to prepare a uniform and transparent precursor solution. At this time, the relationship between the mole numbers of chlorine, tin, and antimony is: Cl / (Sn + Sb) = 1.10 0.60N _Sn + 0.65N _Sb = 0.60 1.80N _Sn + 2.70N _Sb = 1.85 .

The precursor solution was concentrated to obtain a dry powder. The dried powder is placed in a commercial electric furnace in air for 5 minutes.
Five batches were fired at 00 ° C. for 2 hours. As a result of performing X-ray diffraction analysis of the obtained five fired products, all were Sn
Since broad diffraction peaks of O _{2 from} the (110) and (101) planes were detected, Sn close to an amorphous structure was detected.
It was found that O ₂ was generated. Further, since no diffraction peak of antimony oxide was detected, it was found that antimony oxide was dissolved in SnO _{2 having an} amorphous structure. From the fluorescent X-ray analysis, the relationship between the mole numbers of tin and antimony was Sb / (Sn + Sb) = 0.
05, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were prepared, and a charge / discharge cycle test was performed. Table 1 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 3 7.55 g (0.04 mol) of stannous chloride (SnCl ₂ ) and 4.75 g (0.04 mol) of metallic tin were refluxed in 38.5 g (1.20 mol) of methanol. After sequentially dissolving while stirring, tetraethoxysilane (Si (0
16.7 g (0.08 mol) of C ₂ H ₅ ) ₄ ) was added to prepare a uniform and transparent precursor solution. At this time, the relationship between the number of moles of chlorine and tin is Cl / Sn = 1.

The precursor solution was concentrated to obtain a dry powder. The dried powder was calcined in argon for 5 hours at 200 ° C. for 2 hours using a commercially available electric furnace. As a result of X-ray diffraction analysis of the obtained five fired products, a halo was detected in each case, indicating that powder having an amorphous structure containing Sn and Si was generated. From the fluorescent X-ray analysis, the relationship between the mole numbers of tin and silicon was
/(Sn+Si)=0.50, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were produced, and a charge / discharge cycle test was performed. Table 1 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 4 After the same precursor solution as in Example 3 was prepared, it was concentrated to obtain a dry powder. Using a commercially available electric furnace,
The mixture was calcined in argon at 500 ° C. for 2 hours for 5 batches. X-ray diffraction analysis the results of the five fired product obtained, both the spread diffraction peak from the SnO ₂ (110) plane and (101) plane, the diffraction angle 2 [Theta] = 20 to 40
Since a halo was detected in the vicinity of °, it is considered that a complex of SnO ₂ close to the amorphous structure and a substance having another amorphous structure was formed. In addition, from fluorescent X-ray analysis,
The relationship between the number of moles of tin and silicon is Si / (Sn + Si) =
0.50, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were prepared and subjected to a charge / discharge cycle test. Table 1 shows the results. Each of the negative electrode active materials had a very high capacity and yield. Met.

Example 5 To 38.5 g (1.20 mol) of methanol was added 11.1 g (0.04 mol) of stannous bromide (SnBr ₂ ) and 4.75 g (0.04 mol) of metal tin. After sequentially dissolving while fluxing, tetraethoxysilane (Si (0
16.7 g (0.08 mol) of C ₂ H ₅ ) ₄ ) was added to prepare a uniform and transparent precursor solution. At this time, the relationship between the number of moles of bromine and tin is Br / Sn = 1.

The precursor solution was concentrated to obtain a dry powder. This dried powder was calcined in an argon atmosphere at 500 ° C. for 5 hours in a commercial electric furnace for 5 hours. As a result of X-ray diffraction analysis of the obtained five fired products, a halo was detected in each case, indicating that powder having an amorphous structure containing Sn and Si was generated. From the fluorescent X-ray analysis, the relationship between the mole numbers of tin and silicon was
/(Sn+Si)=0.50, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were manufactured, and a charge / discharge cycle test was performed. Table 1 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 6 To 55.3 g (1.20 mol) of ethanol, 7.58 g (0.04 mol) of stannous chloride (SnCl ₂ ), 4.75 g (0.04 mol) of tin metal, and Sb ( OC ₂ H ₅ ) ₃ 1.
08 g (0.0042 mol) were successively dissolved while refluxing to prepare a uniform and transparent precursor solution. At this time, the relationship between the molar numbers of chlorine, tin, and antimony is: Cl / (Sn + Sb) = 0.95 0.60N _Sn + 0.65N _Sb = 0.60 1.80N _Sn + 2.70N _Sb = 1.85 .

The above precursor solution was concentrated to obtain a dry powder. This dried powder was calcined in an argon atmosphere at 500 ° C. for 5 hours in a commercial electric furnace for 5 hours. X-ray diffraction analysis of the obtained five fired products showed that in all cases, a broad diffraction peak from the (110) plane and the (101) plane of SnO ₂ was detected. _It turned out that ₂ was generated. Further, since no diffraction peak of antimony oxide was detected, it was found that antimony oxide was dissolved in SnO _{2 having an} amorphous structure. From the fluorescent X-ray analysis, the relationship between the mole numbers of tin and antimony was Sb / (Sn + Sb) =
0.05, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were manufactured, and a charge / discharge cycle test was performed. Table 1 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 7 The procedure of Example 4 was repeated, except that the same mole of 2-ethoxyethanol was used instead of 38.5 g (1.20 moles) of methanol, and the atmosphere during firing was air. Was. As a result of performing X-ray diffraction analysis of the obtained five fired products, all of the (110) face and (10) face of SnO ₂ were obtained.
1) Diffraction of diffraction peak from plane and diffraction angle 2θ = 20
Since a halo was detected at about 40 °, it is considered that a complex of SnO ₂ close to the amorphous structure and a substance having another amorphous structure was generated. Also, from the fluorescent X-ray analysis, the relationship between the number of moles of tin and silicon was found to be Si / (Sn + S
i) = 0.50, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were manufactured, and a charge / discharge cycle test was performed. Table 1 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 8 0.96 g (0.00%) of antimony trichloride (SbCl ₃ )
Instead of the same mole of tantalum pentachloride (Ta).
The same procedure as in Example 2 was carried out except that Cl ₅ ) was used and the atmosphere during firing was argon. At this time, the relationship between the number of moles of chlorine, tin, and tantalum is: Cl / (Sn + Ta) = 1.20 0.60N _Sn + 0.65N _Ta = 0.60 1.80N _Sn + 2.70N _Ta = 1.85 .

X-ray diffraction analysis of the obtained five baked products showed that in all cases, broad diffraction peaks from the (110) plane and the (101) plane of SnO ₂ were detected. it was found that the SnO ₂ is generating close to. Further, since no diffraction peak of tantalum oxide was detected, tantalum oxide had an S structure close to an amorphous structure.
It was found that it was dissolved in nO ₂ . From the fluorescent X-ray analysis, the relationship between the number of moles of tin and tantalum was found to be Ta.
/(Sn+Ta)=0.05, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were prepared and subjected to a charge / discharge cycle test. Table 1 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 9 0.96 g (0.00%) of antimony trichloride (SbCl ₃ )
Instead of the same mole of niobium pentachloride (NbC
using l _5), the atmosphere during firing, except that the argon was carried out in the same manner as in Example 2. At this time, the relationship between the number of moles of chlorine, tin, and niobium is as follows: Cl / (Sn + Nb) = 1.20 0.60N _Sn + 0.65N _Nb = 0.60 1.80N _Sn + 2.70N _Nb = 1.85 .

As a result of X-ray diffraction analysis of the obtained five fired products, broad diffraction peaks from the (110) and (101) planes of SnO ₂ were detected. it was found that the SnO ₂ is generating close to. In addition, since no diffraction peak of niobium oxide was detected, niobium oxide was formed of SnO 2 having an amorphous structure.
₂ was found to be in solid solution. From the fluorescent X-ray analysis, the relationship between the mole numbers of tin and niobium was Nb / (S
n + Nb) = 0.05, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were manufactured and subjected to a charge / discharge cycle test. Table 1 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 10 16.7 g of tetraethoxysilane (Si (0C ₂ H ₅ ) ₄ )
(0.08 mol) instead of aluminum chloride (Al
Example 3 was repeated except that 1.07 g (0.008 mol) of Cl ₃ was used. At this time, the relationship between the number of moles of chlorine and tin is Cl / Sn = 1.30.

As a result of X-ray diffraction analysis of the obtained five fired products, broad diffraction peaks from the (110) and (101) planes of SnO ₂ were detected. It was found that SnO ₂ having a crystalline structure was generated. In addition, from fluorescent X-ray analysis,
The relationship between the number of moles of tin and aluminum is Al / (Sn + A
l) = 0.09, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were prepared and subjected to a charge / discharge cycle test. Table 1 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

[0121]

[Table 1]

Example 11 16.7 g of tetraethoxysilane (Si (0C ₂ H ₅ ) ₄ )
Instead of (0.08 mol), 2.02 g (0.008 mol) of tetraethoxygermanium (Ge (0C ₂ H ₅ ) ₄ ) was used, and the amount of methanol was doubled to 77.0 g (2.4).
0 mol) in the same manner as in Example 4.
At this time, the relationship between the number of moles of chlorine and tin is Cl / Sn = 1.
It is.

As a result of X-ray diffraction analysis of the obtained five fired products, broad diffraction peaks from the (110) and (101) planes of SnO ₂ were detected. It was found that SnO ₂ having a crystalline structure was generated. In addition, from fluorescent X-ray analysis,
The relationship between the number of moles of tin and germanium is Ge / (Sn + G
e) = 0.09, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were manufactured and subjected to a charge / discharge cycle test. Table 2 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 12 16.7 g of tetraethoxysilane (Si (0C ₂ H ₅ ) ₄ )
Instead of (0.08 mol), tetrabutoxytitanium (Ti (0C ₄ H _{9) 4)} 2.72 g except using (0.008 mol) was carried out in the same manner as in Example 4. At this time, the relationship between the number of moles of chlorine and tin is Cl / Sn = 1.

X-ray diffraction analysis of the obtained five calcined products revealed that the diffraction peaks spread from the (110) and (101) planes of SnO ₂ were detected. It was found that SnO ₂ having a crystalline structure was generated. In addition, from fluorescent X-ray analysis,
The relationship between the number of moles of tin and titanium is Ti / (Sn + Ti) =
0.09, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were prepared and subjected to a charge / discharge cycle test. Table 2 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 13 16.7 g of tetraethoxysilane (Si (0C ₂ H ₅ ) ₄ )
Instead of (0.08 mol), tetrabutoxyzirconium (Zr (0C ₄ H _{9) 4)} 3.07 g except using (0.008 mol) was carried out in the same manner as in Example 4. At this time, the relationship between the number of moles of chlorine and tin is Cl / Sn = 1.

As a result of X-ray diffraction analysis of the obtained five fired products, a broad diffraction peak was detected from the (110) and (101) planes of SnO _2. It was found that SnO ₂ having a crystalline structure was generated. In addition, from fluorescent X-ray analysis,
The relation between the number of moles of tin and zirconium is Zr / (Sn + Z
r) = 0.09, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were prepared and subjected to a charge / discharge cycle test. Table 2 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 14 16.7 g of tetraethoxysilane (Si (0C ₂ H ₅ ) ₄ )
(0.08 mol) instead of magnesium chloride (Mg
Example 4 was repeated except that 0.76 g (0.008 mol) of Cl ₂ was used. At this time, the relationship between the mole numbers of chlorine and tin is Cl / Sn = 1.20.

As a result of X-ray diffraction analysis of the obtained five fired products, a broad diffraction peak was detected from the (110) plane and the (101) plane of SnO _2. It was found that SnO ₂ having a crystalline structure was generated. In addition, from fluorescent X-ray analysis,
The relationship between the number of moles of tin and magnesium is Mg / (Sn + M
g) = 0.09, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were prepared and subjected to a charge / discharge cycle test. Table 2 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 15 16.7 g of tetraethoxysilane (Si (0C ₂ H ₅ ) ₄ )
(0.08 mol) instead of trimethoxyboron (B
(0CH ₃ ) ₃ ) The procedure of Example 4 was repeated except that 0.83 g (0.008 mol) was used. At this time, the relationship between the number of moles of chlorine and tin is Cl / Sn = 1.

As a result of X-ray diffraction analysis of the obtained five fired products, broad diffraction peaks from the (110) and (101) planes of SnO ₂ were detected. It was found that SnO ₂ having a crystalline structure was generated. From the fluorescent X-ray analysis, the relation between the number of moles of tin and boron was B / (Sn + B) = 0.0
9 and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were produced, and a charge / discharge cycle test was performed. Table 2 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 16 The amount of tetraethoxysilane (Si (0C ₂ H ₅ ) ₄ ) was set to 1.
The same operation as in Example 4 was carried out except that the amount was changed to 67 g (0.008 mol). At this time, the relationship between the number of moles of chlorine and tin is Cl / Sn = 1.

As a result of X-ray diffraction analysis of the obtained five fired products, broad diffraction peaks from the (110) and (101) planes of SnO ₂ were detected. It was found that SnO ₂ having a crystalline structure was generated. In addition, from fluorescent X-ray analysis,
The relationship between the number of moles of tin and silicon is Si / (Sn + Si) =
0.09, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were manufactured, and a charge / discharge cycle test was performed. Table 2 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 17 To 40.5 g (1.26 mol) of methanol, 7.58 g (0.04 mol) of stannous chloride (SnCl ₂ ), 4.75 g (0.04 mol) of tin metal, and trichloride Antimony (S
0.96 g (0.0042 mol) of bCl ₃ were sequentially dissolved while refluxing, and 16.7 g (0.08 mol) of tetraethoxysilane (Si (0C ₂ H ₅ ) ₄ ) was further added. A homogeneous and clear precursor solution was prepared. At this time, the relationship between the mole numbers of chlorine, tin, and antimony is: Cl / (Sn + Sb) = 1.10 0.60N _Sn + 0.65N _Sb = 0.60 1.80N _Sn + 2.70N _Sb = 1.85 .

The precursor solution was concentrated to obtain a dry powder. This dried powder was calcined in an argon atmosphere at 500 ° C. for 5 hours in a commercial electric furnace for 5 hours. As a result of performing X-ray diffraction analysis of the obtained five baked products, it was found that the diffraction peaks spread from the (110) plane and the (101) plane of SnO ₂ , and that a halo appeared near the diffraction angle 2θ = 20 to 40 °. From the detection, it is considered that a complex of SnO ₂ close to the amorphous structure and a substance having another amorphous structure was formed. Further, since no diffraction peak of antimony oxide was detected, it was found that antimony oxide was dissolved in a complex of SnO ₂ having a structure close to the amorphous structure and a substance having another amorphous structure. Also, from the fluorescent X-ray analysis, the relationship between tin and antimony, and the mole number of tin and silicon,
Sb / (Sn + Sb) = 0.05, Si / (S
n + Si) = 0.50, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were manufactured and subjected to a charge / discharge cycle test. Table 2 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 18 7.55 g (0.04 mol) of stannous chloride (SnCl ₂ ) and 4.75 g (0.04 mol) of tin metal were refluxed in 38.5 g (1.20 mol) of methanol. After sequentially dissolving while stirring, tetraethoxysilane (Si (0
16.7 g (0.08 mol) of C ₂ H ₅ ) ₄ ) and 0.06 g of polyethylene oxide having an average molecular weight of 2,000,000 were added to prepare a uniform and transparent precursor solution. At this time, the relationship between the number of moles of chlorine and tin is Cl / Sn = 1.

The above precursor solution was concentrated to obtain a dry powder. The dried powder is placed in a commercial electric furnace in air for 5 minutes.
Five batches were fired at 00 ° C. for 2 hours. As a result of performing X-ray diffraction analysis of the obtained five fired products, all were Sn
Since the diffusion peaks of O _{2 from} the (110) plane and the (101) plane and a halo were detected at a diffraction angle 2θ of about 20 to 40 °, SnO ₂ close to an amorphous structure and another non-crystalline layer were detected. It is considered that a complex of substances having a crystalline structure was formed. From the fluorescent X-ray analysis, the relationship between the mole numbers of tin and silicon is Si / (Sn + Si) = 0.50,
There was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were prepared and subjected to a charge / discharge cycle test. Table 2 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 19 To a mixture of 384.5 g (12.0 mol) of methanol, 75.8 g (0.4 mol) of stannous chloride (SnCl ₂ ) and 47.5 g (0.4 mol) of metal tin were refluxed. Then, the precursor solutions were sequentially dissolved to prepare a uniform and transparent precursor solution. At this time, the relationship between the number of moles of chlorine and tin is Cl / Sn = 1.

The above precursor solution was concentrated and adjusted to a viscosity of 33 poise to obtain a spinning solution. This spinning solution was spun using a nozzle having a number of holes. The obtained gel fibers were fired in air at 500 ° C. for 2 hours for 5 batches. The average diameter of five fiber obtained is about 29 .mu.m, was subjected to X-ray diffraction analysis of the fibers results, both of SnO ₂ (1
Spread diffraction peaks from the (10) and (101) planes were detected, indicating that SnO ₂ close to an amorphous structure was generated.

Using the above five fibers, five simple battery cells were prepared and subjected to a charge / discharge cycle test. Table 2 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

Example 20 To 403.7 g (1.26 mol) of methanol, 75.8 g (0.4 mol) of stannous chloride (SnCl ₂ ), 47.5 g (0.4 mol) of metallic tin, and trichloride Antimony (Sb
9.58 g (0.042 mol) of Cl ₃ were sequentially dissolved while refluxing, and then 16.7 g (0.08 mol) of tetraethoxysilane (Si (0C ₂ H ₅ ) ₄ ) was further dissolved.
Was added to prepare a uniform and transparent precursor solution. At this time, the relationship between the mole numbers of chlorine, tin, and antimony is: Cl / (Sn + Sb) = 1.10 0.60N _Sn + 0.65N _Sb = 0.60 1.80N _Sn + 2.70N _Sb = 1.85 .

The above precursor solution was concentrated and adjusted to a viscosity of 30 poise to obtain a spinning solution. This spinning solution was spun using a nozzle having a number of holes. The obtained gel fibers were baked in argon at 500 ° C. for 2 hours for 5 batches. The average diameter of the obtained five fibers was about 33 μm. As a result of performing X-ray diffraction analysis of the fibers, all of the fibers showed a broad diffraction peak from the (110) plane and the (101) plane of SnO ₂ , and a diffraction angle. Since a weak halo was detected at around 2θ = 20 to 40 °, it is considered that a complex of SnO ₂ close to an amorphous structure and a substance having another amorphous structure was generated. In addition, since no diffraction peak of antimony oxide was detected, antimony oxide was found to have a SnO structure close to an amorphous structure.
_The solid solution was found to be dissolved in a complex of ₂ and another substance having an amorphous structure. Further, from the fluorescent X-ray analysis, the relations of the mole numbers of tin and antimony and tin and silicon were Sb / (Sn + Sb) = 0.05 and Si / (Sn + S
i) = 0.50, and there was no deviation from the charged composition.

Using the above five fired products, five simple battery cells were manufactured and subjected to a charge / discharge cycle test. Table 2 shows the results. Each of the negative electrode active materials had a very high capacity and yield.

[0152]

[Table 2]

Comparative Example 1 The above-described simplified battery cell was prepared using commercially available graphite as a negative electrode active material.
And a charge / discharge cycle test was performed. Table 3 shows the results.

The capacity when the above graphite was used as the negative electrode active material was very low as compared with the tin oxide type negative electrode active material of the present invention.

Comparative Example 2 Five simple battery cells were manufactured using commercially available SnO powder as a negative electrode active material, and a charge / discharge cycle test was performed. Table 3 shows the results.

When the SnO powder was used as the negative electrode active material, the capacity was lower than that of the tin oxide-based negative electrode active material of the present invention.

Comparative Example 3 A commercially available SnO ₂ powder was fired in air at 500 ° C. for 2 hours for 5 batches, and then the above-mentioned five simplified battery cells were prepared as negative electrode active materials, and a charge / discharge cycle test was conducted. Table 3 shows the results.

The capacity when the above SnO ₂ powder was used as the negative electrode active material was larger than that of the tin oxide type negative electrode active material of the present invention.
It was low.

Comparative Example 4 75.8 g of stannous chloride (SnCl ₂ ) per liter of water
(0.4 mol) was added and stirred for 1 hour. At this time, the solution was cloudy. Thereafter, sodium hydroxide was gradually added to generate a precipitate of tin hydroxide. The precipitate obtained by filtration was dried and then calcined in air at 500 ° C. for 2 hours for 5 batches.

[0160] The results obtained are subjected powder X-rays diffraction analysis, both of SnO ₂ (110) plane and (10
1) Since a weak diffraction peak from the plane was detected, it is considered that SnO ₂ close to an amorphous structure was generated. From the fluorescent X-ray analysis, the relationship between the molar numbers of tin and sodium was Na / (Sn + Na) = 0.04.

Using the obtained fired product as a negative electrode active material, five simple battery cells were prepared and subjected to a charge / discharge cycle test. Table 3 shows the results.

The capacity when the above SnO ₂ powder was used as the negative electrode active material was larger than that of the tin oxide type negative electrode active material of the present invention.
It was low.

Comparative Example 5 10.8 g (0.08 g) of commercially available tin monoxide (SnO) powder
Mol) and 4.81 g of silicon dioxide powder (SiO ₂ )
(0.08 mol) in a mortar for 5 minutes. This mixed powder was put into an alumina crucible,
5 batches were baked at 12 ° C. for 12 hours. After firing, there were traces of some melting, and the fired product was attached to the crucible, and it was difficult to collect the fired product as it was. Therefore, the yield was calculated from the difference between the weight of the baked product as it was on the crucible and the weight of the crucible. Then, with a metal spoon,
The attached fired product was collected, and the obtained fired product was pulverized.

[0164] The results obtained are subjected powder X-rays diffraction analysis, both of SnO ₂ (110) plane and (10
1) Strong diffraction peak from plane, Sn (200) plane,
(101) plane, (220) plane, (211) plane, (30) plane
1) plane, (112) plane, (400) plane, (321) plane,
Since diffraction peaks from the (420) plane, the (411) plane, and the like, and a weak halo near a diffraction angle of 2θ = 20 to 40 ° were detected, SnO ₂ , tin having a crystalline structure and tin having an amorphous structure were detected. It is considered that a mixture of SiO ₂ was formed. From the fluorescent X-ray analysis, the relationship between the number of moles of tin and silicon is Si / (Sn + Si) = 0.55,
The composition was different from the charged composition.

Using the fired powder, five simple battery cells were prepared and subjected to a charge / discharge cycle test. Table 3 shows the results.

When the powder after firing was used as a negative electrode active material, the capacity was smaller than that of the tin oxide-based negative electrode active material of the present invention.
It was low. Also, the yield was low.

Comparative Example 6 75.8 g of stannous chloride (SnCl ₂ ) per liter of water
(0.4 mol) and stirred. At this time, the solution was cloudy. Then, tetraethoxysilane (Si (0C ₂
H _{5) 4)} was added 83.3 g (0.4 mol), and stirred. Immediately after the addition of tetraethoxysilane, the solution was separated into two phases, and a precipitate was formed and the amount increased with stirring. After stirring for 24 hours, sodium hydroxide was gradually added to further generate a precipitate. The precipitate obtained by filtration is dried and then dried in air at 500
The mixture was baked at 5 ° C. for 2 hours for 5 batches.

[0168] The results obtained are subjected powder X-rays diffraction analysis, both of SnO ₂ (110) plane and (10
1) Weak diffraction peak from plane and diffraction angle 2θ = 20-4
Since a weak halo was detected near 0 °, it is considered that SnO ₂ close to the amorphous structure and SiO ₂ having the amorphous structure were generated. Also, from the fluorescent X-ray analysis, the relationship between the mole numbers of tin and sodium and between tin and silicon was Na / (Sn + Na) = 0.02 and Si / (Sn
+ Si) = 0.50.

Using the obtained fired product as a negative electrode active material, five simple battery cells were prepared and subjected to a charge / discharge cycle test. Table 3 shows the results.

When the fired product was used as a negative electrode active material, the capacity was very low as compared with the tin oxide-based negative electrode active material of the present invention.

[0171]

[Table 3]

Claims (6)

[Claims] 1. A tin oxide-based non-aqueous electrolyte secondary battery characterized in that a precursor solution is prepared by dissolving an alcohol-soluble tin compound and / or metal tin in alcohol, and then concentrated and then fired. A method for producing a negative electrode active material. 2. A precursor solution is prepared by dissolving an alcohol-soluble tin compound and / or metal tin, and an alcohol-soluble Group 5 element compound and / or an alcohol-soluble Group 15 element compound in an alcohol. ,
A method for producing a negative electrode active material for a tin oxide-based nonaqueous electrolyte secondary battery, comprising concentrating and then firing. 3. Alcohol-soluble tin compound and / or metal tin as alcohol, alcohol-soluble silicon compound, alcohol-soluble aluminum compound, alcohol-soluble germanium compound, alcohol-soluble titanium compound, alcohol-soluble zirconium compound, alcohol-soluble magnesium compound, and alcohol At least one selected from the group consisting of soluble boron compounds
A method for producing a negative electrode active material for a tin oxide-based non-aqueous electrolyte secondary battery, comprising preparing a precursor solution by dissolving various kinds of alcohol-soluble metal compounds, concentrating the solution, and then firing the solution. 4. An alcohol-soluble tin compound and / or metal tin, an alcohol-soluble group 5 element compound and / or an alcohol-soluble group 15 element compound, an alcohol-soluble silicon compound, an alcohol-soluble aluminum compound, Alcohol-soluble germanium compound, alcohol-soluble titanium compound,
Dissolving at least one alcohol-soluble metal compound selected from the group consisting of an alcohol-soluble zirconium compound, an alcohol-soluble magnesium compound, and an alcohol-soluble boron compound to prepare a precursor solution, concentrating, and then firing. A method for producing a negative electrode active material for a tin oxide-based non-aqueous electrolyte secondary battery, comprising the steps of: 5. The precursor solution according to claim 1, further comprising an alcohol-soluble polymer compound dissolved therein.
5. The method for producing a negative electrode active material for a tin oxide-based non-aqueous electrolyte secondary battery according to 4. 6. A negative electrode active material for a tin oxide-based non-aqueous electrolyte secondary battery obtained by the production method according to claim 1.