JP3526695B2 - Positive electrode for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel positive electrode for a non-aqueous electrolyte secondary battery, and a non-aqueous electrolyte secondary battery using the same.

[0002]

2. Description of the Related Art With the rapid reduction in size and weight of electronic devices in recent years, there has been a demand for a small size, lightweight secondary battery having a high energy density. There are various possible secondary batteries that meet these requirements, but non-aqueous electrolyte secondary batteries are particularly promising.

As a non-aqueous electrolyte secondary battery, LiMn ₂
Capable of occluding and releasing a positive electrode having a positive electrode active material composed of a composite oxide of lithium and a transition metal such as O ₄ , LiCoO ₂ , LiNiO ₂ , Li ₂ MnO ₄ and lithium such as lithium metal or carbon material Non-aqueous electrolysis obtained by dissolving a negative electrode having a negative electrode active material composed of a substance, and an electrolyte composed of a lithium salt such as LiClO ₄ or LiPF _{6 in} a non-aqueous solvent such as propylene carbonate, ethylene carbonate or 1,2-dimethoxyethane. An example of the secondary battery includes a separator that separates the liquid from the positive and negative electrodes. Since this non-aqueous electrolyte secondary battery uses a non-aqueous solvent for the electrolyte, an electromotive force equal to or higher than the decomposition voltage of water can be obtained, and the energy density can be greatly increased.

A composite oxide of lithium and a transition metal is generally used for the positive electrode active material used in this non-aqueous electrolyte secondary battery. However, such a material has poor conductivity, and it is difficult to use the material alone. Therefore,
Generally, a carbon material such as graphite or acetylene black is added as a conductivity-imparting agent for the purpose of improving conductivity. By adding a carbon material such as graphite or acetylene black to the composite oxide, the conductivity was improved and the composite oxide became practically usable as a positive electrode active material.

However, when graphite powder is added as a conductivity-imparting agent to the positive electrode active material, the adhesion between the graphite particles is not so good, and therefore the positive electrode active material is pressed to have sufficient conductivity. It is pressed by a machine to increase its adhesion and make a positive electrode. However,
When the positive electrode active material is pressure-molded in this manner, the pores between the particles of the positive electrode active material are collapsed, and the nonaqueous electrolytic solution cannot be sufficiently impregnated into the positive electrode active material. As a result, the contact area between the non-aqueous electrolyte solution and the positive electrode active material is remarkably reduced, and diffusion of lithium ions becomes extremely difficult, resulting in a problem of low utilization rate.

Further, although the secondary battery uses a non-aqueous electrolyte, it contains several to several tens of ppm of water as an impurity, which decomposes during charge / discharge cycles to generate oxygen gas. This oxygen reacts with the carbon material that is the conductivity-imparting agent to become carbon dioxide gas and volatilize. That is, by repeating the charge / discharge cycle, the positive electrode active material gradually loses and consumes the carbon material that is the conductivity-imparting agent, and accordingly, the conductivity of the positive electrode active material decreases and the utilization rate thereof decreases. There was a problem. Among the carbon materials, acetylene black was particularly worn out.

Further, the positive electrode active material expands / contracts due to the occlusion and release of lithium during the charge / discharge cycle, and particularly when the deep charge / discharge cycle is repeated, the positive electrode active material is miniaturized, and as a result, the positive electrode active material There are problems such as collapse and poor adhesion to the current collector, resulting in poor current collection.

Further, in order to increase the electric capacity, it is desired to increase the proportion of the positive electrode active material in the positive electrode, but if the carbon material as the conductivity-imparting agent is excessively reduced, the positive electrode becomes conductive. Loses the utilization rate. Further, if the amount of the binder is reduced too much, the strength cannot withstand the expansion and contraction of the electrode that occurs during the charge / discharge cycle, and the phenomenon such as the collapse of the positive electrode active material occurs, increasing the proportion of the positive electrode active material. There was a limit.

[0009]

Therefore, even if the charge / discharge cycle is repeated for a long period of time, the conductivity is not lost, and the expansion / contraction of the electrode that occurs during the charge / discharge cycle does not cause the current collection failure and the binding. There has been a strong demand for a positive electrode for a non-aqueous electrolyte secondary battery in which the positive electrode active material does not collapse even if the amount of the agent is small and the high utilization rate is maintained.

[0010]

[Means for Solving the Problems] The inventors of the present invention have conducted extensive studies to solve the above technical problems. As a result, a positive electrode for a non-aqueous electrolyte secondary battery in which a positive electrode active material containing a tin oxide fiber in a material capable of inserting and extracting lithium is joined to a current collector is used for a long period of time. Conductivity is not lost even if the discharge cycle is performed, current collection failure does not occur due to expansion / contraction of the electrode that occurs during the charge / discharge cycle, and the positive electrode active material does not collapse even if the amount of the binder is small, which is high. The inventors have found that the utilization rate is maintained, have completed the present invention, and have proposed the present invention.

That is, the present invention is characterized in that a positive electrode active material containing tin oxide fibers in a material capable of inserting and extracting lithium is joined to a current collector. The present invention relates to a positive electrode for a liquid secondary battery. Another invention is that the positive electrode for a non-aqueous electrolyte secondary battery and a negative electrode formed by joining a negative electrode active material made of a material capable of absorbing and releasing lithium to a current collector are non-aqueous electrolytic via a separator. The present invention relates to a non-aqueous electrolyte secondary battery, which is housed in a container together with a liquid.

The present invention will be described in detail below.

In the non-aqueous electrolyte secondary battery of the present invention, the non-aqueous electrolyte, the positive electrode active material that constitutes the positive electrode, the negative electrode active material that constitutes the negative electrode, and the separator are not particularly limited, and any known ones can be used. Can be used.

A material capable of inserting and extracting lithium is used as the positive electrode active material, and specifically, Ti is used.
Sulfides such as S ₂ , MoS ₂ and FeS ₂ , chalcogen compounds such as selenides such as NbSe ₃ , or Cr ₂ O ₅ and Cr
_{3 O 8, V 3 O 8} , V 2 O 5, V 6 O 13 oxide of a transition metal such _{as, LiMn 2 O 4, Li 2} MnO 4, LiV 3 O 5, LiN
Composite oxides of lithium and a transition metal such as iO ₂ and LiCoO ₂ and the like, conjugated polymers such as polyaniline, polyacetylene, polyparaphenylene, polyphenylene vinylene, polypyrrole and polythiophene, crosslinked polymers having a disulfide bond, etc. Can be mentioned.

In the present invention, the above-mentioned lithium occlusion,
It is characterized in that tin oxide fibers are contained in the positive electrode active material that can be released.

As the negative electrode active material, a material capable of inserting and extracting lithium is used. Specifically, metallic lithium, Li-Al alloy, Li-Pb-Cd-B is used.
Examples thereof include alloys such as i alloys and carbon materials such as graphite.

As the non-aqueous electrolyte, propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone,
Tetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methylsulfolane, acetonitrile, propionitrile, etc. alone or in a mixture of two or more kinds of non-aqueous solvents,
LiClO ₄ , LiPF ₆ , LiAsF ₆ , LiBF ₄ , L
iB (C ₆ H ₅ ) ₄ , LiCl, LiBr, CH ₃ SO ₃ L
A non-aqueous electrolyte solution in which a lithium salt such as i or CF ₃ SO ₃ Li is dissolved can be used in any combination.

Any separator can be used without any limitation as long as it has a low resistance to the movement of ions and is excellent in solution retention. For example, a glass fiber filter, a polymer pore filter such as polypropylene, polyethylene, polyester, or polyflon, a non-woven fabric, or a glass fiber filter and a non-woven fabric composed of these polymers can be used. Further, it is preferable to use a material that melts and closes the pores to prevent a short circuit between the positive and negative electrodes when the temperature inside the battery becomes high.

The tin oxide fibers preferably used in the present invention include fiber shapes having a diameter in the range of 1 to 50 μm and a length to diameter ratio, that is, an aspect ratio of more than 10. Here, the diameter is the diameter of the cross section of the tin oxide fiber in the direction perpendicular to the length direction when the cross section is circular, and is the average of the short diameter and the long diameter when the cross section is elliptical. In the case of a triangle, the average of three sides is used, and in the case of a polygon of quadrangle or more, the average of two or more diagonal lines is used.

The diameter and length values are at least 10
The average value of at least one tin oxide fiber is used. The diameter and length can be easily measured by using a photograph of the tin oxide fiber taken by a scanning electron microscope, an optical microscope or the like equipped with a photography device.

The tin oxide in the tin oxide fiber is tin dioxide (S
nO ₂ ), tin monoxide (SnO), and tin oxide having oxygen defects (SnO _2-x , where 0 <x <1) exist as tin oxides, and a plurality of tin oxides having different chemical compositions are mixed. There are also things I do. Which chemical composition of tin oxide is contained in the tin oxide fiber depends on manufacturing conditions such as an atmosphere during firing. For example, in an oxidizing atmosphere such as oxygen and air during firing, most of tin oxide is tin dioxide, or tin oxide fibers having a high tin dioxide content are obtained. In addition, an inert atmosphere such as argon gas or helium gas,
Alternatively, in a non-oxidizing atmosphere such as a reducing atmosphere such as carbon monoxide, tin monoxide and tin oxide having oxygen defects are contained in addition to tin dioxide, and most of tin oxide is tin monoxide or oxygen defects. It becomes a tin oxide fiber which is a tin oxide having. Among them, tin oxide fibers in which most of tin oxide is tin dioxide are preferable because they have high mechanical strength.

The amount of tin oxide in the tin oxide fiber is preferably 60 mol% or more, more preferably 70 mol% or more in order to improve the conductivity.

As other components in the tin oxide fiber, there are a doping component for controlling conductivity, an additive component for improving mechanical strength, etc., and a plurality of doping components or additive components are added. It doesn't matter. However, if a component other than tin oxide, such as a doping component or an additive component, is added in a too large amount, the conductivity and the mechanical strength are deteriorated. Therefore, the doping component and /
Alternatively, it is desirable that the total amount of the added components does not exceed the amount of tin oxide, that is, less than 50 mol%.

Examples of the doping component include oxides containing elements of Group 15 (new IUPAC system) of the Periodic Table such as antimony and bismuth, and oxides containing Group 5 elements such as vanadium and niobium. Among these, antimony oxide is preferable because it has a very high effect of improving conductivity.

The optimum amount of the doping component is selected depending on the performance and cost of the non-aqueous electrolyte secondary battery. Generally, if the amount is too small, the effect of improving the conductivity is small and the amount is too large. If it is too large, the cost will rise, or phase separation or the like will occur, resulting in inconvenience such as reduction in mechanical strength. Therefore, the amount of the doping component is 0.1 to the total number of moles of tin and the doping component.
30 mol% is desirable, and 1 to 10 mol% is more preferable.

On the other hand, as the additive component, an oxide containing a Group 2 element such as calcium or magnesium, a Group 3 element such as yttrium or lanthanoid (elements having atomic numbers 57 to 71 such as lanthanum and cerium) is used. Oxides containing, oxides containing Group 4 elements such as titanium and zirconium, oxides containing Group 5 elements such as vanadium and niobium, oxides containing Group 6 elements such as chromium, manganese, etc. An oxide containing a Group 7 element, an oxide containing a Group 12 element such as zinc, an oxide containing a Group 13 element such as aluminum or indium,
There are oxides containing a Group 14 element such as silicon and germanium, oxides containing a Group 15 element such as antimony and bismuth, and the like. Of these, oxides containing Group 14 elements (excluding tin) such as silicon and germanium,
An oxide containing a Group 13 element such as aluminum or indium, or an oxide containing a Group 4 element such as titanium is preferable because it has a high effect of improving mechanical strength.

The optimum amount of the additive component is selected each time according to the performance and cost of the non-aqueous electrolyte secondary battery.
In general, if the amount is too large, phase separation or the like occurs, which rather causes inconvenience such as reduction in mechanical strength. Therefore, the amount of the additive component is preferably 40 mol% or less, and more preferably 30 mol% or less with respect to the total number of moles of tin and the additive component. However,
The additive component may not be added.

The shape of the tin oxide fiber is not particularly limited, but if the length is too short, when added to the positive electrode active material,
Since the effect of imparting conductivity is small, the tin oxide fiber preferably has an aspect ratio of 10 or more. Further, if the diameter of the tin oxide fiber is too large, the flexibility is lost and the strength decreases. If it is too small, the handling becomes difficult and the strength becomes insufficient. Therefore, the diameter of the tin oxide fiber is 1 to 50 μm. Preferably there is. If the cross section of the tin oxide fiber in the direction perpendicular to the length is polygonal, stress concentrates at the corners, which may reduce the strength of the positive electrode. Therefore, it is more desirable that the shape of the cross section of the tin oxide fiber in the direction perpendicular to the length direction is circular or elliptical.

The tin oxide fiber is made of amorphous, polycrystalline, or single crystal tin oxide, although it varies depending on the production conditions. However, the doping component or additive component may be phase-separated. The structure of the tin oxide fiber can be confirmed by X-ray diffraction analysis or the like. For example, in the case of amorphous, the X-ray diffraction pattern becomes halo. Further, in the case of polycrystal, an X-ray diffraction pattern of tin oxide or a phase-separated doping component or addition component appears.

The specific resistance of the tin oxide fiber largely changes depending on the type of the doping component, the addition amount, the manufacturing conditions, etc. However, if the specific resistance is too large, the effect of imparting conductivity is lost, so that 10 ³ -10 ^{− 2} Ω · cm is desirable 10 ²
More preferably, 10 ⁻² Ω · cm.

If the amount of tin oxide fibers added to the positive electrode active material is too small, the effect of imparting conductivity will be small, and if it is too large, the proportion of the amount of the positive electrode active material will decrease. However, the electric capacity of the positive electrode rather decreases. The addition amount of the tin oxide fiber is preferably 1 to 40% by weight, based on the total amount of the tin oxide fiber, the positive electrode active material and the binder, and 5 to 3%.
0% by weight is more preferred.

A positive electrode having a positive electrode active material containing tin oxide fibers is typically manufactured as follows. First, using a kneader, a mixer or the like, a powder of a composite oxide of lithium and a transition metal and tin oxide fibers are kneaded with a solvent such as N-methylpyrrolidone, and a paste of a positive electrode active material containing tin oxide fibers. To manufacture. It is also possible to first knead the composite oxide of lithium and transition metal and the solvent, and then knead with the tin oxide fiber. After the paste is manufactured, the current collector is coated with the paste, impregnated with it, and the solvent is dried. Then, the paste is pressed and cut to be processed into a desired shape to obtain a positive electrode. The tin oxide fibers may be crushed or cut to some extent during the production of the paste, but if the aspect ratio is 10 or more, the effect is hardly impaired. Further, since the tin oxide fiber produced by the solution method has excellent flexibility, it is easy to maintain a high aspect ratio.

In the present invention, the tin oxide fiber may be manufactured by any method. For example, a solution method produced from a solution containing a tin oxide precursor, a sputtering method in which a target containing tin oxide is sputtered under argon plasma and tin oxide is deposited on a substrate having grooves, It is produced by a precipitation method or the like in which a tin compound such as tin or tin is heated and sublimated in a closed container or a container close to a closed state and recrystallized as whiskers of tin oxide (tin oxide). Among them, the solution method is preferable because the diameter and the length of the tin oxide fiber can be easily controlled, the mass productivity is excellent, and the yield is high.

The solution method is, for example, Japanese Patent Application No. 7-33.
The method described in 5547 or Japanese Patent Application No. 7-255395 is often used. The outline is as follows.

A tin compound such as tin halide or metallic tin, and a compound containing a doping component and an additive component are sequentially dissolved in alcohol such as methanol. After dissolution, unnecessary organic solvent is concentrated under reduced pressure to give a viscous spinning solution. The spinning solution is extruded or sucked out from a nozzle having a large number of holes each having a diameter of several μm to several mm to perform spinning to obtain gel fiber, and then firing is performed at a temperature of about 500 to 1000 ° C.

The tin oxide fibers having a high aspect ratio maintain their electrical conductivity without considering the contact between the tin oxide fibers, and as a result, the pressure applied by the press machine can be reduced. If the pressing force at the time of molding the positive electrode active material is low, sufficient pores remain in the positive electrode active material, and as a result, the nonaqueous electrolytic solution can be sufficiently impregnated in the positive electrode active material. Furthermore, since the tin oxide fiber has good wettability with the non-aqueous electrolyte, the wettability of the positive electrode active material with the non-aqueous electrolyte is improved.

Further, even if the tin oxide fiber is placed under a severe oxidation potential during a charge / discharge cycle, it does not undergo oxidative decomposition and does not deteriorate in performance such as conductivity. Therefore, the positive electrode to which the tin oxide fiber is added has an excellent charge / discharge cycle life as compared with the case where a carbon material such as acetylene black is added.

If the tin oxide fiber has an aspect ratio of a certain value or more than its shape, it becomes a material having excellent flexibility. When such a material is added to the positive electrode, even if the electrode expands or contracts during the charge / discharge cycle, the reinforcing effect of the tin oxide fiber makes it possible to provide a stable electrode.
As a result, the charge / discharge cycle life can be extended.

Further, the tin oxide fiber has good entanglement with the positive electrode active material, and increases the proportion of the positive electrode active material in the positive electrode in order to increase the electric capacity, and instead reduces the amount of the binder. However, it has sufficient strength and does not easily collapse even if the positive electrode expands or contracts by repeating a charge-discharge cycle for a long time.

[0040]

INDUSTRIAL APPLICABILITY The non-aqueous electrolyte secondary battery positive electrode to which the tin oxide fiber of the present invention is added does not lose its conductivity even after a long-term charging / discharging cycle, and the expansion of the electrode generated during the charging / discharging cycle. -Even when contracted, current collection failure does not occur, and the positive electrode active material does not collapse even if the amount of the binder is small, which has the effect of maintaining a high utilization rate.

[0041]

EXAMPLES Examples will be shown below, but the present invention is not limited thereto.

In the following examples and comparative examples, propylene carbonate was used as the non-aqueous solvent. Lithium salt is lithium perchlorate, which is
It was dissolved so as to have a mol / liter to obtain an electrolytic solution. As the battery cell, a stainless steel bottom plate with a polytetrafluoroethylene cylindrical portion installed was used, the positive electrode was installed on the lower bottom plate, and the negative electrode and the reference electrode were used by being hung from the upper lid. . A commercially available charging / discharging device (made by Hokuto Denko) to measure the charging / discharging cycle characteristics of the positive electrode active material.
Then, the utilization rate of the positive electrode active material was measured. The charge / discharge current density was set to 12.7 μA / cm ² and +
Charging was terminated when the voltage reached 4.3 V, and discharging was terminated when the voltage reached +3.0 V with respect to the reference electrode. Thereafter, the charge / discharge test was repeated under the same conditions. However, a rest of 1 hour was taken after each of charging and discharging. At this time,
LiCoO ₂ was used as the positive electrode active material, polytetrafluoroethylene (hereinafter referred to as PTFE) was used as the binder, tin oxide fiber, acetylene black or commercially available spherical tin oxide powder was used as the conductivity-imparting agent, and these were mixed and then pressed. It was pressed into pellets with a machine to obtain a positive electrode. Lithium metal was used for the negative electrode and the reference electrode. A polypropylene microporous film was used as a separator to surround the negative electrode. Here, the utilization rate is a value for only the active material. Specifically, the theoretical electric capacity of the positive electrode active material (LiCoO ₂ ),
It was calculated from the weight of the positive electrode active material used in the sample and the amount of discharged electricity by the following calculation formula.

[0043]

[Equation 1]

The utilization factor at the 100th discharge is divided by the utilization factor at the first discharge and multiplied by 100 to obtain 1
The capacity retention rate at the 00th cycle was used for comparison.

The tin oxide fibers used in the examples were manufactured by the following method.

639.0 g of stannous chloride (SnCl ₂ ),
549.6 g of metal tin and 95.8 g of antimony chloride were sequentially dissolved in 3942 g of methanol. The obtained solution was concentrated by a rotary evaporator to obtain a spinning solution. This spinning solution is spun from a nozzle having many holes,
Gel fibers were made. This gel fiber was fired at 700 ° C. for 2 hours and then cut to have an average fiber diameter of 27 μm, an aspect ratio of 20 (tin oxide fiber A), an aspect ratio of 50 (same B),
A tin oxide fiber having an aspect ratio of 200 (same as C) and a tin oxide fiber having an average fiber diameter of 300 μm and an aspect ratio of 20 (same as D) were obtained. As a result of elemental analysis by a calibration curve using a fluorescent X-ray, the Sn / Sb molar ratio was 94.9 / 5.1. The cross section perpendicular to the length direction was circular.

Example 1 500 mg (77.5% by weight) of LiCoO ₂ , 16 mg (2.5% by weight) of PTFE as a binder, and tin oxide fiber A1
29 mg (20% by weight) was mixed to obtain a positive electrode active material, which was pressure-molded on a current collector (made of copper) with a press machine to produce a positive electrode. A battery cell was assembled as described above and a charge / discharge test was conducted. The results are shown in Table 1.

Example 2 500 mg (77.5% by weight) of LiCoO ₂ , 16 mg (2.5% by weight) of PTFE as a binder and tin oxide fiber B1
29 mg (20% by weight) was mixed to obtain a positive electrode active material, which was pressure-molded on a current collector (made of copper) with a press machine to produce a positive electrode. A battery cell was assembled as described above and a charge / discharge test was conducted. The results are shown in Table 1.

Example 3 500 mg (77.5% by weight) of LiCoO ₂ , 16 mg (2.5% by weight) of PTFE as a binder, and tin oxide fiber C1
29 mg (20% by weight) was mixed to obtain a positive electrode active material, which was pressure-molded on a current collector (made of copper) with a press machine to produce a positive electrode. A battery cell was assembled as described above and a charge / discharge test was conducted. The results are shown in Table 1.

Comparative Example 1 LiCoO ₂ (500 mg, 75% by weight) was mixed with P as a binder.
33 mg (5% by weight) of TFE and 133 mg (20% by weight) of spherical tin oxide powder (average particle size 0.5 μm) were mixed to obtain a positive electrode active material, which was pressure-molded on a current collector (made of copper) with a press machine. A positive electrode was produced. A battery cell was assembled as described above and a charge / discharge test was conducted. The results are shown in Table 1.

Comparative Example 2 500 mg (77.5% by weight) of LiCoO ₂ was mixed with 16 mg (2.5% by weight) of PTFE as a binder and 129 mg (20% by weight) of spherical tin oxide powder to prepare a positive electrode active material,
A current collector (made of copper) was pressure-molded with a press machine to produce a positive electrode. A battery cell was assembled as described above and a charge / discharge test was conducted. The results are shown in Table 1.

Comparative Example 3 500 mg (90% by weight) of LiCoO _{2 was} mixed with P as a binder.
TFE 28 mg (5% by weight), acetylene black 28
mg (5% by weight) was mixed to obtain a positive electrode active material, which was pressure-molded on a current collector (made of copper) with a pressing machine to produce a positive electrode. A battery cell was assembled as described above and a charge / discharge test was conducted. The results are shown in Table 1.

[0053]

[Table 1]

Example 4 500 mg (87.5% by weight) of LiCoO ₂ , 14 mg (2.5% by weight) of PTFE as a binder and tin oxide fiber B5
7 mg (10% by weight) was mixed to obtain a positive electrode active material, which was pressure-molded on a current collector (made of copper) with a press machine to produce a positive electrode. A battery cell was assembled as described above and a charge / discharge test was conducted. The results are shown in Table 2.

Example 5 LiCoO ₂ (500 mg, 67.5% by weight), PTFE binder (19 mg, 2.5% by weight), tin oxide fiber B2
22 mg (30% by weight) was mixed to obtain a positive electrode active material, which was pressure-molded on a current collector (made of copper) with a press machine to produce a positive electrode. A battery cell was assembled as described above and a charge / discharge test was conducted. The results are shown in Table 2.

Comparative Example 4 500 mg (77.5% by weight) of LiCoO ₂ , 16 mg (2.5% by weight) of PTFE as a binder and tin oxide fiber D1
29 mg (20% by weight) was mixed to obtain a positive electrode active material, which was pressure-molded on a current collector (made of copper) with a press machine to produce a positive electrode. A battery cell was assembled as described above and a charge / discharge test was conducted. The results are shown in Table 2.

[0057]

[Table 2]

Continuation of front page (56) Reference JP-A-7-153495 (JP, A) JP-A-6-163051 (JP, A) JP-A-10-3904 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) H01M 4/00-4/62 H01M 10/40

Claims (3)

(57) [Claims] 1. A non-aqueous electrolyte secondary battery in which a positive electrode active material containing tin oxide fibers in a material capable of inserting and extracting lithium is bonded to a current collector. For positive electrode. 2. The positive electrode for a non-aqueous electrolyte secondary battery according to claim 1, wherein the tin oxide fiber has a diameter of 1 to 50 μm and an aspect ratio of 10 or more. 3. The positive electrode for a non-aqueous electrolyte secondary battery according to claim 1 or 2, and a negative electrode formed by joining a negative electrode active material made of a substance capable of absorbing and releasing lithium to a current collector. A non-aqueous electrolyte secondary battery, which is housed in a container together with a non-aqueous electrolyte via a separator.