JPH05290851A - Nonaqueous electrolyte battery - Google Patents

Abstract

PURPOSE:To provide a nonaqueous electrolyte battery having a large capacity by using litlnium-nickel composite oxide of which inclusion of lithium including less by-product is in a specific range for positive electrode active material. CONSTITUTION:A negative electrode 2 mainly comprising lithium metal or maternal capable of storage and discharge of lithium, and a positive electrode 1 using compound expressed by a composition formula of LixNiOy (1.15<=x<=1.75, y>0) for active material are provided. By thus using the positive electrode 1 using lithium-nickel composite oxide including less by-product at the time of manufacturing for the active material, a nonaqueous electrolytic battery of a large capacity can be provided. The compound expressed by the composition formula of LixNiOy shall preferably be mixture of lithium compound and nickel compound which are heat processed at 450-900 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte battery, and more particularly to an improvement of the positive electrode active material for the purpose of increasing the battery capacity of the non-aqueous electrolyte battery using a lithium-nickel composite oxide as the positive electrode active material. Regarding

[0002]

2. Description of the Related Art In recent years,
LiNiO ₂ has been proposed as a positive electrode active material for a non-aqueous electrolyte battery. This LiNiO ₂ (120 mAh /
g) has a smaller capacity than LiCoO ₂ (160 mAh / g), and this point has been a barrier to practical use.

Then, as a result of intensive studies on the reason why the capacity of LiNiO ₂ is so low, LiNiO ₂ has hitherto been obtained by mixing lithium hydroxide and nickel hydroxide at a molar ratio of 1: 1 and heat-treating them. Although produced, Li ₂ Ni ₈ O ₁₀ etc. are by-produced at this mixing ratio,
As a result, it was found that pure LiNiO ₂ was difficult to obtain.

The present invention has been made in view of the above circumstances, and an object thereof is to use a lithium-nickel composite oxide having a large capacity comparable to that of LiCoO ₂ as a positive electrode active material. There is a non-aqueous electrolyte battery provided.

[0005]

A non-aqueous electrolyte battery according to the present invention (hereinafter referred to as "the battery of the present invention") for achieving the above object is lithium metal or a substance capable of inserting and extracting lithium. With a negative electrode as a main component and a composition formula Li _X
A positive electrode using a compound represented by NiO _y (1.15 ≦ x ≦ 1.75, y> 0) as an active material.

The compound represented by the composition formula Li _X NiO _y , which is the positive electrode active material in the battery of the present invention, has a Li: Ni atomic ratio value, that is, a value of x in the composition formula of 1.15 to 1.
It is in the range of 75. The value of x is limited in this way, as shown in Examples described later, when the value of x is 1.15 to 1.75, the discharge capacity (150 m) is large.
Ah / g or more).

The compound represented by the above composition formula Li _x NiO _y is, for example, lithium hydroxide (LiOH) and nickel hydroxide (Ni (OH) ₂ ), and lithium hydroxide is added to 1 mol of nickel hydroxide. After mixing at a predetermined ratio of 1.15 to 1.75 mol, in air 450 to 900 ° C
It is obtained by heat treatment in. Incidentally, as a lithium compound that can be used as a lithium raw material, other lithium oxide, lithium carbonate, lithium nitrate, and the like, and as a nickel compound that can be used as a nickel raw material,
Other examples include nickel oxide, nickel carbonate, nickel nitrate and the like.

In the positive electrode of the present invention, the positive electrode active material thus obtained is pulverized to a predetermined particle size if necessary, and then a conductive agent such as acetylene black or carbon black and polytetrafluoroethylene (PTFE), A binder such as polyvinylidene fluoride (PVdF) and a weight ratio of 80 are usually used.
˜90: 5 to 15: 4 to 15 and mixed at a ratio of about 5 to form a positive electrode mixture, and then pressure-molded at a predetermined pressure (usually 0.5 to 2.5 ton / cm ² ). The molded product is rolled into a current collector and heat-treated (usually heated at about 100 to 250 ° C).

The negative electrode in the battery of the present invention is mainly composed of lithium metal or a substance capable of inserting and extracting lithium. When lithium metal is used, it is processed into a predetermined shape such as a disk shape by rolling, punching or the like and then used.

As a substance capable of inserting and extracting lithium,
Examples include lithium alloys and carbon materials such as graphite and coke. When a powdery substance such as a carbon material is used, it is usually mixed with a binder and optionally a conductive agent in a weight ratio of about 80 to 90: 5 to 15: 4 to 10. After using it as a negative electrode mixture, a predetermined pressure (usually 0.5 to 2.5
A negative electrode is produced by pressure molding at ton / cm ² ).

In the battery of the present invention, as described above, as the positive electrode active material, Li _x NiO having a higher content ratio of lithium to nickel (value of x in the composition formula) than LiNiO _2.
The feature is that _y (1.15 ≦ x ≦ 1.75, y> 0) is used. Therefore, for other members such as the non-aqueous electrolyte and the separator (when the liquid electrolyte is used), it is possible to use various materials that have been practically used or proposed for the conventional non-aqueous electrolyte battery. ..

[0012]

In the battery of the present invention, a lithium-nickel composite oxide having a low lithium content in the production range, which is a small by-product content, is used as the positive electrode active material. The amount released is larger than that of LiNiO ₂ containing a large amount of by-products.

[0013]

EXAMPLES The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to the following examples, and various modifications can be made without departing from the scope of the invention. Is possible.

Example 1 [Preparation of Positive Electrode] Lithium hydroxide and nickel hydroxide were mixed with
After mixing at a molar ratio of 1.15: 1, heat treatment was performed at 600 ° C. for 20 hours to obtain a lithium-nickel composite oxide.
As a result of composition analysis of this lithium-nickel composite oxide by ICP emission method, the atomic ratio of Li to Ni was 1.15:
It was 1. Next, this lithium-nickel composite oxide was mixed with acetylene black as a conductive agent and fluororesin powder as a binder in a weight ratio of 90: 6: 4 to obtain a positive electrode mixture. The positive electrode mixture thus obtained was pressure-molded at a pressure of 2 ton / cm ^{2 into} a disk shape having a diameter of 20 mm, and the obtained molded product was formed into a stainless mesh disk as a current collector. It was rolled and heat-treated under vacuum at 250 ° C. for 2 hours to produce a positive electrode.

[Production of Negative Electrode] A disk-shaped negative electrode made of lithium metal having a diameter of 20 mm was produced by rolling and punching.

[Preparation of Non-Aqueous Electrolyte] Lithium perchlorate (LiClO ₄ ) was dissolved in a mixed solvent of propylene carbonate and 1,2-dimethoxyethane in a volume ratio of 1: 1 at 1 mol / liter to carry out non-aqueous electrolysis. A liquid was prepared.

[Preparation of Non-Aqueous Electrolyte Battery] A flat non-aqueous electrolyte battery BA1 according to the present invention (battery size is a diameter is used by using the positive and negative electrodes, non-aqueous electrolyte solution, positive electrode can, negative electrode can, etc. : 24 mm, thickness: 3 mm).
As the separator, a microporous thin film made of polypropylene was used, which was impregnated with the above-mentioned non-aqueous electrolyte solution.

FIG. 1 is a cross-sectional view of the manufactured battery BA1. The battery BA1 shown in the drawing is a positive electrode 1, a negative electrode 2, a separator 3, a positive electrode can 4, a negative electrode can 5, a positive electrode current collector 6, and a negative electrode current collector. It comprises a body 7 and an insulating packing 8 made of polypropylene. The positive electrode 1 and the negative electrode 2 are housed in a battery case formed by positive and negative bipolar cans 4 and 5 that face each other with a separator 3 in between, and the positive electrode 1 is in the positive electrode can 4 via a positive electrode current collector 6.
Further, the negative electrode 2 is connected to the negative electrode can 5 via the negative electrode current collector 7, and the chemical energy generated inside the battery BA1 is transferred to the positive electrode can 4.
Also, both terminals of the negative electrode can 5 can be taken out as electric energy to the outside.

(Examples 2 to 8) The mixed mole number of lithium hydroxide to 1 mole of nickel hydroxide was 1.
2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.7
Inventive batteries BA2 to B using seven kinds of positive electrode active materials having different compositions in the same manner as in Example 1 except that 5 was used.
A8 was produced.

(Comparative Examples 1 to 5) The mixing mole number of lithium hydroxide to 1 mole of nickel hydroxide was 1.
0, 1.05, 1.1. Comparative batteries BC1 to BC5 using five kinds of positive electrode active materials having different compositions were prepared in the same manner as in Example 1 except that 1.8, 1.9 was used instead.

Battery BA1 of the present invention produced in Examples 1 to 8
-BA8 and the comparative batteries BC1-made in Comparative Examples 1-5
Regarding BC5, when the battery was charged to 4.3 V at a charging current of 1 mA and then discharged to 2.0 V at a discharging current of 3 mA,
The discharge capacity of each battery was examined. The results are shown in Figure 2.

In FIG. 2, the vertical axis represents the discharge capacity (mAh / g) per gram of the positive electrode active material of the positive electrode, and the horizontal axis represents the composition formula Li _x NiO of the lithium-nickel composite oxide used as the positive electrode active material. It is a graph expressed as the value of x in _y .

From the graph, the value of x is 1.15 to 1.7.
The lithium-nickel composite oxide of 5 has a value of x outside this range,
The discharge capacity per unit weight is 150 mAh / g or more,
It turns out to be big.

In the above embodiment, a specific example in which the present invention is applied to a flat battery is explained, but the shape of the battery is not particularly limited, and the present invention has various shapes such as a cylindrical shape and a square shape. It is applicable to non-aqueous electrolyte batteries.

[0025]

In the battery of the present invention, a positive electrode using a lithium-nickel composite oxide containing a small amount of by-products as an active material is used.
The present invention has excellent unique effects such as a larger battery capacity than a battery using iO ₂ as a positive electrode active material.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a flat type non-aqueous electrolyte battery according to the present invention.

FIG. 2 is a graph showing the relationship between the discharge capacity and the value of x in the composition formula Li _x NiO _y .

[Explanation of symbols]

 BA1 Flat type non-aqueous electrolyte battery 1 Positive electrode 2 Negative electrode

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Noma 2-18 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd. (72) Inventor Hiroshi Kurokawa 2-18 Keiyo Hondori, Moriguchi City, Osaka Sanyo (72) Inventor Mayumi Uehara 2-18 Keihan Hon-dori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (2)

[Claims] 1. A negative electrode containing lithium metal or a substance capable of occluding and releasing lithium as a main material, and a composition formula Li _X NiO _y.
A non-aqueous electrolyte battery comprising a positive electrode having a compound represented by (1.15 ≦ x ≦ 1.75, y> 0) as an active material. 2. The non-aqueous electrolyte battery according to claim 1, wherein the compound is obtained by heating a mixture of a lithium compound and a nickel compound at 450 to 900 ° C.