JPS60249247A - Battery - Google Patents

Abstract

PURPOSE:To provide a battery which has excellent cycle life and in which no liquid leakage or bursting occurs by using a negative electrode base composed of at least one compound selected from among tungsten oxide, tantalum oxide and titanium oxide. CONSTITUTION:A negative electrode is prepared from an electrode base composed of at least one compound selected from among tungsten oxide, tantalum oxide and titanium oxide. These oxides of transition metals are used in the form of a film prepared by electrochemically subjecting the metal to anodic oxidation. A battery is assembled by using the negative electrode, a positive electrode made of carbon and organic electrolyte. In this battery, only slight capacity decrease is caused by repeated charging and discharging and no damage such as liquid leakage or bursting occurs. Therefore this battery has high quality.

Description

[Detailed description of the invention] Industrial applications The present invention relates to negative electrode materials for batteries.

Conventional configuration and problems Batteries that use an aprotic organic solvent with lithium salt dissolved in the electrolyte and lithium as the negative electrode have a high output energy per unit weight, and are known as high energy density batteries. ing.

Currently, (CF)n1Mn02. Aq2Cr
Batteries with an open circuit voltage of approximately 3 V using O4゜SO2, S■12, etc., or CuO9CuS, B12Pb2O,
, Bi2O3, etc., as a positive electrode active material and have an open circuit voltage of about 1.6V, which has been put into practical use.

Generally, this type of battery is a primary battery, and it is expected that these high-energy density batteries can be used as secondary batteries, but there are many problems in practical application, and research is needed to solve them. It has been widely practiced. A major problem in developing this type of secondary battery is the selection of negative electrode material. Lithium has conventionally been used as the negative electrode active material, but dendritic precipitation of lithium during charging has caused a reduction in charge-discharge cycle life.

As a solution to this problem, the negative electrode is made of AI, Au, Cd, M.
g, Pd.

Lithium alloys, in which lithium is inserted into metals such as Pt, Sn, Zn, and Si, are used, but gas generation occurs due to the decomposition of the organic electrolyte during charging, resulting in battery leakage, rupture, and cycling. It had problems such as shortened lifespan. Recently, negative electrodes that utilize a topochemical reaction between oxides of transition metals such as tungsten and titanium and lithium have been considered. Since these oxides originally have low conductivity, the oxides were mixed with conductive powder such as carbon and fluorine resin powder as a binder, and the mixture was pressed under pressure to form a negative electrode. As a result, gas is generated due to the decomposition of the organic electrolyte on the carbon contained in the electrode during charging [e.g.
Kumagai, Tanno "Electrochemistry'" 49°599 (1981)]
It was causing the same problem as mentioned above.

Purpose of the Invention The present invention provides a battery that has excellent cycle life, suppresses gas generation, and does not leak or explode. It is used as a negative electrode without containing the material generated, and an anodic oxide film is created on the surface of each metal. For example, for tungsten oxide, a film created by oxidizing a tungsten plate in the air is also used. Similarly, it is used as a negative electrode that does not generate gas.

DESCRIPTION OF EMBODIMENTS The present invention is characterized in that an oxide of at least one of tungsten oxide, quintal oxide, and titanium oxide is used as a negative electrode matrix. These transition metal oxides are films obtained by electrochemically anodizing the respective metals. Further, for a negative electrode using tungsten oxide as a base material, a film obtained by oxidizing tungsten in air can also be used.

11 According to the present invention, it is possible to provide a battery with excellent cycle life that does not decompose the organic electrolyte or generate gas during charging and discharging of the battery.

[Example 1] The figure shows a battery according to an example of the present invention. 1 is a positive electrode side case, and 3 is a positive electrode prepared by mixing graphite carbon with a specific surface area of 300 m2/y and fluororesin at a weight ratio of 1:1 and press-molding the mixture on a high chrome stainless steel current collector 2. 4 is a separator made of polyethylene nonwoven fabric impregnated with an organic electrolyte (a propylene carbonate solution containing 1M L ICIO4), 6 is a negative electrode, and an anodic oxide film (tungsten oxide) 6 is formed on a tungsten plate by electrolytic oxidation, This was intercalated with Li.

The anodic oxide film was created by applying a DC voltage of 75 V to a platinum counter electrode for 10 minutes on a tungsten plate in a 3M sulfuric acid aqueous solution. The prepared electrode was thoroughly washed with distilled water, dried, and then short-circuited with lithium (Ll) in an organic electrolyte and left for one week to intercalate 6 A-' of Li. At this time, the surface turned dark blue, and it was confirmed that lithium tank stainless bronze had been formed. This negative electrode was removed from the electrolytic solution, combined with the above-described positive electrode and separator, and placed in a negative electrode case 8 and sealed with a gasket 7 to form a battery.

[Comparative example]

The following conventional example was created for comparison.

1 = tungsten oxide powder and graphite as negative electrode
The mixture was mixed at a weight ratio of 1:1, pressure-molded onto a current collector, and short-circuited with Li metal in an organic electrolyte for one week to intercalate Li. At this time, a large amount of gas was generated from above the negative electrode. Other than that, the battery was configured in the same manner as in Example 1.

[Example 2] Anodized film (tantalum oxide) on a tantalum plate as a negative electrode
A battery was constructed in the same manner as in Example 1, except that the oxide film was intercalated with Li as in Example 1.

[Example 3] A battery was constructed in the same manner as in Example 1, except that an anodic oxide film (titanium oxide) was formed on a titanium plate as a negative electrode and an intercalated Li was used.

[Example 4] A battery was constructed in the same manner as in Example 1, except that a film obtained by oxidizing a tungsten plate in air and intercalating Li was used as the negative electrode. The negative electrode is made by oxidizing the tungsten plate in air at 750"C for 3 minutes to form an oxide film on the surface of the tungsten plate. One side of the formed oxide film is partially oxidized to make electrical contact with the negative electrode case. It was peeled off, and further, this was short-circuited with Li in an organic electrolyte and left for one week to intercalate Li to form a battery negative electrode.

[Example 6] A battery was constructed in the same manner as in Example 1 except that gamma-butyrolactone containing IMLICIO4 was used as the organic electrolyte.

[Example 6] Carbon material used for the positive electrode has a specific surface area of 1000~
A battery was constructed in the same manner as in Example 1 except that 1500 m2/y of furnace carbon was used.

The table shows the open circuit voltage, discharge capacity, current density of 10/IA/7, degree of capacity decrease when repeatedly charged and discharged at depth of discharge of 76, and leakage/rupture for the batteries of Comparative Examples and Examples 1 to 6. This shows the presence or absence of.

Table: Performance of the batteries of Comparative Examples and Examples 1 to 6 9 - As is clear from the table, due to repeated charging and discharging, the capacity of the batteries of Comparative Examples decreased significantly by 80 cm after 60 cycles.
At this time, liquid leakage was observed from the gasket, whereas the batteries of Examples 1 to 6 showed very little loss of capacity due to repeated charging and discharging, and no damage such as liquid leakage or bursting was observed, indicating excellent performance. It was found that the

Effects of the Invention As described above, according to the present invention, it is possible to provide a battery having an excellent cycle life and having high commercial value without leakage or rupture.

[Brief explanation of drawings]

The figure is a cross-sectional view of a battery according to an embodiment of the present invention.
...Carbon positive electrode, 6...Negative electrode metal, 6...
... Negative metal oxide, 4... Nanakurator containing organic electrolyte 〇

Claims (1)

[Claims] (1) The constituent elements are a negative electrode, a positive electrode made of carbon, and an organic electrolyte, and the negative electrode is tungsten oxide. A battery characterized in that at least one selected from tantalum oxide and titanium oxide is used as an electrode matrix. ? ) Tungsten oxide, tantalum oxide, titanium oxide,
2. The battery according to claim 1, wherein the anodic oxide films are tungsten, tantalum, and titanium, respectively. (3) The battery according to claim 1, wherein the tungsten oxide is a film produced by oxidizing a tungsten plate in the air. (4) The organic electrolyte uses lithium perchlorate as the supporting electrolyte and propylene carbonate as the organic solvent. The battery according to claim 1, 2, 2', or 3, characterized in that at least one of gamma-butyrolactone is used.