JPH0828238B2 - Non-aqueous secondary battery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a capacity-controlled non-aqueous secondary battery using a negative electrode, and reversibly using an alkali metal such as lithium or potassium, an alkaline earth metal, a rare earth metal or a transition metal in the negative electrode. The present invention relates to a non-aqueous secondary battery using a carbonaceous material capable of intercalating and deintercalating.

<Prior Art> With the miniaturization and weight reduction of electronic devices, secondary batteries with high energy density using light metals such as lithium and potassium have been attracting attention. For the negative electrode of these secondary batteries, a simple substance of light metal such as lithium or potassium, lithium-
A light metal alloy using a low melting point alloy such as an aluminum alloy or a wood alloy, or a material containing carbon as a main component such as a conductive polymer or a heat-baked carbon body is used, and the other positive electrode is made of vanadium pentoxide or dioxide. Metal oxides such as manganese, chalcogen compounds such as titanium dioxide and titanium selenide, or organic polymers are used. In the conventional non-aqueous secondary battery system as shown here, the capacity of the negative electrode is small and the depth of discharge is limited, so that the material used for the positive electrode is greatly restricted.

The reason for this is that when light metals such as lithium and potassium are used as electrodes, the metal dendrites that cause internal short circuit of the battery are generated as a result of the metal dissolution / precipitation process due to frequent charging / discharging, When a lithium-aluminum alloy is used as the electrode, the lithium concentration in the alloy decreases due to discharge, causing embrittlement of the alloy electrode that causes a decrease in capacity, and when using a low melting point alloy such as a wood alloy, the potential In other words, the melting of alloy components that cause deterioration of characteristics occurs in an over-discharged state that makes the temperature extremely noble. That is, if these negative electrodes are discharged to a deeper depth of discharge such as complete discharge, the electrodes will suffer some trouble, and the battery performance will be adversely affected. It has been necessary to reduce the burden on the negative electrode by using the active material that does not affect the characteristics at all so that the discharge capacity is controlled by the positive electrode.

Further, by using a conventional material containing carbon as a main component such as a conductive polymer that is relatively difficult to deteriorate even in a deep discharge depth state and controlling the discharge termination condition,
Although a negative electrode-dominated battery can be made possible, these structures have a low discharge capacity and cannot be made to have a high energy density.

<Object of the Invention> The present invention enables the realization of a high-capacity secondary battery in which the discharge capacity can be the negative electrode dominant by using an electrode structure that does not affect the characteristics even if discharged to a deep discharge depth of the negative electrode. It is an object of the present invention to provide a battery having a wide range as a non-aqueous secondary battery system by making it possible to use a material which has been difficult to use as a positive electrode for a non-aqueous secondary battery in the past.

<Summary of the Invention> In view of various problems caused by conventional techniques, as a result of intensive studies, a carbonaceous material obtained by a vapor deposition method by thermal decomposition using a hydrocarbon or a hydrocarbon compound as a starting material It was found that the electrode deposited on the conductive substrate that has a catalytic action for the graphitization of TiO2 has a high capacity as an electrode material for batteries and has no effect on the characteristics even when discharged to a deep discharge depth. .

Carbonaceous materials include benzene, naphthalene, anthracene, hexamethylenebenzene, 1,2-dibromoethylene, 2
-Various transports such as butane, acetylene, biphenyl, diphenylacetylene and other hydrocarbons or hydrocarbon compounds having other characteristic groups added or substituted, using hydrogen and / or argon gas as carrier gas such as bubbler method, evaporation method and sublimation method. It is vaporized by the method and supplied to the reaction system, and 1500 ° C in the reaction system.
It can be obtained by directly forming on a metal substrate having a catalytic action, such as nickel, by the following vapor phase deposition method by low temperature pyrolysis. Here, the concentration and temperature for low-temperature pyrolysis differ depending on the hydrocarbon or hydrocarbon compound material used as the starting material, but are usually controlled at a concentration of several millimole percent and a temperature of about 1000 ° C.

The battery of the present invention uses, as a negative electrode, a carbonaceous material obtained by the vapor deposition method by low temperature pyrolysis described above deposited on a conductive substrate having a catalytic action for graphitization of carbon, and a positive electrode. And an ion conductive material.

For the positive electrode, vanadium oxide, niobium pentoxide, bismuth trioxide, antimony trioxide, chromium oxide, molybdenum trioxide, tungsten trioxide, selenium dioxide, tellurium dioxide, manganese dioxide, iron sesquioxide, nickel trioxide, Oxides of nickel oxide, cobalt trioxide, cobalt oxide, etc. or titanium sulfide, zirconium sulfide, hafnium sulfide, tantalum sulfide, molybdenum sulfide, tungsten sulfide, titanium selenide, zirconium selenide, hafnium selenide, vanadium selenide, selenide A single compound such as a chalcogen compound such as niobium, tantalum selenide, molybdenum selenide, or tungsten selenide, or a composite or mixture of two or more kinds is used. Also, a small amount of dopant may be added to these compounds. The crystalline state of the positive electrode active material is single crystal, microcrystal,
Any of the amorphous states may be present and these may coexist. The form of the positive electrode may be any of a film form, a thin film form, a sintered body, a paste form, a granular form, a highly porous body, a gel form, an ingot and the like, or a mixture thereof.

The ion conductive substance is an ion capable of electrochemically and reversibly intercalating or deintercalating an anode carbonaceous material or a salt composed of the ion and a substance capable of stably existing them. Examples thereof include electrolyte solutions such as non-brotonic organic solvent solutions, solid electrolytes, and molten salts. A separator for preventing contact between the positive electrode and the negative electrode may be arranged between the positive electrode and the negative electrode.

<Effects of the Invention> An electrode made of a carbonaceous material obtained by a vapor deposition method by low temperature pyrolysis of a hydrocarbon or a hydrocarbon compound on a conductive electrode substrate having a catalytic action such as nickel is By repeating the discharge and over-discharging, the capacity for reversible charging / discharging does not decrease, and the carbonaceous material is directly formed on the conductive electrode substrate and electrically and mechanically connected. However, since it is not necessary to add a new conductive material or a binder, the packing density of the electrode material becomes high, and as a result, an electrode having a high energy density can be obtained. Moreover, the process is simplified, and it is very effective as an electrode for a secondary battery.

A secondary battery obtained by combining a carbonaceous material deposited on a conductive substrate having the above-mentioned catalytic action as a negative electrode and a positive electrode having a reversibly chargeable / dischargeable capacity larger than that of the negative electrode is a chargeable / dischargeable battery. Since there is no reversible decrease in the chargeable / dischargeable capacity due to the number of repetitions and overdischarging, and high energy density makes it possible to obtain excellent characteristics as a secondary battery. The industrial value is extremely large.

<Example> FIG. 1 is a configuration diagram of a battery showing an example of the present invention.

A carbonaceous material obtained by directly vapor-depositing benzene as a starting material on a foamable nickel substrate by a low temperature thermal decomposition method was used for the negative electrode, Cr ₃ O ₈ was used for the positive electrode 2, and 1M perchlorine was used between both electrodes. A battery having the shape shown in FIG. 1 was produced using the separator 6 made of a polyethylene non-woven fabric containing propylene carbonate in which lithium acid was dissolved as an electrolytic solution. Here, the carbonaceous material that is the negative electrode 1 was produced using the reaction apparatus shown in FIG. That is, argon gas was supplied from an argon gas supplier 12 into a container 11 containing benzene that had been dehydrated and then subjected to distillation purification operation by vacuum transfer, and a glass tube 13 made of Pyrex was used after bubbling benzene. Benzene is fed to the quartz reaction tube 14 via the. At this time, the temperature was kept constant by heating the container 11 by the amount of heat absorbed by the evaporation of benzene, and the amount of benzene was optimized by operating the needle valves 15 and 16. The reaction tube 14 has a diameter of 15 mm made of foamed nickel.
A holder 17 on which an electrode substrate having a diameter of φ and a thickness of 1.5 mm is placed is installed. A heating furnace 18 is provided around the outer periphery of the reaction tube 14.
The temperature was maintained at 00 ° C. for about 30 minutes, the benzene supplied from the Pyrex glass tube 13 was pyrolyzed, and 39.8 mg of carbonaceous material was deposited on the electrode substrate.

The gas remaining in the reaction tube 14 after the thermal decomposition reaction is exhaust equipment.
Remove through 19,20. The electrode substrate on which the carbon body was deposited in this manner was molded by a press machine to obtain the negative electrode 1 of the battery of this example. When the capacity of this electrode was examined, the capacity capable of reversible charging / discharging was 12.5 mAh. Positive electrode 2 Cr ₃
The oxide with the composition of O ₈ is chromium trioxide in a pressure vessel.
It was obtained by heat treatment at a temperature of 0 ° C. This oxide 100
10 parts by weight of acetylene black and 5 parts by weight of polytetrafluoroethylene resin powder were added to the parts by weight and kneaded to obtain a mixture of positive electrode active materials. 100 mg of this mixture was molded at a temperature of 210 ° C. and a pressure of 300 Kg cm ^{−2 to} obtain a positive electrode 2 of the battery of this example. When the capacity of this electrode was examined, the capacity capable of reversible charging / discharging was 19.7 mAh. The capacities of the positive electrode 2 and the negative electrode 1 are those which were examined in a propylene carbonate in which 1M lithium perchlorate was dissolved in a glove box after being dried under reduced pressure at 200 ° C. for 8 hours, dehydrated.
In the battery shown in FIG. 1, the positive electrode 2 is pressure-bonded to the metallic net 5 which has been spot-welded to the positive electrode container 4 in advance, and the polypropylene separator 6 containing propylene carbonate in which 1M lithium perchlorate is dissolved is placed thereon, A negative electrode lid 3 to which the negative electrode 1 has been spot-welded in advance is covered, crimped using a crimping die, and sealed with a polypropylene packing 7, whereby a coin-shaped battery A is obtained.

Battery A was repeatedly charged and discharged with a current of 1 mA, and the change in discharge capacity with the number of repeated cycles is shown by the solid line in FIG.

Comparative Example 1 Lithium metal was used for the negative electrode, the same positive electrode as the above-mentioned example was used for the positive electrode, a metal net for current collection was provided on the negative electrode lid, and the other conditions were the same as in the above-mentioned example. B
Was produced. The reversible charge / discharge capacity of the positive electrode of Battery B was 15.0 mAh, and the theoretical discharge capacity of the negative electrode was 300 mAh. Battery B was repeatedly charged and discharged with a current of 1 mA, and the change in discharge capacity with respect to the number of repeated cycles is shown by the broken line in FIG.

<Comparative Example 2> A battery similar to Comparative Example 1 except that lithium metal is used for the negative electrode, the same material as that of the above-described example is used for the positive electrode, and the ratios of the reversible charge / discharge capacities of the positive electrode and the negative electrode are different. C was produced. The chargeable / dischargeable capacity of the positive electrode of battery C is 15.0 mA.
The theoretical discharge capacity of the negative electrode was 12.0 mAh. When battery C was repeatedly charged and discharged with a current of 1 mA, it was initially 9.5
A discharge capacity of mAh was obtained, but the discharge capacity at the 3rd cycle was 0.
It was mAh.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a secondary battery showing one embodiment of the present invention. FIG. 2 is a block diagram of a carbonaceous material production system according to the embodiment shown in FIG. Figure 3 shows
FIG. 4 is a characteristic diagram showing the relationship between the chargeable / dischargeable capacities of batteries A and B and the number of cycles. 1 ... Negative electrode, 2 ... Positive electrode, 3 ... Negative electrode lid, 4 ... Positive electrode container, 5 ... Metal net, 6 ... Separator, 7 ... Packing, 11 ... Bubble container, 12 ... Argon gas Supply system, 13 …… Pyrex glass tube, 14 …… Reaction tube, 15,1
6 ... Needle valve, 17 ... Sample holder, 18 ... Heating furnace, 19, 20 ... Exhaust equipment.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideaki Tanaka 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Inventor Takehito 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within the company (72) Inventor Sansei Kasahara 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Inside the company Sharp (72) Yoshikazu Yoshimoto 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka (72) Inventor Tomonari Suzuki 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Prefecture Sharp Corporation (72) Inventor Hiroshi Wada 22-22, Nagaike-cho, Abeno-ku, Osaka City, Osaka Prefecture (72) ) Inventor Masaru Yoshida 22-22 Nagaike-cho, Abeno-ku, Osaka City, Osaka Prefecture Sharp Corporation (72) Inventor Shigeo Nakajima, Mayor, Abeno-ku, Osaka City, Osaka Prefecture Town No. 22-22, Sharp Co., Ltd. (56) Reference JP-A-60-36315 (JP, A) JP-A-61-7567 (JP, A) JP-A-58-189968 (JP, A) JP-A Sho-60-54999 (JP, A) JP-A-59-18578 (JP, A)

Claims (2)

[Claims] 1. A non-aqueous secondary battery in which the capacity of the positive electrode capable of reversibly charging / discharging is larger than the capacity of the negative electrode capable of charging / discharging reversibly has a catalytic action for graphitization of carbon. On a metal substrate,
A non-aqueous electrode characterized by using as a negative electrode a carbon body electrode on which a pyrolytic carbon that reversibly intercalates or deintercalates an alkali metal, an alkaline earth metal, a rare earth metal or a transition metal is directly formed. Next battery. 2. The non-aqueous secondary battery according to claim 1, wherein the metal substrate having a catalytic action for graphitization of carbon is nickel.