DD282331A5 - RECHARGEABLE BATTERIES - Google Patents

Abstract

The invention relates to rechargeable batteries, preferably lithium batteries, which can be used as electrochemical Sekundaerstromquellen for power supply of microelectronic devices and in batteries for vehicles. The object of the invention is to develop batteries which have a high energy and charge density, so that they as electrochemical Sekundaerstromquellen a large number of cycles, d. H. long life, reach. According to the invention, the object is achieved by the electrodes for these batteries containing, in addition to additives known per se, such as acetylene resin and binders, unsubstituted or substituted polyarylenevinylenes. The advantage of the invention is that the substituted polyarylenevinylenes according to the invention remain insoluble in all redox stages in the electrolyte and an increase of the energy and charge density is achieved many times over. Sekundaerstromquelle; Lithium; organic polymer compound; substituted polyarylenevinylenes; aprotic solvent; Energy density; Charge density; Zyklisiereigenschaften}

Description

R _3: H, CN, NO _2, COOR

and R ₁ and R _{2 may be the} same or different.

3. Battery according to claim 1, characterized in that the electrode in an aprotic organic. Electrolyte is used.

4. Battery according to claims 1 and 3, characterized in that the electrolyte is lithium hexafluorophosphate in propylene carbonate.

5. Battery according to claim 1, characterized in that the electrode of polyarylenevinylene is used together with a light metal electrode.

6. Battery according to claim 5, characterized in that a lithium electrode is used.

Field of application of the invention

The invention relates to rechargeable batteries that can be used as power sources in the low-current range for powering microelectronic devices with external charge or as a buffer power source in such devices with solar cells and in the higher current range in batteries for vehicles and stationary application.

Characteristic of the known state of the art

It is known that modern rechargeable electrochemical current sources are under development, which are superior to conventional secondary batteries such as lead and nickel-cadmium storage batteries in essential parameters, in particular energy and charge density and number of cycles, and allow miniaturization for microelectronic applications. Thus, a wide variety of different, mostly conjugated '' Irganic polymers have been investigated for their utility as electrochemically active materials in lithium secondary cells. These include such polymers as polyacetylene, polypyrrole, polyaniline or poly (p-phenylene). which are generally used in the positive, but in the case of polyacetylene or poly (p-phenylene) in the negative electrode. However, essential characteristics, especially energy and charge density and the cycle life of said polymers are still insufficient, so that it is attempted to achieve better electrode properties by development and use of other organic polymer compounds. Polyarylenevinylenes appear to be promising with respect to use in the abovementioned field of application of the invention. [0006] The use of sparingly soluble nonaryl-substituted polyarylenevinylenes as active materials in electrodes for battery systems with aprotic electrolyte solutions has been demonstrated on soluble aryl-substituted polyarylenevinylenes in light-metal accumulators (DDR patent DD 230963 A1) is not known.

Object of the invention

The aim of the invention is to provide batteries with high energy and charge density and large number of cycles available, which are energy-economically favorable due to these properties.

Explanation of the essence of the invention

The invention has for its object to develop batteries high energy and charge density and large number of cycles. According to the invention, the object is achieved by sparingly soluble substituted polyarylenevinylenes of the general type 1

be used in the positive and / or negative electrodes, wherein the radicals R ,, R ₂ and R _{3 have the} following meaning:

R and R _{2 are} H, OCH ₃ , OAlkyl, CH ₃ , NR ₂ , halogen, CN

R ₃ is H, CN, NO _2, COOR

and R | and R _{2 may be the} same or different.

For example, poly (2,5-dinethoxy-1,4-phenylenevinylene) 2

CH = CH-

Poly (2,5-dimethoxy-1-phenylene-cyanovinylene-i, 4-phenylene-1-cyanovinylene) 3

C = CH-

and poly (2,5-dimethoxy-1,4-phenylene-2-cyano-vinylene-2,5-dimethoxy-1,4-phenylene-1-cyanovinylene) 4

OCH

C = CH I

CN OCH ₃ CN

are used as substituted type 1 polyarylenevinylenes.

Surprisingly, it has been found that the sparingly soluble substituted polyarylenevinylenes according to the invention in: Redοη redox stages, even irr. highly oxidized state, remain sparingly soluble in the electrolyte, resulting in the advantage of extremely low Selbstentladerate results. Furthermore, the electrode contains additives which should lead to an improvement of the conductivity and porosity, for example carbon black, and optionally a binder for increasing the mechanical stability. Thus, the electrode compositions according to the invention are particularly well suited for example for secondary cells with light metal electrodes, preferably lithium, and aprotic organic electrolytes, the known organic compounds being the known compounds, for example propylene carbonate with and without additives, in conjunction with also known conductive salts such as lithium hexafluoropiophosphate, Lithium hexafluoroarsenate, u. a. to be used. Surprisingly, when using lithium hexafluorophosphate in propylene carbonate as the electrolyte, a substantial increase in the energy and charge density of the light metal battery with the electrode according to the invention was observed by a multiple over other electrolytes, and the positive effect of this electrolyte was also observed if both electrodes consisted of a polyarylenevinylene.

embodiments

example 1

The positive electrode is prepared by adding 20 mg of poly (2,5-dimethoxy-1,4-phenylene-2-cyanovinylene-1,4-phenylene-1-cyanovinylene) with the same amount of hydrophobized carbon black (35 parts by weight Teflon, 65 parts by weight Acetylene black) and homogenized. From this mixture entsprethende amounts with about 40kN / electrode on a nickel mesh (diameter: 5 mm) pressed or pressed. The negative electrode is made by forcing a lithium disk into a nickel mesh. Both electrodes are immersed in a one-molar solution of LiPF ₆ in propylene carbonate as the electrolyte. More than 12 cycles were achieved using a current density of 50 microamps per square centimeter with a voltage limitation between 1.0 and 4.0V.

Example 2

The electrode material of the positive electrode is prepared by adding 150 mg of poly (2,5-dimethoxy-1,4-phenylene-2-cyanovinylene-M-phenylene-i-cyanovinylene) with the same amount of hydrophobized carbon black (35 parts by weight of teflon, 65 parts by weight of acetylene black). be homogenized.

The resulting mixture is pressed with the aid of a corresponding Pre.'öwerkzeuges into tablets with a diameter of 16 mm and a tablet height of 0.8 mm.

In this case, a pressing pressure of 60kN / tablet is applied at a pressing time of 2 min.

The negative electrode is made by punching out a lithium disk of the same diameter. Both electrodes are housed in a stainless steel housing and mechanically separated and electrically connected by an impregnated with a consisting of a 1 M solution of LiPF ₆ in anhydrous propylene carbonate electrolyte nonwoven fabric.

With the button cell thus produced, more than 14 cycles were achieved at a current density of 50 microamps per square centimeter and a voltage limit between 1.0 and 4.0 volts.

Claims (2)

claims: 1. rechargeable battery, gekenn .eichnet characterized in that at least one electrode in addition to known additives such as acetylene black and binder contains a sparingly soluble Poiyarylenvinylen. 2. Battery, according to claim 1, characterized in that the Polyarylenvinylen according to the general formula 1 eubstitutie.t is, = CH ι r = ' R ₃ R ₂ R- n? 3 wherein R ₁ , R ₂ and R _{3 have} the following meaning. R ₁ and R ₂ : H, OCH ₃ , OC ₂ H ₅ , CH ₃ , NR ₂ , halogen,