DD241978A1 - ELECTRODE FOR SEKUNDAERZELLE - Google Patents

Abstract

Secondary cells are used as reversible electrochemical energy storage, in particular for the power supply of microelectronic devices, such as calculators or electronic clocks. The aim of the invention is to provide reversible electrode materials with high energy density. It has been found that 1,2-dithiolo (4,3-c) 1,2-dithiols are electrode materials having the desired properties. Fig. 2

Description

Surprisingly, it has been found that 1,2-dithiolo (3,4: d) 1,2-dithiols (I) are such electrode active materials with the desired properties.

se

HAc

Advantageous for the use of these compounds as electrode active materials for rechargeable electrochemical power sources is that they are not sensitive to environmental influences. They can therefore be handled without special measures. Furthermore, these substances are neither poisonous nor aggressive.

By suitable selection of the electrolyte composition, it is possible to realize secondary cells whose electrodes are both solid and liquid. The electrochemical activity is extremely high and the corresponding cells have a high ampere-hour capacity which is practically higher than that of the polyacetylenes.

Due to the pronounced reversible redox properties of 1,2-dithiolo (4,3-c) 1,2-dithfolene, a large number of cycles can be achieved with corresponding secondary cells.

embodiments

1. The positive electrode is prepared by adding a mixture of 50% 1,2-dithiolo (4,3-c) -1,2-dithionl-3,6-dithione (1a) and 50% hydrophobizing carbon black into a nickel mesh is pressed. The counterelectrode used is a lithium disk pressed into a nickel mesh. The electrolyte consists of a mixture of dimethoxyethane / propylene carbonate (50/50) to which 1 mole per liter of lithium perchlorate has been added as the conductive salt.

Figure 1 shows a corresponding experimental cell containing the positive electrode (1), the Lihiumelektrode (2), the electrolyte (3) in a glass tube (4) with closure (5). FIG. 2 shows the discharge characteristic of the cell in the case of galvanostatic discharge with ΙΟΟμΑ / cm ² , wherein the weighed amount of the positive electrode active material is 4 mg. Figure 3 illustrates the behavior in the cyclization of the cell with constant current.

2. 1 mg of 1,2-dithiolo (4,3-c) -1,2-dithiol-3,6-dithione (1a) are dissolved in about 1.5 ml of dimethoxyethane. As the counter electrode, a lithium electrode according to Example 1 is used. The positive electrode is a nickel mesh with impregnated hydrophobized carbon black. FIG. 4 shows the discharge characteristic curve with galvanostatic load with ΙΟΟμΑ / cm ² .

3. 3 mg of IC are mixed with 3 mg of hydrophobized carbon black and pressed into a nickel mesh. The counter electrode is again a lithium electrode of the type mentioned above.

FIG. 5 shows the discharge with ΙΟΟμΑ / cm ² . The Ruhezellenspännung is 2.7V.

The electrolyte used is a 1 molar solution of lithium perchlorate in propylene carbonate / dimethoxyethane (50:50).

Claims (3)

-1- 241973 Invention claim: 1. electrode for secondary cell, characterized in that it contains, in addition to additives, such as acetylene black and binders, as active material 1,2-dithiolo (4,3-c) 1,2-dithiols of the general formula I. where X = S, Se, NAc (AC = acyl group of an organic acid)
mean.- 2. Electrodeforsecondary cell according to item 1, characterized in that the active material I is in liquid and / or solid form. 3. electrode for secondary cell according to item 1 and 2, characterized in that mixtures of different compounds of general formula I are present as active materials. For this 3 pages drawings Field of application of the invention Secondary cells have a wide range of applications as reversible electrochemical energy storage. In particular, microelectronics, through the development of mobile devices such as calculators, electronic clocks or pacemakers, require durable power sources that can be recharged by other, sometimes intermittent, energy sources. Characteristic of the known technical solutions In addition to conventional secondary power sources such as the lead-acid battery, alternative current sources which have a high energy density and can be realized in miniature design are increasingly being described recently. Polyacetylene in particular has gained increasing interest in recent years, since electrodes can be produced from this material which meet the above-mentioned requirements. However, the technical use of a working on the basis of polyacetylene secondary element is still pending and will not be realized in the near future, since some crucial disadvantages of a practical application preclude. This relates in particular to the high sensitivity of polyacetylene to atmospheric oxygen and moisture. This makes the handling of the substance difficult and is only possible in highly specialized equipment. Another disadvantage is the large self-discharge rate of current sources, which is caused in particular by the resulting in the course of the electrochemical process negatively charged form of the polyacetylenes. Furthermore, a chemical decomposition of the electrode active material in the cell occurs over time so that it would be limited in its life and possible number of cycles. Object of the invention The aim of the invention is to provide reversible electrode materials which have a high energy density, are chemically stable, resistant to environmental influences and are not toxic or aggressive. Explanation of the essence of the invention The object of the invention is to provide reversibly operating electrode materials which have a high energy density, are easy to handle and enable a long service life of corresponding secondary cells.