DE2022519A1 - Electrically conductive solid electrolyte film - Google Patents

Description

Applicant i Uni can Security System Ltd ..

Electrically conductive solid electrolyte film

The present invention "relates to an electrically conductive one solid electrolyte film.

The electrolyte is a vital component in electrolytic arrangements. At the same time, however, it causes a breakdown of the cell components and a reduction in the life expectancy of the cell. Aqueous solutions or separators with aqueous electrolyte solutions in them are used with great advantage in batteries such as lead acid, nickel-cadmium, mercury-zinc and in silver coulometers. Sealing tightly closed or unsealed cases is a problem. The evaporation causes difficulties in maintenance. Aqueous solutions attack the electrodes and thereby reduce the capacity and shorten the shelf life when wet. A solution that would overcome many of the aforementioned difficulties has long been sought. Recently, developments have been made towards the production of superior electrolytes in the form of electrolytically conductive solids. The main efforts in this regard extend to structural changes of AgJ and have borne fruit in the synthesis of Ag ₅ SJ and RbAg ₄ J ₅ as well as of other highly conductive double eels such as Ag ₂ S-Ag ₂ HgJ ₄ (B _- . Reuter and K. Hardel , Natural Sciences 48, 161 (1961), T. Takahashi

. 00 9847/126 2 "~~"

and O. Yammamoto, EIeetroehem. Aeta 11, 779 (1966) and T .N. Bradley and P.D. Greene, Trans. Faraday Soc. 62, 2069 (1966). The greater part of the electrolytic transport carried out by silver ions. It is assumed that these migrate through the atomic lattice. The silver comes from a silver anode that converts Ag to Ag +, the migrates through the grid and at the cathode with reduced iodine or an iodine complex contained in this or with other cathodes such as bromine-carbon reacts.

These substances have a high electrolytic conductivity

Jk JL AA

cm ".

- 1 - 1 - 1

in the range of about 0.001 ohm cm Ms about 0.5 ohm These products are usually made in powdered form and pressed under pressure to make hard, solid disks to manufacture. An exception to this is the flexible electro lytic cell, which is characterized by an anode, a cathode and a film of a solid electrolytic Electrolytes, and which is described in the simultaneously filed patent application P

(Patent No.), our file number T 47 229- In this one Patent applications are flexible electrolytic cells and electrochemical timers.

Compared to the conventional systems have solid electrolytic Materials many advantages. This includes the elimination of water from the electrolytic system, the long-term working stability, the long shelf life, the Avoidance of the development of gases and the completely hermetic sealability.

However, there are also disadvantages as a result of the inorganic Nature of the solid electrolytes described above occur. The plates or compacts made from it are hard and stiff and therefore more sensitive to impact than a flexible system. Because of its rigidity, there are serious ones Limitations on the size of such solid electrolytes. In addition, there are rigid __ ^ _

WMTTTiTFT

Bodies have far greater restrictions on thinness than with a flexible Ulm. Therefore such "known solid electrolytic assemblies are much heavier and be larger than is often optimally desired. Ultimately there are serious limitations on such strong rigid materials that the outer outline forme η there is no freedom.

The present invention therefore relates to an arrangement many of the difficulties described above with the applicability of solid electrolytes attenuates or circumvents »The present invention provides an electrically conductive solid electrolyte film which thereby is characterized by the fact that it is largely made up of a solid Electrolyte and to a lesser extent consists of a film-forming component, laughing a preferred embodiment such a solid electrolyte is an inorganic one containing silver Metal complex, and the film-forming component contains a plasticizer.

Accordingly, for example, a solid electrolyte such as Ag-zSJ is ground, for example to 325 Tyler mesh or even finer, and is then combined with a preferably small amount of a mixture of a film former such as polyvinylidene chloride, suspended or dissolved in a solvent such as cyclohexanone. To impart suitable film properties to the film, plasticizers can also be added such as the commercially available Emery Plastolein 970 Polymeric, which is a polypropylene polyazelate having a molecular weight in the range of about 850 to about 6000, or beeswax. The film is then cast from the solution . Surprisingly, the film nevertheless is electrolytically conductive in the presence of a film former with Ag + ions by the F was found,.. -I "" be transported This is far zv for such ~ ■ s not ammengesetzt material known that a SilbeiitoEip salt, for example of the type mentioned above, and contains a film former.

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"'- ~ 00 9.847 / 12 6 2' ~~~

BATH ORIGINAL

It should be noted that the Ag + ion transport through The composite film shows that the mechanism of ion transport through the film electrolyte is essential is the same as "with completely inorganic plates of the above-mentioned flat kind. A typical galvanic element, in which such a plate or film electrolyte can be used is a silver anode / solid electrolyte plate or solid electrolyte film / iodine-carbon cathode element. It should be noted that other cathodes such as RbJ ^ or other iodine complexes can also be used. The cathode can also be used in the form of a film in which a A smaller part of a film former binds the cathode component. Various silver alloys can also be used as anodes used are like silver-gold.

Further inorganic silver-containing solid complex electrolyte materials which can be used in an advantageous manner according to the invention are, for example, Ag ^ SJ, RbAg ^ J ^ and Ag ₂ S-Ag ₂ HgJ ₄ . Further suitable solid electrolyte materials which can be used are, for example, Ag ₂ Se-HgJgAg ₂ Te-AgJHgJ ₂ and Cu ₃ S-Ag ₂ S. It should be noted that mixtures of different solid electrolyte materials, for example the above-mentioned products, are also used can be, for example a mixture of Ag, SJ and RbAg, J ^ ·

Various film-forming agents can be used, the amount of which is generally in the range from about 1% by weight to about 25% by weight , based on the total mixture of solid electrolyte material and film-forming agent. The remaining part of about 75 wt. $ To about 99 wt. ^ Consists of the solid electro-.yte.vfcerial. Part of the film former or the non-electro-

, / t:, 3chen material can consist of plasticizer to the Modify film properties. Such a proportion is usually in the range from about 5 to about 25 wt. # The Combination of film former and plasticizer. Examples of film formers that can be used according to the invention,

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include polyphenylene oxide, polysulfone and polyvinylidene chloride. An important property of the film former is that it does not completely "wet" and penetrate the solid electrolyte powder. Otherwise the electrolytic The conductivity of the film obtained is very low and therefore practically unsuitable.

Various solvents can be used to produce the casting mixture be used. Typical examples of such solvents are cyclohexanone and chloroform. Other solvents however, they can also be used depending on the type of film former used and the desired rate of evaporation of the solvent.

The thickness of the solid electrolyte film, which according to the invention produced can vary within fairly wide limits. However, a range from about 0.0001 "to about 0.025 "and especially from about 0.001" to about 0.010 ".

The final electrolytic conductivity of the film will be determined by the amount and type of film former including the plasticizer and the amount and type of solid electrolyte. Experience has shown that useful specific conductivities are contained in the essentially inorganic films the above-described low proportions of film formers can be achieved. Characteristic specific electrical

—2 lytic conductivities are in the range of about 0.2 χ 10

0hm "" ¹ cm "" ¹ to about 1.8 χ 10 ~ ² 0hm " ¹ cm for Ag, SJ containing

—1 —Ί -1

Films, and in the range of about 0.2 10 0hm cm to about 1.8 χ 10 ^-1 0hm cm " ¹ for films containing RbAg ^ J ^.

The invention is further illustrated by the following examples.

example 1

18.95 g AgJ and 20.0 g Ag ₂ S were mixed thoroughly in powder form and placed in a ceramic bowl in a _g_

0 0 9 8 4 7/1 2 6 2

7022519

Mullite rotor given. In another ceramis clie bowl was given some sulfur to maintain a sulfur atmosphere. The mullite tube was sealed and for 17 hours heated to 500 C. The melted Ag ^ SJ was removed and ground with a mortar and pestle until all of the materia]} could be driven through a Tyler 325 mesh screen. 4 g of Ag-zSJ were then with 1 g of polyphenylene oxide in the form of a 20% solution of the film-forming agent in chloroform or a total amount of 5 g of the solution mixed. The mixture was spread on a glass plate between tape-wrapped film height regulators poured and smoothed with a thin steel rod. After the solvent evaporated, a darker peel became more shiny 0.003 "thick film from the glass

p
plate has been removed. A 1 cm piece of film was placed on a thin silver strip. A powdered mixture of 90% iodine and 10% carbon was placed on the other side of the film. A silver streak was placed on the iodine-carbon mixture and the entire system was clamped together. With this battery cell, a short-circuit current of 0.2-0.1 mA (milliamps) was obtained for 1 hour.

Example 2

The procedure described in Example 1 was carried out, except that the Ag ^ SJ content of the film was increased to 99% by weight became. Short-circuit currents of 0.5-0.6 mA were obtained.

Example 3

The process described in Example 1 was carried out, except that 5 ^C J> of the 20% polyphenylene oxide film-forming agent was replaced by Plastolein 970 Polymeric. The resulting film performed essentially the same as the battery cell of Example 1. However, the solid electrolyte film was more flexible and could be more easily bent without breaking.

Example 4

80 moles of i> AgI and 20 moles of # RbJ were powdered together

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mixed and heated in a closed chamber in an inert atmosphere for 1 hour to 300 ⁰ C and then allowed to cool. The solidified RbAg ₄ J ₅ , which weighed about 24.52 g, was finely ground until all of the powder could be forced through a 400 mesh sieve. 4 · !? g of RbAg ₄ J ₅ were digested in 5 g of a 10% polyvinylidene chloride solution in cyclohexanone, and the mixture obtained was cast into a paste with a thickness of 0.005 "as described in Example 1. A battery cell was then used as in Example 1 using the 0.005 "thick straw colored manufactured PiIm. A short-circuit current of 0.3 mA was thus observed for about 2 hours.

Example 5

7.0 g of Ag ₅ SJ and 3 g of RbAg ₄ J ₅ , both in powder form finer than 325 mesh, were mixed into 10 g of a 10% polyvinylidene chloride solution in cyclohexanone, and a PiIm was produced therefrom as described in Example 4. The resulting 0.003 "thick film was checked for electrical conductivity

—2. —1 —1

examined. A value of 5 × 10 0hm cm was obtained, which is considerably higher than that of a pure Ag ₅ SJ-PiIm.

Example 6

The procedure described in Example 4 was repeated with the modification that 2.5 & 10bigen of polyvinylidene chloride film-forming agent was replaced by beeswax. The PiIm obtained was more flexible than that of Example 5, and the electrical conductivity was about 0.5 x 1.0 "

-1-1
0hm cm.

Example 7

The film-making procedure described in Example 6 was repeated except _{that Ag 3} S-Ag _{2 HgJ 4 was used in} place of RbAg ₄ Ju. The PiIm obtained had an electrical conductivity of 3 × 10 " ² ohms" ¹ cm " ¹ .

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009847/126 2
BATH ORIGINAL

7079819

Example 8

The Ulm produced according to Example 1 was in an electrochemical Timekeeper used. The film is placed between two strips of sirber and the assembly is clamped together. A direct current potential of 2.3 volts is applied to the System is applied and 0.1 mA / cm is passed through until all of the anodic silver is consumed. At this moment there is a sharp increase in the applied potential. This signal indicates the silver exhaustion and is in a digital counter arrangement applied to radars Measure spurious D.O. current.

changes and modifications to those described will be apparent to those skilled in the art Invention possible without departing from the scope of protection.

Patent claims:

009847/1262

Claims (1)

2Q22519 Patent claims • 7 Electrolytically conductive solid electrolyte film, thereby marked that he was in a greater hurry a solid electrolyte and, to a lesser extent, a film-forming component. 2. electrolyte film according to claim 1, characterized in that that the electrolyte is an inorganic "solid electrolyte". 3. Electrolyte film according to claims 1-2, characterized in that that the electrolyte is an inorganic silver-containing metal complex. 4. electrolyte film according to claims 1-3, characterized in that the solid electrolyte consists of Ag ₅ SJ, Ag ₂ S-Ag ₂ HgJ ₄ and / or RbAg.Jr- consists.
4 p 5. electrolyte film according to claims 1-4, characterized in that the solid electrolyte consists of a mixture of Ag ₅ SJ and RbAg ₄ J j-. 6 electrolyte film according to claims 1-5, characterized in, that it is about $ 75- about $ 99 by weight of the solid electrolyte and about 1 to about $ 25 by weight of the film-forming Ingredient oil consists 7. Electrolyte film according to claims 1-6, characterized in that it consists of about 75 to about 99 $ of Ag ₅ SJ and about 1 to about 25 wt. $ Of the film-forming component. 8. Electrolyte film according to claims 1-6, characterized in that it consists of about 75 to about 99 $ of RbAg ₄ J ₅ and about 1 to about 25 wt. $ Of the film-forming component. 9. electrolyte film according to claims 1-8, characterized in that that the film-forming component consists of polyphenylene oxide, Polyeulfone and / or polyvinylidene chloride is made -10- 009847/1262 - ίο - Electrolyte film according to claims 1-9 »characterized in that the film-forming component is polyvinylidene chloride. 11. electrolyte film according to claim 7, characterized in that that the electrolytic conductivity of the electrolyte film _p _i _ · ι _2 in the range of about 0.2 χ 10 0hm cm Ms about 1.8 x 10 —1 —1
0hm cm. 12. Electrolyte film according to claim 8, characterized in that that the electrolytic conductivity of the electrolyte film 1 -1 -1 -1 in the range from about 0.2 χ 10 ohm cm to about 1.8 χ 10 ohm "" ¹ cm " ¹ 13. Electrochemical arrangement, characterized in that it contains a solid electrolyte film according to claims 1-12. 14. Electrically driven arrangement, characterized in that that they have the solid electrolyte film according to claims 1-12 contains. 009847/1262