DE2126055C3 - Primary element with a negative lithium electrode, a solid lithium iodide eltrolyte and an iodine-containing, electrically conductive positive electrode - Google Patents

Description

Such a primary element is known from US Pat. No. 3,455,742, in which solid cells are described that have a lithium anode (anode = negative electrode), however a metal-metal halide cathode (cathode = positive Electrode) is provided; It is mentioned in this USA patent that the cathode also consists of Iodine can consist. In column 3 it is further stated that such a cell is based on the present this corrosive metal is not acceptable in its mode of action, it is also stated that with a Cells working with iodine-carbon cathodes only have a low energy density.

The USA patents 3 352 720 and 3 057 760 can now admittedly use electrically conductive charge transfer complexes, consisting of an organic donor component and iodine are taken as components for the positive electrodes, essential however, it is here that these two U SA patents relate to cells with liquid electrolytes and wherein the anodes made of zinc, cadmium, magnesium, aluminum, etc., belong to groups II and III, respectively Have metals. The cells described in these U.S. Patents 3,352,720 and 3,057,760 have electrolytes based on an aqueous salt solution, i.e. electrolytes in connection with which a lithium anode cannot exist because lithium is very reactive with water. General The practical value of a cell depends to a large extent on complex reaction kinetics Conditions, d. H. on the dynamic response behavior. However, it is the factors that determine the Influence and determine reaction kinetics in solid systems very differently from those in the liquid electrolyte cells are important, so that the basic separation of those skilled in the art these two areas is also recognized.

Finally, the journal »J. of electrochem. Soc. «114, 1967, on p. 323 to 329, galvanic elements with a solid electrolyte are taken, the positive electrode of which consists of an electrically conductive charge transfer complex of an organic donor component and iodine. Various bivalent metals, such as silver, are used as anodes, with energy densities of 1 watt hour per 0.454 kg and instantaneous currents of 25 mA / cm ² from cells with a magnesium anode and an organic iodine cathode. The same authors refer to the journal »J. Electrcchem. Soc. «115, 359, from 1968, to a considerable increase in the instantaneous current that is achieved when vapors of liquids with a high dielectric constant, such as water, are allowed to access the anode / electrolyte interface.

The object of the present invention is to provide a primary element based on the solid matter principle create, which has a high output voltage with a high energy density and a long service life connects.

To achieve this object, the invention is based on the primary element mentioned at the outset, which is known Kind and consists according to the invention that the positive electrode consists of an electrically conductive Charge transfer complex consisting of an organic donor component and iodine.

Such primary elements have, depending on the cell structure and the specific cathode material an open circuit voltage between 2.7 and

3VoIt and a theoretical energy density of 213 watt hours per 0.454 kg, with energy densities up to a size of 136 watt hours per 0.454 kg have been effectively obtained during the discharge of encapsulated primary elements at room temperature.

The invention leads to stable, extremely durable primary elements with a high energy density and high battery voltage; such primary elements can in particular be used as long-life batteries be considered for relatively low power consumption ι ο.

The primary elements according to the invention thus have a negative lithium anode, a solid lithium iodide electrolyte and a positive electrode made of an electrically conductive charge transfer complex, consisting of an organic donor component and iodine, being the anode reaction works like this:

Li - Li ⁺ e
with the following cathode reaction

J ₂ + 2e ► 2J-

resulting in an overall response of ^2S

2Li + J ₂

2LiJ.

This electrochemical system is particularly advantageous in that lithium is like most electropositive metals with the lowest equivalent weight have a high energy density and that the electrolyte formed when the element is discharged is LiI, a lithium salt which contains the has the highest ionic conductivity, much higher than the ionic conductivities of divalent ones Halides.

The iodine on the cathode side is advantageously at least partially chemically bound, for example in charge transfer complexes containing organic iodine. In this respect, preferred embodiments of the new cathode material consist of a mixture of iodine and poly-2-vinylpyridine.I ₂ or poly-2-vinylquinoline I ₂ , so that charge transfer complexes result in the desired proportions, which form a putty-like, flexible, but solid mass . The electrolyte is lithium iodide, which is formed in situ by contact between the lithium anode and the cathode surfaces, the lithium reacting with the iodine in the cathode and forming a solid lithium iodide electrolyte layer in contact with the anode and cathode. According to another exemplary embodiment, the electrolyte consists of a coating of lithium iodide or another lithium halide on the lithium anode, and is formed by the reaction of the lithium with the iodine or another halide. The cathode is generally in contact with an inert cathode current collector, which is expediently made of carbon or of a metal that is inert to the cathode. Likewise, an inert metallic current collector is used to make electrical connection with the soft lithium anode.

Further refinements are the subject of the subclaims. In the following, the Figures Structure and mode of operation of exemplary embodiments of the invention explained in more detail.

It shows

F i g. 1 in an exploded perspective view the individual sub-components of a primary element according to the invention,

Fig. 2 shows the arrangement of Fig. 1 encapsulated in a potting compound,

F i g. Fig. 3 is a sectional view of another one preferred embodiment of the invention in the form of a thin cell, while

F i g. 4 in the form of a diagram of discharge profiles in the cells of FIG. 3 shows the one Lithium anode and a P2VP-5J, cathode.

The in F i g. 1 in an exploded view consists of a metallic, anode-side contact element or a current collector 2, a lithium anode 4, a cathode 6 and a cathode current collector, which consists of a metallic screen 8, which is preferably provided with a further metallic sheet or disk 10 is spot welded. The components of the cell are stacked on top of one another, after which the stack is then compressed with a suitable pressure of about 70 lcg / cm ² to form the complete cell. The anode contact element 2 has holes 12 which have been punched by a pin or some other conical punch, resulting in protruding, sharp edges which dig into the lithium anode and firmly connect the contact element to this anode. A metallic screen or a metal mesh can be used as an anodic contact element with the same advantage. The cathode material, which is suitably finely divided, is compacted when the cell is shaped into a solid disk, in which the cathode contact screen 8 is then embedded. If desired, however, the cathode material can also be pelletized or shaped into a one-piece contact body before it is assembled into a cell.

As shown in Fig. 2, the resulting cell, which is composed of a plurality of lamellar Layers are in intimate contact with one another, encapsulated in an inert potting compound 14; the inert potting compound consists preferably and in a suitable form of polyester, which serves to protect the cell against energy loss or degradation and against exposure to the atmosphere to protect.

The in F i g. The cell shown in FIG. 3 can be made in the form of a thin disk or strip which can only have a thickness of no more than 380 to 500 μ, but also any other dimension. The cell is enclosed in a plastic casing 16, which is polyvinyl chloride or a plastic the designation "Teflon" has proven to be particularly suitable; however, it can also be a potting housing Made of polyester or epoxy resin or some other hermetically sealed housing is used which is impermeable to iodine and common atmospheric constituents, d. H. impermeable to oxygen. Nitrogen and water vapor. In doing so, a thin metallic one comes across AuDdenstromsammler 18. which is expediently made of a nickel foil on the plastic casing means Vacuum deposition or electroless plating deposited nickel plate is made immediately to a thin lithium electrode 19; in Hip in

5 6

suitably achieve a thickness between 25.4 and 254 μ. The Bat exhibits a low internal resistance. It is particularly useful if the terier can be achieved that cells in Lithium is in the form of a foil, but it can be connected in series and parallel and averaged over one another Vacuum deposition, electroplating or stacking.

other common methods on the current collector 5 according to the invention. Cells are deposited by atmospheric being. The initial thin film of a spherical moisture adversely affected, so that Lithium iodide electrolyte 20 can be assembled and encapsulated in, as described above already described, when assembling the cell dry atmospheres, preferably in be preformed on the lithium surface, or dry spaces or inclusions with a rela are formed spontaneously if the pure lithium ionic humidity is less than about 2%, anode surface in contact with the cathode, being essentially anhydrous and / or brought dry will. The cathode 22 can be used from compacted components. All system powder exist, or what is essentially appropriate cell arrangements described herein and less, in the form of a paste as cathode material searches or measurement results are not encapsulated or as a testicle material and a binder, with- 15 cells were in such dry rooms or for example carried out in the form of vinyl dispersions on the dry inclusions, with even Anode applied. This new plastic cathodried air or argon atmosphere available material will preferably goods directly to the cathode.

The current collector 24 is applied, whereupon the material in the lithium cells according to the invention is then brought into contact with the anode as being suitable for use as a cathode material layer. The new plastic cathode material can also be shown to charge transfer complexes, heated and melted and made up of organic material and iodine, although any brushing or spraying can be applied, and any other cathode can also be used - it can be applied as a solution in tetrahydrofuran, which is electronically conductive and available are brought, whereupon the solvent then contains 25 iodine for the electrochemical reaction. When is evaporated. The cathodic current collector or the charge transfer complex may consist of a thin metal foil, a well-known class of materials, which or, as in the case of the anodic current collector, may contain two components, namely a metal deposited on the plastic housing one of them has an electron donor coating. It has been found that 30 and the other is an electron acceptor; The materials for the cathode collectors are weakly connected complexes, the most suitable have been shown to be zirconium, platinum or have a higher electronic conductivity than compounds of both, since they do not show any individual component. For the present invention reaction or aging, deterioration or degeneration, suitable charge transfer complexes exhibited decomposition. For a shorter battery life from an organic donor component, for example between 4 and 6 months and iodine. the electron acceptor, and have had advantages, nichrome, nickel or other highly preferred conductivity that is greater than 2.5 nickel compounds have proven to be suitable. 10 ~ ⁴ S / cm each. The charge transfer complexes fin with the anodes and cathode current collectors are in chemical equilibrium with a small amount of free iodine for connection to external circuit connections, which is connected to the electrical leads 26 and 28, which is available through a trochemical reaction. These charge openings in the plastic casing are tightly sealed and transfer complexes have a wide area. The stacked cells - electronic conductivity, is the conductivity components can be low to achieve a good, then the output current is relatively adhesion and a good contact between the 45 small, due to the high internal ohmic layers are pressed together, with only resistance. Cathodes have intimate low pressures of the order of magnitude of 1.8 kg / cm ^2. Mixtures of such a low conductivity are required if the new plastic cathode-pointing complexes with powdered graphite material is used in order to contain the adhesion between or inert metal, high conductivities are compared to the layers that are on and can be maintained during storage and discharge with regard to their effect with cells without external forces, which use complexes of high control center capability. Thus, suitable cells can be fabricated in an extraordinarily large charge transfer complex; a variety of shapes can be fabricated; for example, encapsulated, flexible cells, no thicker than 0.5 mm, 53 being used as the organic donor component, 53 are polycyclic aromatic compounds, such as have been produced so that it is possible to use batteries, e.g. B. pyrene, perylene, anthracene, naphthalene, eryin to produce almost every conceivable configuration. throsine, azulene and fluorene; Organic polymers, for example, such a battery can be wrapped around an electronic such as polyethylene, polypropylene, or polytronic circuit in order to effectively utilize the space available for styrene, polypyrrole, polyamides and polyvinyls, or nitrogen or sulfur-containing heterocyclic systems . If such flexibility is not an emergency connection, such as B. phenothiazine, phenazine, the cells can be encapsulated in rigid plastic 10-phenylphenophiozin, thianthrene, 10-methyl or can be sealed in metallic thiazine and methalyin blue, polymerized or poly containers. Larger capacities per merisable compounds, in which a hetero-electrode unit area can be achieved by increasing the cyclic nitrogen content as a side chain or sub-thickness of the anode and cathode, substituents are built in, in particular vinyl compounds, so that cells are conveniently fertilized and polymers such as poly result, which a thickness of up to 1.25 cm and more 2-vinyl-quinoline, poly-2-vinylpyridine, poly-4-vinyl

pyridine, poly-5-vinyl-2-methylpyridine and poly-N-vinylcarbazole. The proportions of iodine to organic components can be varied over a wide range, although a high proportion of non-complex iodine in the cathode generally increases the internal resistance of the cell, with the exception of the preferred new plastic cathode materials. The cathode can be produced as a compact structure or in tablet form from powdery material, but it can also be applied in the form of a paste or deposited from a solution mixed with an inert solvent. Other iodine-containing cathode, which are electrically conductive, can also be used, for example, mixtures of iodine ·. $ Coal or graphite.

In the known production of a charge transfer complex of iodine with poly-2-vinylpyridine or poly-2-vinylquinoline a molecule of J ₂ coordinated with each N-atom, which results in a solid mass with an iodine content of about 71 percent by weight in the case of poly-2 Vinylpyridine complex and of about 62 percent by weight in the case of the poly-2-vinylquinoline complex. The preferred new cathode compositions for the invention are a mixture of iodine and the solid poly-2-vinylpyridine _{I 2} or poly-2-vinylquinoline I ₂ and thus form a charge transfer complex in the desired proportions. (It appears expedient to use the formulas for the cathode materials in the further description

P2VP / iJ ₂ and P2VQ · nJ ₂

where P2VP is the poly-2-vinylpyridine and P2VQ is the poly-2-vinylquinoline and η is the number of moles of J ₂ for each atom of N. For example, the charge transfer complex with one mole of J ₂ per N atom is referred to as P2VP · J ₂ ; are 4 moles of ₂ J per N atom ^ ₀ added, then the mixture as P2VP · 5J ₂ hereinafter). At normal room temperature, this mixture is a putty-like, resilient solid mass which is sufficiently plastic to be applied to a solid base, for example a sheet of an anode metal. These materials are useful as cathodes in solid cells up to temperatures where softening results in loss of dimensional stability; this point can be between 20 and 75 ° C or higher and depends on the degree of polymerization of the organic component of the charge transfer complex. It is believed that the plastic state of the cathode material allows excellent atomic bonding of the cathode material to the anode and to the cathode current collector, resulting in greater cell outputs.

The following examples show the production of the new cathode mixtures, it being understood that any process for preparing the charge transfer complex can be used, in particular the molecular weight of the polymer Component of the complex can be modified by appropriate variations. In general particularly satisfactory cathode materials are obtained using a charge transfer complex, which has precipitated from an organic solution.

Example I.

Conventionally, poly-2-vinylquinoline is prepared by polymerizing a benzene solution of 2-vinylquinoline using an n-butyl lithium polymerization initiator, conveniently by adding 11.3 grams of the initiator (15 to 22 percent by weight in hexane) to a solution of 100 g of 2-vinylquinoline in 1500 cm ^{3 of} benzene (the solution at 45 ° C.) is added and the mixture is stirred for 10 minutes. A solution of iodine in benzene is added to the poly-2-vinylquinoline solution in excess of the stoichiometric ratio in order to _{precipitate the P2VQ · I 2} charge transfer complex. The presence of an excess of iodine can easily be determined by the red color of the mixed solutions. The precipitate is filtered, vacuum dried, and mixed with about between 1 and 17 molecular weights of I ₂ for each atomic weight of N in the complex to produce a plastic, compliant mass.

Example II

The preparation procedure for Example I is repeated with the exception that 2-vinylpyridine is used in place of the 2-vinylquinoline. The resulting material has the formula P2VP · ni ₂ , where η is between 2 and 7, and is in a plastic state. It goes without saying that solutions of poly-2-vinylquinoline and poly-2-vinylpyridine can be prepared using a variety of organic solvents or conventional catalysts, such as, for example, the solvents tuluen and hexane and the catalysts sodium metal and potassium metal. The polymers can also be prepared from aqueous solutions using catalysts such as acetyl peroxide, lauroyl peroxide, or methyl ethyl ketone peroxide with a cobalt naphthenate accelerator.

Example III

2-vinylpyridine was thermally polymerized by heating at about 80 ° C. for 8 hours. The The resulting red thermoplastic material was cooled, ground to a powder and treated with 20 up to 40 parts of iodine mixed to a plastic, pliable solid

The new compounds according to the invention are particularly useful as iodine-containing cathode materials useful because apart from their putty-like physical condition they are minor and relative have constant electronic resistance over a wide range of iodine levels and themselves have a relatively low electrical resistance with extremely high iodine contents.

With proportions between 3 and 7 mol of I ₂ per nitrogen atom (or per monomeric unit), the electrical resistance of the new cathode material is low and essentially constant. For example, the specific resistance of the

ίο

P2VP x 3 J ₂ manufactured from match 1 about 1400 ohms cm; from P2VP-4J ₂ 1000 Ohm · cm, from P2VP · 5J ₂ 1000 Ohm · cm, from P2VP · 6J ₂ 930 Ohm · cm and from P2VP · 7J ₂ 1400 Ohm · cm. If the iodine content is lower, the resistance increases rapidly, for example P 2 VP · 2J _{2 has} a specific resistance of about 40,000 ohm · cm. If the iodine content rises above about 7 mol I ₂ per monomeric unit, the resistance also increases, for example the specific resistance of P2VP-8J _{2 is} 2600 ohm · cm. In this respect, too, the new cathode materials prove to be particularly advantageous because they are able to provide a large proportion of iodine for an electrochemical reaction without the cells resisting due to the change in the cathode mixture from the consumption of iodine, greatly increased. This leads to longer-lasting cells with greater power and energy output. For batteries with a high current output, cathodes are advantageously used which contain about 6 moles of iodine per monomeric unit, since then about 4 moles of iodine are available for the reaction at the lowest resistance level. Higher proportions of iodine, up to 15 mol of iodine per monomeric unit, are advantageously used in low-current batteries, since a significantly higher energy capacity is obtained and the polarization (IR drop) is not undesirably large with low current draws.

The following examples relate to elements or batteries produced according to the invention:

Example IV

Primary elements were manufactured using a lithium anode and various electrically conductive cathodes containing iodine available for an electrochemical reaction. The cathodes were produced by mixing iodine with other powdery cathode components, graphite and / or an organic material, the mixtures being formed at a pressure of about 368 kg / cm ² to form a tablet-shaped compact with a diameter of 1.25 cm and a thickness of about 1 cm mm were compacted. The organic material used was such that it reacted spontaneously with the iodine to form a charge transfer complex. In some cases, as indicated, an organic _{I 2} charge transfer complex was prepared separately by conventional methods and then pressed into cathode tablets either alone or by admixing graphite. The cathode tablet was placed between a lithium anode of 1.23 cm ² and a collector consisting of a nickel foil, the whole thing was wrapped with a Teflon tape and held together by a clamp under slight pressure. The lithium anode disk was cut out of a lithium tape which had been cleaned and scraped in petroleum ether. The cell was examined or measured with regard to its open-circuit voltage (U ₀ ), the current output at different voltages (μΑ / V) and the short-circuit current (I _k ). The cells were then coated with varnish and measured again after 24 hours. Typical results are shown in Table 1.

table

battery Cathode mix U _n Initial measurements μΑ / V μΑ / V U ₀ Viessungen after 24 hours μΑ / V μΑ / V (Element) 1.61 0.6 / 1.54 24 / 0.04 0.49 0.19 / 0.51 20 / 0.03 No. 99% iodine, 1% coal 2.85 IJvA 1.05 / 2.85 1400 / 2.35 2.80 IJvA 0.93 / 2.40 470 / 0.75 1 95% iodine, 5% charcoal 2.90 24 1.10 / 2.90 1500 / 2.50 2.85 21 1.05 / 2.85 760 / 1.25 2 90% iodine, 10% coal 2.90 4600 1.05 / 2.75 110 / 0.20 2.80 680 1.10 / 2.80 720 / 1.15 3 50% iodine, 50% poly
ethylene
50% iodine, 50% poly 2.90 6300 1.00 / 2.80 130 / 0.20 2.85 1100 1.10 / 2.85 500 / 0.80 4th propylene 122 1450 5 47 '/ _2% iodine, 47% ¹ A poly 2.85 145 1.00 / 2.85 380 / 0.65 2.75 710 1.07 / 2.75 790 / 1.30 propylene, 5% coal 6th Pyrene 2J ₂ ¹ ) 2.95 470 1.10 / 2.95 450 / 0.80 2.95 1650 1.06 / 2.90 135 / 0.30 50% pyrene 2J ₂ ¹ ), 3.00 1.10 / 3.00 370 / 0.70 2.90 1.06 / 2.85 255 / 0.45 7th 50% iodine 630 150 8th Pyrene 2J ₂ ² ) 3.00 480 1.10 / 3.00 770 / 1.35 2 £ 5 305 1.10 / 2.95 1050 / 1.85 50% pyrene 2J ₂ ² ),
50% iodine 3.00 1.10 / 3.00 860 / 1.45 2.85 1.07 / 2.85 600 / 1.00 9 50% iodine, 50% pheno- 2.95 1600 1.07 / 2.95 680 / 1.15 2.90 3100 1.09 / 2.90 740 / 1.25 10 thiazine 2900 1100 11th 47 '/ ₂ % iodine, 2.90 1200 1.02 / 2.90 1050 / 1.85 2.85 1450 1.08 / 2.85 820 / 1.35 47V ₂ % phenotriazine ³ ), 12th 5% coal 2700 1750 2-phenothiazine 3J ₂ 2.85 1.07 / 2.85 104 / 0.20 2.85 1.09 / 2.75 93 / 0.15 Perylene · J ₂ 2.01 2.80 13th 118 102 14th 2700 3700

') Made by melting together pyrene and iodine.

² ) Produced by precipitation from a CCl ₄ solution.

³ ) Manufactured by precipitation from a benzene solution.

Other organic materials that in connection with iodine in cells with the same effect or with same success, either with or without the addition of 5 to 10% graphite, are nylon, Lucite (methacrylic resin), Lucite paste in dichloroethylene. Pyrrole, polypyrrole, naphthalene, dimethylglyoxime, Phenolphthalein, Phthalimide Erythrosine, Methylene Blue, Urea, Brominated Pyrene, Teflon and o-tolidine.

Example V

If a powdery electrical conductor, for example carbon or a powdery material to improve the conductivity of the cathode is built into the cathode, then an electrolyte film is preferably formed on the lithium anode before the cell or the element is assembled in order to reduce an internal short circuit. The electrolytic film is formed by exposing the lithium surface to dry air or argon containing atmosphere which contained a lithium reactive vapor to form a conductive lithium salt, preferably halogens J ₂ , Cl ₂ or Br ₂ , although other reactive vapors may also be used can be used, for example methanol or ethyl ether. For further explanation, the elements produced according to Example I had a cathode made of 47 ₁ /2% pyrene · 2I ₂ , 47V ₂ % iodine and 5% powdered carbon; one element had a clean lithium anode and a second cell had a lithium anode coated with a LiJ film. Tests carried out in accordance with measurements in Example I gave the following results:

Table 2

anode

Li

Li coated with LiJ ..

2.20
3.10

3200
3500

24-hour measurement

2.70
3.00

1000

Example VI

There were ό cells with a diameter of 11.25 cm and a thickness of 0.55 cm in one mood Manufactured to the representation of Fig. 1, wherein the anodic contact terminal a Nickel foil and the anode was made of lithium; the cathodic contact connection was formed by one 60-mesh nickel shield while the cathode is a

ίο tablet was made from a 2-phenothiazine · 3J ₂ charge transfer complex, which was prepared by mixing and heating the phenothiazine and iodine in the specified proportions. The lithium anode surface abutting the cathode was coated with a film of LiI which was formed by exposing the surface to an iodine vapor in an argon atmosphere. The cell components were stacked and compressed at a pressure of about 77 kg / cm ² (1100 psig) to collect the complete cell. These cells were continuously discharged at a current of 25 μΑ at 33 ° C. The following table 3 shows the voltages resulting at different time intervals with a current consumption of 25 μΑ and the short-circuit currents.

35

Table 3 Short circuit sirom time Full at 2} μΑ /, IaAI (Sumdenl Current draw 1100-1600 0 2.6-2.7 250-400 25th 2.3-2.4 50-80 49 1.3-1.5 Example VII

Cells were produced as in Example VI.

mi! Except for the fact that the charge transfer complex contained different proportions of iodine. The cells were continuously with a current drain of 25 μΑ and periodic Measurements discharged, with the open circuit voltage

and the current output at a voltage corresponding to half the open-circuit voltage, as in the following Table 4, were measured.

table

cathode

1 East .eerldufspannung 46 hours U ₁ , (volt I 63 hours 2.7 16 sid. s: std. 2.7 2.7 2.9 2.9 2.9 2.8 2.8 2.9 2.9 2.9 2.9 2.9 2.9

Current output at half the open circuit voltage in μΑ

East

16 hours

46 hours! 52 mercenaries 63 hours

2-phenothiazine 2 J ₂ ..
2-phenothiazine 3V ₂ J ₂
2-phenothiazine 4 J ₂ ...
2-phenothiazine · 4 ¹ J ₂ J ₂ .

1500

2100

3100

550

53
50
50
50

12th
14th

The performance of cells or elements that _{contain 2 phenothiazine · 3I 2} or greater proportions of iodine are comparable when the element is discharged, although the initial cell performance with more iodine than 2 phenothiazine · 4I _{2 is} reduced due to the higher ohmic resistance of such cathodes is. If less iodine than about 2 phenothiazine · 2J _{2 is} used, then the performance over the entire lifespan is obviously reduced, due to the fact that there is less available iodine.

Example- VIII

Cells were produced in which a 2 phenothiazine 3J ₂ complex was mixed with a binding agent and applied to a nickel collector.

was deleted, followed by a contact against a disc-shaped anode made of lithium foil, so that 'a complete cell with 1.25 cm in diameter. The cells were down to zero voltage at one Discharge current density of 50 μΑ / cnr, which results in different binder proportions and charge transfer complexes resulted in the service life shown in Table 5.

Table *

Shares
2 phenothiazine 3 J ₂ Shares
binder lifespan
in hours 7th
8th
9 5
5
5 40
72
36

Example LX

A poly-4-vinylpyridine-J2 (P4VP-J ₂ ) complex was prepared by polymerizing 4-vinylpyridine in a benzene solution using a n-butyllithium polymerization initiator and then adding an excess of an iodine solution in benzene to make the 105 parts by weight of poly -4-vinylpyridine to 250 parts by weight of iodine-containing charge transfer complex to precipitate. The precipitate was filtered and dried in vacuo. 3 parts of the complex were then mixed with 10 parts of powdered iodine. This mixture was pressed into disks 1.25 cm in diameter at a pressure of about 3.5 kg / cm ^{2 for use as a cathode.} There were then cells as in FIG. 1, produced using this cathode material and a lithium anode cut from a 0.16 cm thick sheet, and using anode and cathode collectors; this cell was compressed at a pressure of about 0.70 kg / cm ² and poured into a polyester potting compound. The following performance data of the cell resulted from measurements:

Open circuit voltage 2.9 V

Short circuit current 2.5 mA

Lifetime at room temperature and a discharge with current densities of
50 μΑ / cm ² 333 hours

Lifetime at room temperature and a discharge with current densities of
100 μΑ / cm ² 141 hours

Cell voltage after 645 hours of discharge at room temperature and at current densities of 10 μΑ / cm ² 2.1 V

The same at 60 ⁰ C and

10 μΑ / cm ² 2.35 V

Same at -40 "C and
0.2 μΑ / cm ² 0.60 V

Another element identical to the previous cell, with the exception that 5-vinyl-2-methylpyridine was used in place of the 4-vinylpyridine, had a cell life of 250 hours at a discharge rate of 50 μΑ / cm ² at room temperature.

It thus turns out that batteries or primary elements with a lithium anode, which at the same time nor the new plastic cathode material according to a further feature embodiment of the invention use, have unexpectedly superior performance that is several times better than other lithium cells according to the invention; so have ίο primary elements with lithium anode and the new plastic cathode material excellent storage stability, long service life, high output voltage and high energy density, which are particularly important in application

areas where there is only a small amount of electricity drawn with a long battery life is required, for example as a power source or Power supply for implanted prostheses, such as pacemakers and the like.

The primary element has a theoretical energy density of 213wh / lb or 19.2wh / in ³ ; actual energy densities of 136wh / lb and 11.5wh / in ^{3 were} measured during the discharge of the primary elements at room temperature. The open circuit voltage for the cell is 2.87 V. Since the impedance is a function of the electrolytic conductivity, the curve of the cell voltage over the current shows a linear decrease in voltage with increasing current until the short circuit current is reached. Immediately after production, short-circuit current densities of 20 mA / cm ^{2 were} measured. At room temperature, the short-circuit current drops to 1 mA / cm ² after 20 days and to 0.5 mA / cm ² after 110 days.

With a constant current consumption with relatively high current densities, the voltage drop is linear over time. Such behavior is shown in FIG. 4 for primary elements which, in accordance with FIG. 3, have a lithium anode, a P2VP · 5J ₂ cathode and a zirconium cathode collector, the cell having been stored at room temperature for 1 week. In Fig. 4 the cell voltage is plotted against the discharge time at the given constant current densities and different temperatures for several cells with different thicknesses, the thickness of the cells having been selected in such a way that the desired cell capacity is obtained. The cell thickness is in the range between 0.03 and 0.25 cm, the anode making up about 20% and the cathode about 80% of the cell thickness. The discharge curves generally obey the following equation:

η = -C- (i / Af ■ T exp (865O / RT),

where I _{1 is} the polarization, C is a constant depending on the construction of the cell, i / A is the current density and t is the discharge time. The value of 8650 calories / mole is consistent with the published data for the activation energy of the ionic conductivity of LiJ. Using the novel cathode material, the constant C has a typical value of 1.25 x 10 ^-4 Ohm cm ⁴ / A to see.

6J Discharging the cells at lower current densities led to a remarkable decrease in polarization. For example, if the OW cm cell of FIG. 4 at 25 ^C C instead of 50 μΑ / cm ² with

25 μΑ / cm ² discharged, then the cell voltage rose from 0.24 to 216VoIt at 1000 hours. At 10 μΑ / cm ^2, the polarization per 1000 hours rose to a value of less than 100 mV, and the life of the cells was increased by a factor of 5.

While reducing the current densities and hence a longer life of the cells were clearly deviations from the linear gradients in the discharge curves, particularly at higher temperatures, which are to be interpreted as 2 eir result of self-discharge.

The self-discharge of the cells involves diffusion of iodine from the cathode through the electrolyte towards the anode, where additional electrolyte is then generated. Such an accumulation draws one Increase in the resistance after it has been found that this is more functional There is a connection:

U / A = Kf " ² exp (£ / J? R)

where Ω is the increase in resistance per unit area and t is the time. Both the constant K in front of the exponent E and the term in the exponent have been determined for cells during storage for one year at temperatures between -55 and +75 ⁰ C. For lithium anode cells using P3VP · 6J ₂ cathodes, the result is a typical value of K of ^{1.6-10 5} coul / cm ² · see ¹ ' ² and a value of E of -9950 calories / mol. After a storage time of one year at 75 ° C., a typical primary element with an initial impedance of 30 ohms has an internal resistance of about 16,000 ohms, both values being measured at this temperature. The same cell at a storage temperature of 25 ° C shows an internal resistance of about 11,000 ohms, which has increased from an initial 150 ohms.

As a result, only as an example! called a cell with the dimensions of only 4.45 3.50 χ 0.93 cm, which is discharged with a voltage of at least 2.3 V at 37 ° C with a current of 30 μΑ, for use in prosthesis-like arrangements a projected service life of at least 10 years. Even after long storage times, cells can be operated over a wide temperature range for many years with current draws in the range of μΑ. If cells door are designed for very long storage times, for example for 10 years, then the cell thickness is increased in order to take account of the increasing self-discharge. The same performance capability is obtained regardless of whether one uses either P2VP · nJ ₂ or P2VQ · nJ-, or P2VQ · nJ ₂ .

It must be noted that the new cathode material is also used to advantage can be used with anodes of other metals that are reactive with iodine, such as silver or magnesium. For further explanation see

pointed out the following. A 1 '/ ₂ "x IV2" ^x 0.020 "sintered silver anode (with a porosity of about 50%) was ^{filled with 0.036 in 3} of P2VP · 5J ₂ to make a cell 0.026" thick. Contact with the cathode was effected by using a zirconium cathode collector. This line had an open circuit voltage of 0.67 V. After a discharge for 170 hours with 1450 μΑ at 24 ⁰ C, let the cell voltage only drop to about 0.52 V; if the battery continued to discharge with the same current, the cell voltage finally dropped to zero after about 200 hours. In this embodiment, the silver anode was a sintered mat of 0.005 "χ 0.009" χ 0.125 "silver needles weighing 3.7 g. Other electrode shapes can also be used, for example foils, screens or electroplating, but the best performance was achieved with sintering A group of 6 cells with a silver foil _{anode and a P 2 VQ · 5J 2} cathode had an average life of 987 hours immediately after production with a discharge of 10 μΑ / cm ² at 25 ° C; 6 identical primary cells had after a storage time of 30 days an average life of 841 hours under the same discharge conditions. In contrast to lithium cells, only about a third of the theoretically available electrochemical capacity is realized in silver batteries; this is due to the inability of the silver to adapt to the growing silver iodide electrolyte resulting in a loss of p physical contact between the anode and the electrolyte.

In another embodiment, a cell of stacked lamellas of a magnesium _{anode, with a P 2 Vp · 5 J 2} cathode and a zirconium cathode collector had an open circuit voltage of 0.95 volts and a short circuit current of 2 mA / cm ² . In the case of discharges with a current density of 10 μΑ / cm ^2, these cells had a service life of about 50 hours.

For this purpose 2 sheets of drawings

Claims (13)

Patent claims: 1. Primary element with a negative lithium electrode, a solid lithium iodide electrolyte and an electrically conductive one containing iodine positive electrode, characterized in that the positive electrode (6,22) consists of an electrically conductive charge transfer complex, Consists of an organic donor component and iodine. 2. Element according to claim 1, characterized in that the positive electrode (6,22) is carbon contains. 3. Element according to claim 1 or 2, characterized in that the surface of the negative The electrode is coated with lithium iodide. 4. Element according to claims 1 to 3, characterized in that the organic compound is a heterocyclic nitrogen compound. 5. Element according to claims 1 to 4, characterized in that the organic compound is a phenothiazine. 6. Element according to claim 5, characterized in that the ratio of the phenothiazine to iodine is between 3: 1 and 4: 1. 7. Element according to claims 1 to 4, characterized in that the organic component is a polymer of a vinyl compound having a heterocyclic nitrogen substituent. 8. Element according to any one of claims 1 to 7, characterized in that the organic component is a poly-4-vinyl pyridine. ■ 9. Element according to claims 1 to 4, characterized in that the organic donor component is a polycyclic aromatic compound. 10. Element according to claims 1 to 4, characterized in that the positive electrode is a plastic mixture of iodine and a charge transfer complex consisting of Iodine with an organic donor component selected from the group consisting of poly-2-vinylquinoline and Poly-2-vinylpyridine is selected and has between 2 and 15 iodine molecules for each nitrogen atom contains. 11. Element according to any one of claims 1 to 4, characterized in that the positive electrode contains between 2 and 6 iodine molecules for each nitrogen atom. 12. Element according to one or more of claims 1 to 11, characterized in that for the positive electrode (6, 22) a current collector (8, 10; 24) is provided, which consists of a Metal from the group of zirconium, platinum, nickel or alloys of the same. 13. Element according to one or more of claims 1 to 12, characterized in that the components of the element enclosed in a flexible plastic film or a potting compound which are essentially impermeable to iodine, oxygen, nitrogen and water vapor is.