DE2056913C3 - Electrochemical cell with fluoride solid electrolytes - Google Patents

Description

The invention relates to electrochemical cells and components therefor, in particular for oxygen sensors and power sources that use solid electrolytes.

Although the use of solid electrolytes in electrochemical cells is economical to manufacture of power sources, batteries and similar devices of improved structural robustness, Accuracy and efficiency, e.g. B. has made it possible to avoid the development of gas etc. Finding compatible components for the cell anode, electrolyte and cathode is much more difficult than was the case with the cells known earlier, those with liquid or semi-liquid Electrolytes work.

Apart from this, there is another difficulty in forming solid electrolyte cells for special purposes. So are involved in the formation of an electrochemical cell Oxygen sensing cells have been developed that work with various liquid electrolytes, such as it z. B. in U.S. Patent £ 913,386 is. It is characteristic of such sensor cells that their electrolyte, apart from other properties, the common feature of such aqueous electrolytes is the ability to be practically complete Has ion dissociation, which removes the oxygen ions that are in the cell from the oxygen of the Forming an environment, gaining flexibility. If you use solid electrolytes in such sensor cells it would be possible to make them miniature size and robust; but solid electrolytes suffer very little dissociation, and there are many electrolytes with lattice structural features that have the Virtually exclude mobility of the oxygen anions.

In the above-mentioned type of application of the cell, as in the cell according to the United States patent 2 913 386 and similar sensor cells, the excitation voltage is supplied by an external power source, e.g. B. a battery, which has disadvantages in terms of cost and size. This State leads, in addition to the requirement of the compatibility of the constituents and the ion mobility, to a need for a self-sustaining cell based on a solid electrolyte for measuring the oxygen concentration in the

and a need for a power generating cell.

Another field of application in which there is a need for electrochemical cells with solid Electrolytes, are those that affect the environment

talking power sources, such as the »Inter-Vivos power sources«, which are of particular importance in the field of biomedical electronics. In contrast to the sensor cell according to US Pat. No. 2,913,386, which is ultimately an external

»Ο Power source modulated so that an indicating Ammeter is energized according to the oxygen concentration in the area, is the Inter-Vivos power source Intended for the direct intravenous arrangement and delivers without the involvement of an external Power source a small amount of electricity, being fed by the oxygen carried by the blood will.

The object of the invention consists in an electrochemical cell which can be used for the purposes mentioned above suitable and has compatible ingredients including a solid electrolyte, in which the oxygen anions have a high degree of mobility.

According to the invention, this object is achieved in that the electrolyte consists of a solid fluoride Rare earths in the form of a thin foil and the anode consists of a metal that is resistant Forms fluoride.

The electrolyte preferably consists of lanthanum fluoride, praseodymium fluoride or neodymium fluoride.

The anode and the cathode are also preferably made of dissimilar metals. Depending on the Work functions of the metals chosen for the cathode and the anode can make the cell a current-generating one To be a cell or not. If the electrochemical cell is a power-generating cell, the cathode represents correspondingly the positive electrode and the anode the negative electrode. If the cell Enclosed in a protective housing that is impermeable to oxygen and is ■ iron-generating, it can be used as Battery can be used.

In a preferred embodiment of the invention, the anode consists of a metal that is also forms stable oxides. When the cell is exposed to ambient oxygen and generates electricity, it can either act as a source of electricity that is responsive to the environment or as itself self-maintaining oxygen sensors can be used. When the cell is exposed to ambient oxygen exposed and not generating electricity, it can be used as an oxygen sensor in conjunction with an external power source will. When the cell components when using the cell as a power source or as an oxygen sensor Being adversely affected by the action of the environment, the cell turns into a for oxygen Permeable protective housing included.

Preferably there is the anode and the cathode

^ uitrit

■ If

Made of metals with such emergence work that true and a direct short circuit between the

To prevent an open circuit potential films 12 and 16 between the electrodes is located above

difference of at least 0.2 V. the anodic film strip 12 a and the carrier 10

To further explain the invention, an insulating layer 20 which includes the strip 12 a

Reference is made to the drawings. 5 and electrically isolates it from films 14 and 16.

Fig. 1 is a plan view of a preferred electrical connection to the cathode

Embodiment of a film 16 built according to the invention is represented by the strip 16a and the

ZeUe; . final pole 166 made. Since the strip 16 a

Fig. 2 is a section mch the line H-II that protrudes from the cell, it comes only with the isolating

Fig- 1; ίο generating film 18 and the insulating support 10 in

F i g. 3 is a partial section along line IH-III of the contact. Since there is no electrical contact with the

F i g. 1; underlying included films 12 and

F i g. 4 is a plan view of another embodiment 14 is made in connection with the strip

tion ^ form of a cell built according to the invention; fen 16a no isolating element required.

Figure 5 is a section on line V-V of Figure 15 for making those shown in Figures 1-3

Fig. 4; Cell are the various films in a vacuum

Fig. 6 ^; is a top view of a further execution through corresponding masks on the carrier

Approximate form of a cell built according to the invention; ger 10 vapor-deposited For example, a glazed

F i g. Fig. 7 is a schematic representation of a 0.8 mm thick alumina plate which is a Device for determining the oxygen concentration - ao glaze made of borosilicate (743) carries, together with vertebration, which works with cells according to the invention; steam boats, in which the individual

F i g. 8, 9 and 10 are diagrams of the performance components for the sensor films, in a var

characteristics of the environment responding vacuum evaporation chamber introduced. The carrier

the current sources with cells according to the invention; becomes selective by means of a turntable or carousel

11, 12 and 13 are diagrams of lines 35 in the target position above the boats in question.

Performance characteristics of batteries brought with cells. Between the boats and the steam

work according to the invention. the goal is vaporization masks on a second

First of all, the cell structure and the proboscis are to be arranged, which are then lifted

The manufacturing method used will be explained. Thereafter, that the mask in question with the wearer in

the electrochemical processes involved in contact are discussed. The chamber is made with the help of a

presumably take place during the operation of the cell, where- ion absorption pump evacuates to 2.5 · 10 ~ ⁸ torr,

in particular on the above-mentioned application and during steaming, the pressure is on

species is referred to. Then, 2 to 4 x 10 ^-7 Torr is maintained. The carrier is on

Examples for the application of the cell are given. heated above 125 ° C to remove water and other adsorbents

The structural debris shown in FIGS. 1, 2 and 3 should be removed. Then the order of the electrochemical cell comprises an iso-anode film vapor deposition mask by lifting to the leaning support 10, a thin film of anode abutment brought against the support and the boat metal 12 over the support, a thin film of having the anode film material in registration with the solid electrolyte 14 moved over the anodic film carrier and the mask. Thereupon, the and the carrier and a thin film of cathodic material with the aid of a previously determined and set on the metal 16 over the electrolyte and the carrier, a sufficiently rapid evaporation. The thin film 18 is heated over the cathodic current, with the evaporation rate film and the carrier. The film 18 can be selected depending on the duration of each material so that the intended use of the cell forms a smooth and uniform layer on its own.
Oxygen permeable or impermeable to oxygen. 45 After the vapor deposition of the anode film, the permeable materials will exist, as described below with the material for the insulating film 20 in FIG. If the environment allows this and the shape of the insulated detects, the film 18 can be left completely exposed. films corresponding mask against the

In this arrangement, the cell parts 12, 14 odenfilm-evaporated carriers are raised. On that

and 16 are formed as circular films, the con-50 the insulating film 20 is formed on the in FIG. 1 shown,

are arranged centrally to the center of the cell. limited anode film area evaporated.

The film 14 is in direct contact with the FiI After the vapor deposition of the insulating film 20 on the

men 12 and 16 and separates both from each other. Therefore, the carrier and the anode film 12 is the Veidamp-

the entire power line between the anodizing boat with the electrolyte film material in the target

between film 12 and the cathodic film 16 brought through 55 position and the required for the electrolyte film

the electrolyte film 14. Although all of these films have an extra evaporation zone instead of the anode film

that are in contact with the carrier 10, they are masked by lifting against the carrier to

not conductively connected to one another, since the carrier brought gene, whereupon the vapor deposition with the

is an insulating body. The same goes for the film 18 that carries electrolyte film. Like F i g. 3 shows is the

which is also electrically isolated. 60 evaporated electrolyte film in a limited part

The anode film 12 has a strip 12 a, its circular circumference through the insulating

which is isolated from the anode film 12 via the films 14 and 16 (FIG. 3) to form the layer 20. One holds

Extends the outside of the cell and in the process the temperature of the support to about 125 ⁰ C and

terminating pole 12ft (Fig. 1) ends, through which an electric sets the evaporation with relatively less

see connection to the anode film being made. This leads to the training of a

can. To the geometrical formation of the cell a smaller number of grain boundaries, a small one

in relation to the conduction of current from the anode to the internal electrolyte resistance and avoidance

Cathode through the fleece film 14 to form an amorphous electrolyte structure.

5 J 6

In the next process step, the cathode is applied to the carrier, then the insulating film 30 is applied to the

denfilm 16 vapor-deposited by the boat with cathode film 28 and the carrier 10, then the elec-

the cathode film material and the relevant application film 32 on all underlying films and

brings steam mask in the target position. As in Fig. 1 vapor-deposited the carrier, as shown in FIG. 5 shown

shown, the cathode film mask is formed as 5 is, and finally the film 34 is on the insulating

that apart from the actual inner circular film 30, the electrolyte film 32 and the carrier 10 are

gen cathode film nor the strip 16 a and the vaporized.

form the final pole 16 b . As Fig. 2 shows, the A rectangular film formation, which has a similar-

Strip 16 a and the terminal 16 b directly on Chen uniform electrolyte path 38 between the

the carrier 10 is evaporated, while all the remaining io anode film 40 and the cathode film 42 are available

Parts of the cathode film on the electrolyte film 14 supply is shown in Fig.6. Here is the

and the insulating layer 20 (FIG. 3), cathode film strips 42a are vapor-deposited in an insulating manner from the insulating layer.

the. Finally, the film 18 is wildly evaporated by including film 44 and carrier 10,

you the corresponding evaporation boat and you The through the cell structure in the above-described

brings the appropriate mask into the target position. The 15 above embodiments achieved uniformity

This film is applied to the whole exposed area of the electrolytic way is of particular benefit when

With the exception of the terminal pole, the cathode film 16 has a high degree of oxygen sensitivity

16 ί) and most of the strip 16 a should have. On the other hand, if the cell is used as a battery

steams. This film, as shown in FIG. 3 shows with which or for purposes of use it is intended

Insulating film 20 in contact. 30 does not indicate a high degree of oxygen sensitivity

As with vacuum vapor deposition vi η glass or Ke- it is sufficient, only usual for distance between ramik with metal layers, it is also in the anode and the cathode and plektrischen Kon-frame of the invention, the films with sublayers both with the electrolyte to clock care for,
to be provided so that they adhere firmly to the carrier. The operation of the cell will now be discussed under For example, within the scope of the invention, this reference to the above-mentioned application of electroless deposition of a thin chromium film for purposes will be discussed, with the application of one to the carrier 10 and on other carriers being described first, before the cell is described the vapor deposition processes described above are required to be sensitive to oxygen,
will. For such purposes it is an important

Another embodiment of the cell is shown in FIG. 4 30 essential prerequisite that the current conductivity and 5 are shown. Here, the anode film of the cell changes with the oxygen concentration in the 26 and the cathode film 28 on the carrier 10 changes into cell electrolyte. Such a change in the same plane, the anode strips 26a and 266 is preferably linear; but it need not be fitted with connectors are provided poles 26c and 26 d, currency proportional to the oxygen concentration to be; it rend the cathode strip 28 a with a terminal 35 only needs to be reproducible, that is, the conductivity pole 28 b is provided. An insulating film 30 is located above the cathode strip 28 a of changes in an oxygen reference concentration and the carrier 10, up to predetermined oxygen concentrations only the central circular part 28 c of the ca with the same changes in the oxygen concentrate cathode film with the overlying electrolyte should always be the same Have size. When the conductive film 32 comes into contact. The film 32 does not enclose any change in the ability linearly, but reproducibly and touches practically the entire anode film 26. If the insulating film 34 is located directly above the non-linearity in the associated cell current, the electrolyte film 32, the insulating film 30 and the carrier - Install a display circuit, eg you can use 10th logarithmic or similar measuring devices.

From Fig. 4 it can be seen that a suitable oxygen sensitivity is linear or non-linear Form of anodic and cathodic vapor-near nature requires that the cell on entry masks as well as by using the insulating oxygen works by doing the various layer 30 a special geometric relationship anions of oxygen, z. B. O. ~, electrolytically in between the anode film 26 and the cathode film. The Lei-28 is placed in a liquid electrolyte will be produced. In this way, there is of course no obstacle to avoiding these anions circular electrolytic path 36 against. In the above-mentioned US cell. -Between films 26 and 28 through film 32 Patent 2,913,386 and similar cells is dei through it, as is also the case with the one shown in FIG. 1 electrolyte consisting of aqueous potassium hydroxide illustrated embodiment was the case. Each practically perfect in alkaline cations and halo, if any The tendency of the cathode strip 28 a to dissociate at 55 gene anions, and practically all ion arteries Power lines in the cell actively participate and th are mobile. In contrast, dissociators the practically uniform electrolytic path of solid electrolyte only to a very small extent, unc To change between the anode and the cathode, there are many electrolytes with such a lattice structure The insulating covering of the strip will indicate that the oxygen anions are present at all times 28 a thwarted by the film 30 and the carrier 10. 60 can't move.

Likewise, the disturbance of this electrolytic We- Apart from this characteristic electro

ges by the anode film thereby prevented that lytgitterstraktur, of which the electroiytische conductive

the anode film at 26 e and 26 / in the vicinity of the speed depends, the characteristic chemi

FOms 30 recedes in its surface to the outside. see compatibility, d. H. the transformation of be

When producing the oxygen anions shown in FIGS. 4 and 5, this must be taken into account. Ii

The first cell in the vacuum chamber is that of the cell according to US Pat. No. 2,913,38)

Anode film 26 on the carrier 10, then the in the be by the abundant presence of what

cathode film 28 lying on the same plane, or as it was also in the patent

1515

The lanthanum difluoride cation is practically unaffected.

Lytes supplied with hydrogen ions, easily chemically displaceable, and the gold cathode only supplies electrons. Allows reactions that result from moving if oxygen enters the cell electrolyte as a result of the Chen oxygen anions form hydroxyl anions and pass through the permeable film of the sensor eventually water is created. In the case of non-aqueous electrolytes, under the influence of the applied potrolytes, such a reactivity of the acid potential is electron capture, and it does Substance not readily given. play apart from the reactions given above

Probably due to the provision of these species-specific sub the following cell reactions from: differences in the electrical and chemical properties between the previously known sensor cells 10 _to ^ j £ _a thcd _e · and those that a similar provision of the oxygen concentration with upstream in the solid state O ₂ + e ~ - »· Og- (electron capture) enable lying constituents, it has been possible to: At the anode:

determine further fundamental relationships, the λ α λ. η - tar \ λ. -

for sensor cells with solid electrolytes of high 15 4Ag + υ _Ε - * 2Ag ₈ U + e

Performance are required. The electrolyte

can in part be defined as one that is obviously required for the electrodes

Room temperature is characteristic of fluorides and oxides that are stable for the cell anode Solids has high anionic conductivity. Fer- forms, while the cell cathode is an indifferent one But such an anionic conductivity must be on ao ladder. Examples of different metals that are used for Anions that are large in size can be used with the acidic cell electrodes impact anions are comparable. A relatively high dielectric constant is also desirable for the cathode gold, platinum, rhodium and pa possible. This electron capture takes place with water erigen electrolytes easily because the water placed one assuming the absence of water Has a dielectric constant of 78.5. Experiments have shown that water If the electrolyte is rich in solid electrolytes, the dielectricity - the sensitivity of the cell to oxygen - does not have constant but nowhere near this value. influenced. On the other hand, the sensor needs

It has been found that the fluorides of the rare 30 in contrast to the above-described known pre-earth metals, i. H. The fluorides of scandium, yttrium, do not provide any water vapor for its working ability of lanthanum and the metals of the lanthanide series.

(Atomic numbers 58 to 71), such as cerium, praseodymium, the feeler can be a permeable film (18 in

Neodymium and erbium, especially Fig. 1), have a barrier layer for solid have those properties that show up as emergency or liquid contaminants from the environment Manoeuvrable for a solid electrolyte for oxygen, but the oxygen can enter the cell feelers have proven. leaves. Such a membrane can, for. B. made of polytetra-

The anionic conductivity of these compounds, fluoroethylene or made of polyethylene, is in the range from 10 ~ ⁷ to 10- · S / cm. In addition to the permeable film and the electrical

Because the rare earth metal fluoride has a high density 40 chemical cell, the sensor can have a carrier (10 Schottky impurities, ie vacancies in the crystal in FIG - A casual film forms a housing that protects the cell from its normal location at or near the crystal super-impurities. Because the film creates oxygen surface. At room temperature these can be permeated, the carrier made of materials fluoride can be more than 10 ¹⁹ fluorine vacancies per cm ^s , 45, which are impermeable to both impurities and for and the vacancies are large enough to be impermeable to the moving oxygen, like glass or ceramics, the possibility of the relatively large oxygen anions. Finally, it was found that they consist of a material which, through the dielectric constants of these compounds, enables oxygen to enter the electron through oxygen for pollutants contained in the environment. 50 cleanings, however, is impermeable.

The requirements for the electrodes of according to The relative positions of the anode metal and

Oxygen sensor cells built according to the invention result in the cathode metal in the voltage series of the Mesich from a consideration of the electrochemical talle determine whether the sensor reactions according to the invention, which presumably take place therein. With cells themselves a potential difference (of about 0.2 V) an electrochemical sensor cell according to the invention between the electrodes, an electrolyte film of lanthanum fluoride in electron capture by oxygen, d. H. for the bond Connection with a silver anode and a gold of electrons to oxygen molecules, is sufficient or cathode used If an external power source is required for these electrodes. if Essence of oxygen a potential difference to the cell z. B. from a bismuth anode, a gold is placed, the following 60 cathode and an electrolyte made of lanthanum fluoride are likely to play Cell reactions from: exists, a holm electrolyte forms between the electrodes: higher potential difference than it is for the electro trapping by oxygen is necessary. If theoretical {LaF ₈ 3 + LaF ₈ : £ LaF ₂ ⁺ + F "table this potential difference is 0.57 V, and in

At the anode- ^{6s of the practice Kt} ^ * ⁵ * PotentialdSierenz, as next-

^ _ hend shown has been nearly achieved. If

Ag + f ^ Agf + e _but , jj _e wisrautanode replaced by a superanode, Ag: £ Ag + + e- as with the cell, its electrochemical reactions

1515

Ct \ J SJ \ J sj t. ^ i

but have been discussed, theoretically only one example 1

potential difference of 0.11 V can be expected. One

such a potential difference between the electrodes. A sensor cell of the type shown in FIG. 1 to 3 shown

But not enough for electron capture by construction using a glazed one

Oxygen off, and therefore in this case one of S is aluminum oxide plate, silver for the anode film,

externally applied potential difference required. Lanthanum fluoride for the electrolyte film, gold for the

If the cell anode is made of a metal, cathode film and polytetrafluoroethylene for the

that forms stable fluorides and oxides as it is made for permeable film. The film thickness is

If an oxygen sensor is required, the cables can be 2000, 1000, 2000 or 2000 A. The insulating layer

The ler cell assembled with other devices is made of silicon dioxide.

The connection terminal 16 b of the cathode film is used to obtain an oxygen sensing device

as shown in FIG. 7 is shown. connected to the negative pole of a power source,

When using the in F i g. 7 one pole of a micro-micro-ammeter shown in the figure is placed in the sensor cell, which itself does not supply a sufficient potential difference with the positive pole of the power source between the electrodes to connect electrons and 15 earthed, and the other pole of the ampereme to bind oxygen atoms, is an outer age is connected to the terminal pole 12 b of the anode film electrical circuit in which a current indicator 22 is connected. The sensor cell is connected in atmospheres and a power source 24 connected in series with oxygen ^{contents of 0, 21 or 100 0} / o, connected to the connection poles 12 b and 16 b , the rest of which consist of nitrogen,
the. This creates a suitable potential difference. A voltage of -0.5 V, ie more than 0.2 V, is applied to the cathode. The reading of the current is in the anode film 12 and the cathode film 16, the first atmosphere for 6 x 10 ^{~! 2} A, in the second Atmoinfolge the penetration of oxygen into the electron sphere 1.75 x IO ^"11 A and in Third atmosphere trolyte film 14 changed by the films 16 and 18 6.2 x 10 ~ ^u A. If the cell conductivity is repeatedly exposed, the same current-current indicator is displayed without further ado from the three atmospheres, and this display is displayed a strength reading within a margin of error of a measure of the oxygen concentration in the area 5%.

exercise of the film 18. If one uses the other type B e i s ο i e 1 2

the sensor cell according to the invention, namely the ^

The self-sustaining cell used is the 30 A sensor cell of the type shown in FIG. 4 and 5 shown

Current source 24 by the in F i g. 7 with dashed design is made using a glazed

Lines shown connecting line 25 replaced. In aluminum oxide plate, silver for the anode film,

In this case the sensor cell itself supplies a potential lanthanum fluoride for the electrolyte film and gold for the

tial difference between the electrodes of more than cathode film and polytetrafluoroethylene for the

0.2 V, which is produced for the binding of electrons to acidic 35 permeable film. The film thickness is

material is sufficient. gen 2000, 1000, 2000 or 200 A. The insulating layer

In the case of the sensor cell according to FIG. 1 to 3 must consists of silicon dioxide.

Oxygen through the films 18 and 16 penetrate the terminal pole 28 b of the cathode film is connected to gene to get to the electrolyte film 14 and the negative pole of a power source to change a conductivity of the cell. With this arrangement, the cathode film 16 must therefore be permeable in series for the positive pole of the power source which is grounded to oxygen. However, this provides no particular switched on, and the other pole of the ammeter is difficulty, since one by suitable choice of the geo- to the two connecting poles 26 and 26 of the c Anmetrischen formation of the film and the parameter d odenfilms connected. The sensor cell is produced in 100 per cent steam process with a high level of permeability for nitrogen or 100 per cent for oxygen. So z. B. introduced.

The cathode material, preferably in the form of tiny islands, is applied to the cathode with a voltage of - 0.5 V, so that one misplaces. In the nitrogen, the reading is the federal film that is porous to oxygen molecules. Current strength 2 · 10 ^-10 A, in the oxygen it is a special advantage of the design of the sensor according to 50 12 · 10 ^-10 A. With repeated exposure to the same F i g. 1 to 3 consists in the fact that the same amperage film 18 is obtained when the atmosphere is damaged, for example by abrasion, only noble metal, not readings within an error limit of 5%. but the more sensitive to contamination. The sensor cells according to the invention are placed within the electrolyte film 14 of the action of the environment from a region of voltage applied to the cathode. 55 voltages from - 0.2 to - 0.7 V against oxygen

In the manufacture of oxygen sensor cells and sensitive. Eg game 3

of oxygen-sensitive power sources that

will be described in more detail below, a FöhlerzeHe is shown in Figs It is also within the scope of the invention, the electrolyte type is made using a glazed part X-ray film to irradiate the 60 aluminum oxide plate, gold for the cathode film, To enlarge Schottky impurities, as well as excess praseodymium oxide for the electrolyte film, bismuth for Sige fluorion vacancies in the electrolyte for the anode film and polytetrafluoroethylene for the supply by making the electrolyte with the fluoro-permeable film. The film thicknesses bend of a divalent metal to carry 804, 2744, 3174 or 2000 A. The isolation sensitivity to increase against oxygen. 65 film is made of silicon dioxide. Between the anode

The Ariseftweise of Fig. 1 to 3 and and the cathode is an open circuit voltage voi The M network parts built according to Fig. 4 and 5 are in 0.40 V, the seven between the connecting poles (21)

* .- s- «... * _ * ..._" .- ,. «._..-.,.«. and 166 can measure the poles of an MSkro-Mikro

1515

11 ^v IZ

With these connection poles, amperemeters are used for various other purposes in limited

bound. An external power source can easily be used in unused rooms as described above.

det. The sensor cell is produced in an atmosphere using evaporation methods. Since the cell further

Bracht that contain 0, 21 or 100% oxygen. does not contain any liquid components that could

The amperage read on the ammeter 5 zen, vibrate or shock-triggered power

is 2 · 10 ~ ¹⁰ A in the first atmosphere, in which deviations could cause the

second atmosphere 4 · 10 ~ ¹⁰ A and in the third sensor built according to the invention slightly more robust

Atmosphere 1.2 ■ 10 ~ ⁹ A. Establish type of construction, e.g. B. for wastewater treatment,

". . . . in which the biological oxygen demand is determined

^Beis P ^{iel 4} ίο becomes.

A sensor cell of the type shown in FIG. 1 to 3 shown In these applications, which maintain themselves

The design is according to example 3, but requires sensor cells with neodymium, the combination

fluoride instead of praseodymium fluoride. ions of anode and cathode metal, as above

The film thicknesses are 878, 2598, 2200 or described and explained in Examples 3 to 6,

2000 A. The insulating film is made of silicon dioxide. 15 selected according to the voltage series of the metals so that

There is one difference between the anode and the cathode in their work functions

Open circuit voltage of 0.36 V, which is between the electrodes (open circuit) potential differences between

Connection poles 12 b and 16 b can be measured. The poles of the electrodes give at least 0.2 V, such as

of a micro-micro-ammeter they are required for electron entry through oxygen.

connected to both terminals. An outer ao hch are. In Examples 3 to 6 a preferred

Power source is not used. The sensor cell is a combination of anode and cathode metal

is used in atmospheres with oxygen levels of 0, namely bismuth and gold. Others

21 or 100 · / · introduced. The readable current reversible combinations are e.g. lanthanum and gold,

strength in the first atmosphere is 5.5 10 " ¹⁰ A, lanthanum and rhodium, beryllium and platinum, etc.

in the second atmosphere 1.04 · ΙΟ " ⁹ Α and in the» 5 As can be seen from Examples 1 and 2, deliver

third atmosphere 3.0 · 10 ^-9 A. those metal combinations in which the un-

_R. . differences in the final work a lower position

Example 5 generate potential difference as it is for the electron-A sensor cell of the in F i g. 1 to 3 depicted oxygen capture is required, e.g. B. Silver design is made according to Example 3, but with cerium fluoride 3 »and gold, sensor cells, which are used there instead of praseodymium fluoride. They can, where the connection to an external current film thicknesses amount to 3495, 7497, 1866 or 2000 A. source can be accomplished without difficulty.
The insulating film is made of silicon dioxide. Between the use of the cells according to the invention of the anode and the cathode there is an open circuit as oxygen-sensitive current sources that require a voltage of 0.24 V, which is between the terminals, the cell maintains itself, ie that it has one for terminal poles 126 and 166 can be measured. The poles of a potential difference micro-micro-ammeter that is sufficient to capture electrons are generated between the electrons with these two rence. Cells of the connection poles connected. An external power source of the type according to FIGS. 1 to 6 are therefore suitable for is not used ^for the cathode contain material selected in this way. The read current is to be that a potential difference between the first atmosphere is produced in the 1 x 10 ~ ¹⁰ A, in the second electrode of at least 0.2 volts.
Atmosphere 2.75 · 10 ^{-10 A and in the third atmosphere 9.7-10 ~ 18} A. In a preferred power source according to the Ersphere 9.7-10 ~ 18 A. invention, an electrolyte film made of Lantban fluoride in. 45 Connection with a bismuth anode and a gold

Example 6 cathode used. In the absence of oxygen, a sensor cell of the type shown in FIG. 1 to 3 play out, as one assumes, the following cell construction is according to Example 3, but with lanthanum reactions:
fluoride instead of praseodymium fluoride. _T _ Flektrnlvtpn
The film thicknesses are 2015, 8635, 4320 or 5 ° * ™haben y ™ "-

2000 A. The insulating film is made of silicon dioxide. l ^LaF aJ + ^Lat »* · ^LaF t + ^b

Between the anode and the cathode there is an anode:

Open circuit voltage of 0.50 V, which is between the Bi + 3 F ~ ^ BiF + 3 e ~

Connection poles 12b and 166 can be measured. The poles "· _". ". + + + ,,

of a micro-micro-ammeter are used with these 55 "*" ^e

Connection poles connected. An external power source The lanthanum fluoride cation is practically unaffected

is not used. The sensor cell becomes atmospheric and the gold cathode only supplies electrons.

Spheres introduced, the different oxygen concentration from the voltage series of the metals is calculated

Have centrations, the in the examples having a theoretical open circuit voltage of 0.57 V. At

3 to S specified currents can be determined. 60 Presence of oxygen in the cell electrolyte

In view of the very minorities described above, in addition to the above reactions,

The thickness of the cell in the oxygen line according to the Er- borrowed the following cell reactions:
Fume used to find the device

Easily made in miniature and micro-miniature size - At the cathode:

In this way, sensors of a suitable size for 65 O. + e- - * - O, - (electron capture)
Applications such as medical diagnosis,

z. B. for the determination of the sanitary material stress in the ^{Αλ of the} A »« «

Blood by direct intracellular measurement, and for 4Bi + 3Ο ₂ ~ -> 2Bi ₁ O, + 3 e ~

1-515

13 ^ 14

Other suitable combinations of anode and example 8
Cathode metal graze according to the series of voltages

Metals selected so that the differences in the A power source shown in Figs. 1-3

Work functions of these electrodes (open circuit) which are used for construction is made using a glazed

5 aluminum oxide plate required for electron capture of oxygen, bismuth for the anode film,

Potential difference between the electrodes of praseodymium fluoride for the electrolyte film and gold

generate at least 0.2 V. Examples of verscbie- made for the cathode filra. The film thicknesses

denier metals used as cell electrodes carry 3174, 2744 and 804 A respectively.

are for the cathode gold, platinum, between the connection terminal 126 of the anode film

Rhodium and palladium, and for the anode silver, io and the terminal pole 166 of the cathode film

Zinc, bismuth, berryllium, cadmium, rubidium, an open circuit voltage of 0.5 V was measured. To

Lanthanum, iron and BIeL Other suitable grains connecting a load resistor of

combinations of anode and cathode metal as 1.0 · 10 ⁹ ohms at the terminal poles of the films

Bismuth and gold are z. B. Lanthanum and gold, one in an atmosphere with an oxygen content

Lanthanum and rhodium, beryllium and platinum, etc. 15 of 0% (a pure nitrogen atmosphere) one

While the above equations under the on-output voltage of 0.25 V, which is a working

Assumption of the absence of water vapor recorded current strength of 2.5 · 10 ^-10 A results

tests have shown that the sensation when the power source is in an atmosphere with

possibility of the power source against oxygen due to an oxygen concentration of 21%> spent

steam is not affected. ao is obtained with the same load resistance

The operation of the power sources according to the er- an output voltage of 0.37 V, the one

Finding is explained in the following examples. Working amperage of 0.37 · 10 ~ ⁹ Α results, ie

. . an operating current one and a half times as large as

Β e 1 s ρ 1 e 1 7 _me j _ner atmosphere with an oxygen content of

A current source of the as 0% shown in FIGS. 1 to 3. With constant load, the output type increases is decreased by 0.027 V over 12 hours using a glazed voltage. Alumina plate, bismuth for the anode, the performance characteristics of this cell is in Lanthanum fluoride for the electrolyte film and gold for Fig. 9, in which the relationship between made the cathode. The film thicknesses are the pole voltage of the power source and the output 4320, 8635 or 2015 A. 30 Amperage for a change in the load

Between the connection pole 126 of the anode film resistance of 10 ¹⁰ to 0 ohms is specified, if

and the terminal post 166 of the cathode film, the power source is in an atmosphere with a

an open circuit voltage of 0.5 V. After the constant oxygen content of 2 IVe is located. the end

Connecting a load resistor from this diagram shows that the effective

I ₁ O-IO ⁹ ohms to the terminal poles of the films obtained internal resistance of the current source 35 approximately 2.0 x 10 ⁸

one is in an atmosphere with an oxygen concentration ohm and the power source is in relation to

step of 0% (a pure nitrogen atmosphere) the maximum permissible output current strength itself

an output voltage of 0.15 V, which limits a working. With an output current of approx

A current of 1.5 · ^{10 ~ 10} A results. 2.2 · 10 ~ ^e A, the output voltage drops to zero.

If the power source is in a 40

spent at an oxygen concentration of 21% Example V

is obtained with the same load resistor. A current source as shown in FIG. 1 to 3 shown

stood an output voltage of 0.4 V, which is a type using a glazed

Working amperage of 0.4 · 10- ^fl A results, i.e. almost aluminum oxide plate, bismuth for the anode film,

three times the working amperage for an acid 45 neodymium fluoride for the electrolyte film and gold for

Substance concentration of 0%. The cathode film is produced under constant load. The film thickness is

the output voltage drops within 12 hours 2200, 2598 or 878 A.

the by 0.018 V. Between the terminal post 126 of the anode film

The performance characteristic of this cell is in and the terminal post 166 of the cathode film becomes F i g. 8, in which the relationship between the 50 measured an open circuit voltage of 0.5V. After pole voltage of the power source and the output the connection of a load resistance of current strength for a change in the load 1.0-10 ⁹ ohms to the terminal poles of the films is obtained resistance of 10 ¹⁰ to 0 ohms is shown when you are in an atmosphere with a Oxygen content The power source is located in an atmosphere with an oxygen content of 21% (a pure nitrogen atmosphere) , 7 x 10- "A gives.
Resistance of the power source about 2.8 - 10 ⁸ ohms. If the power source is in an atmosphere with, and that the power source is placed with respect to the oxygen content of 21%, the maximum permissible output current strength itself is kept at the same Load resistance limits. At an output current of about 60 an output voltage of 0.40 V, that of a working 1.8 · 10 ~ ⁹ A, the output voltage drops to zero. Current strength of 0.40 · 10 ~ ⁹ A corresponds, that is to say that such a self-limiting characteristic is one and a half times the working current strength which is obtained in biomedical electronics, where of particular value for applications such as in an oxygen concentration of 0 ° / o It is desirable, with constant load, to have a power source available where the output voltage drops by 0.015 V over the course of 12 hours.
Current supply above a certain maximum The power characteristic of this cell is ceased in amperage without being shown a Fig. 10 in which the relationship between current regulators needs to be used. the pole voltage of the power source and the output

do

Amperage when changing the load resistance and gold produced for the cathode film The film is specified from 10 ^M to 0 Ohm if the thickness is 4320, 8635 or 2015 A,
Power source in an atmosphere with an acidic intermediate terminal 126 of the anode film

material content of 21 Vo is located. From this diagram and the connection pole 166 of the cathode film it can be seen that the effective internal resistance of the S is measured at an open circuit voltage of 0.5 V. According to the power source is about 3.0 · 10 ⁸ ohms and the output current strength obtained by connecting a load resistor from the power source is limited to the maximum permissible 1.0 · 10 »ohms at the terminal poles of the films, an output voltage of 0.15 V is limited that one

At an output current strength of approximately working current strength of 1.5 · 10 ~ ^Μ Α corresponds to 1.6-10 " ⁹ A, the output voltage drops to zero. If the load is constant, the output voltage drops

In view of the very thin film thickness, which decreases by 0.018 V within 12 hours.
These and other performance characteristics of the

The device can be easily built in miniature battery are shown in Fig. 11, in which the construction and micro-miniature size. Therefore, one can draw between the terminal voltage of the battery and easily power sources of suitable size for the output current intensity when changing the above mentioned and other ^{limited application purposes specified with regard to the space load resistance of 10 10} to 0 ohms after the film is open. that produce the effec vapor method. Since the cell does not contain any liquid internal resistance of the battery, dangerous components that splash around, is between 2.5-10 ⁹ ohms and that the battery burns itself or experiences shock caused power in relation to the maximum permissible output current deviations could give rise to, are themselves limited. With an output current strength of current sources manufactured ^{according to the invention for approximately 2.0-10 "10} A, the output voltage drops for purposes that require a robust construction. Such a self-limiting characteristic is particularly important for purposes of application

For the third of the above-mentioned application as within the meaning of the invention, such as. B. in the biomedical according to the invention, it is necessary that niche electronics, where it may be desirable, the cell works as a battery without it being too Lei- to have a battery available, whose Stromstungsabänder due to changes in supply above a previously determined maximum of the oxygen concentration of the environment comes current strength ceases without one having to use a current in this case the cell according to the invention 30 regulator needs to be operated,
Enclosed in a housing impermeable to oxygen. Preferably the oxygen from Example 11
Anode, the cathode and the electrolyte according to the

Assembly evacuated, or assembly a battery of the type shown in FIG. 1 to 3, the construction shown follows in an oxygen-free environment. Then 35 art is enclosed in an anode film impermeable to oxygen, using bismuth for the aggregate, and praseodymium fluoride for the electrolyte housing. For example, the film and gold can be made for the cathode film. The film 18 and the carrier 10 in FIG. 1 such a film thickness are 3174, 2744 and 804 A, respectively.
Form housing if they are made of materials such as silicon dioxide, between the terminal pole 12 b of the anode film

Tantalum oxide, aluminum oxide or silicon oxide, 40 and the terminal post 166 of the cathode film will stand. Because with this type of application as a battery, an open circuit voltage of 0.5 V is measured. After no oxygen anions are contained in the cell, by connecting a load resistor, the cell anode can consist of a metal which forms 1.0 · 10 ⁹ ohms at the terminal poles of the films, while the others have an output voltage of 0, 25 V, which corresponds to an application of the anode metal resistant 45 working current strength of 2.5 · 10 ~ ^{10 A.} Must form when oxides and fluorides. constant load decreases the output voltage

For this type of application as a battery, it is also 0.027 V over the course of 12 hours.
This and other performance characteristics of the

works depending on an external power source. Batteries are shown in Fig. 12, in which the anode and cathode of the cell consist in the relationship between the terminal voltage of the battery and in this case of dissimilar metals, the output amperage when changing the range of the metals ^{load resistance of 10 10} to 0 ohms are shown far apart from one another, with the anode metal having a lower value. From this diagram it can be seen that the work function has as the cathode metal, so that the tive internal resistance of the battery is approximately a potential difference between the electrical 55 1.1 · 10 ⁹ ohms and that the battery develops in the cell. with reference to the maximum permissible output current

Batteries built according to the invention show a self-limited. In the case of an output current intensity of the working characteristic, at which the voltage between the anode is approximately 5.0 10 " ¹⁰ A, the output voltage drops to and the voltage between the cathode drops to zero.

decreases when the external load resistance is 60 Example 12

falls below a certain level, as it is in the subsequent

Examples are described in detail. A battery of the type shown in FIG. 1 to 3 shown construction

art is used with bismuth for the anodei film, neodymium

Example 10 fluoride for the electrolyte film and gold for the cable

65 method film produced. The film thickness is 2200,

A battery of the type shown in FIG. 1 to 3 shown construction 2598 or 878 A.

art is made using bismuth for the intermediate terminal 126 of the anode filuis

Anode film, lanthanum fluoride for the electrolyte film and the connection terminal 16 6 of the cathode film

an open circuit voltage of 0.5 V was measured. After connecting a load resistor of M) · 10 «ohms to the connection poles of the electrode films, an output voltage of 0.27 V is obtained, which ^{corresponds to an operating current of 2.7 · ΙΟ" 10} Α. With constant load, the output voltage increases in the course of 12 hours by 0.015 V.

These and other performance characteristics of the Battery result from Fig. 13, in which the loading

Draw between the pole voltage of the battery and the output current when the load resistance changes from 10 ¹⁰ to 0 ohms; This diagram shows that the dei tive internal resistance of the battery is about 1.0 - K and that the battery is self-limiting with regard to ζ maximum permissible output current. At an output current of ¹⁰ A 6,0-10- the Ausgangsspannuni nuu decreases.

In addition 5 sheets of drawings

Claims (4)

Patent claims: 1. Electrochemical cell with a noble metal cathode, an anode and one with them in contact fluoride solid electrolytes, characterized in that the Electrolyte (14) made of a solid rare earth fluoride in the form of a thin foil and the The anode (12) consists of a metal that forms permanent fluorides 2. Electrochemical cell according to claim 1, characterized in that the electrolyte (14) made of lanthanum fluoride, praseodymium fluoride or neodymium fluoride consists. 3. Electrochemical cell according to claim 1, characterized in that the anode (12) consists of a metal that also forms permanent oxides. 4. Electrochemical cell according to claim 3, characterized in that the anode (12) and the cathode (16) consist of metals with such work functions that between the Electrodes forms an open circuit potential difference of at least 0.2 V.