Max-planck-gesellschaft Zur F&#xf6;rderung Der Wissenschaften E. V.

Schuco International Kg

Drager Ag

Werner Weppner

Albrecht Rabenau

Peter Hartwig

Winfried Wichelhaus

Klaus-Dieter Kreuer

Helmut Schubert

Gerhard-Ludwig Schlechtriemen

Arnold Van Zyl

Gerhard Hotzel

Michael F Bell

Rolf Hartmann

Volker Leonhard

Gunter Schafer

Wing F Chu

Ervin Hartmann

Jun Liu

Wayne Worrell

Gertraud Ganson

The present invention provides a process for the production of a K- or Rb-.beta.'- or -.beta.-aluminum oxide powder preparation, wherein a cubic densely packed aluminum oxide (.gamma.-aluminum oxide) or a precursor thereof is subjected to attrition together with a doping material or a precursor thereof, the so obtained mixture is calcined in an oxygen-containing atmosphere, potassium oxide or rubidium oxide or a precursor of these compounds is added to the calcination product obtained, the mixture is subjected to attrition and then calcined in an oxygen-containing atmosphere at a temperature greater than 900.degree. C. The present invention also provides a process for the production of a ceramic formed body in which a powder obtained by the above process is converted by attrition, isostatic pressing and sintering into a ceramic formed body. Such a ceramic formed body can be used as an ion conductor.

Process for the production of K- or Rb-.beta.'- or -.beta.- aluminum

The invention concerns as amperometric gas sensor for the selective deteration with high accuracy of a gas partial pressures. Such a gas sensor includes a solid electrolyte and inert electrodes. The solid electrolyte, contained in the sensor, is selected in such a way that when an electrical current or voltage is applied, ions contained in the electrolyte form a reaction product with the gas to be determined in a secondary equilibrium reaction and with generation of an electrically measurable signal. Preferred solid electrolytes are Na.sup.+ -.beta.' aluminum oxide, NASICON, cubic stabilized zirconium oxide and polycrystals of tetragonal zirconium oxide. A method for the selective determination of gases using such electrodes also is described. Preferably an electrical current or voltage source shall be used which feeds a periodic, especially a sawtooth or sinusoidal signal, to the solid electrolyte, as a result of which the formed reaction product is decomposed to the same extent it was previously built up.

Amperometric gas sensor to selectively determine the partial pressures

An electrochromic system. It comprises layers of solid/materials deposited on glass or another substrate. The solids function in an atmosphere that can be dry. One layer is preferably Li.sub.3 AlF.sub.6 and conducts positive lithium ions. Another layer is a counterelectrode. The counterelectrode is improved to the extent that it can reversibly accept ions from and donate them to the ion conductor while remaining extensively transparent. The counterelectrode can be Li.sub.x TiO.sub.y, (Li.sub.2 O).sub.m (WO.sub.3).sub.n (Sb.sub.2 O.sub.3), or (Li.sub.2 O).sub.m (WO.sub.3).sub.n (CeO.sub.2).sub.o.

Electrochromic system

The present invention provides an electrochromic device which is especially suitable as a window, mirror or display element, characterized by a multi-layer construction with at least one layer, enclosed between two coated electrodes, of a material which is either ionically- or mixed ionically- and electronically-conductive, whereby at least one of the two electrode layers consists of transparent material and the ionically- or ionically- and electronically-conductive material is at least so long transparent as no excitation takes place by the application of voltage via the electrodes.

Electrochromic device with ionically or mixed ionically-electronically

A solid electrode in an electrolytic cell for rapid incorporation and exclusion of ions wandering to and from the electrode by way of an electrolyte with a minimum of voltage loss, in particular for a fuel cell, a high-performance battery, an electrochrome sign display unit or an electro-chemical storage element. The electrode comprises a structure having a higher electrical conductivity for electrons or holes than for the ions, and wherein the concentration of the electrons or holes movable within said electrode is lower than the concentration of the ions movable within the electrode.

Solid electrode in an electrolytic cell

The present invention provides a mixed conducting body, wherein it consists f 98 to 25 mol % of cubic or tetragonal zirconium dioxide, 1.5 to 25 mol % of an oxide stabilizing the zirconium dioxide phase and 0.5 to 50 mol % of at least one oxide of a metal of Group Va and VIa of the Periodic System of Elements and/or titanium dioxide, as well as the usual impurities. This body is outstandingly useful as electrode material for oxygen exchange reactions.

Oxidic bodies with ionic and electronic conductivity

A sensor for measuring partial pressures of oxygen with an ion-conducting lid electrolyte of zirconium dioxide as the sensor element, which is arranged between two electrodes for measuring an electrically measurable quantity, is improved so that it is usable at an operating temperature of about 200.degree. C., by providing that the zirconium dioxide as the solid electrolyte is solely in its tetragonal modification and containing an addition of about 2-3 mol % yttrium oxide.

Sensor for measuring partial pressures of gases

A solid state cell for measuring the activity of a component of a mixture using a solid ionic conductor, which is in contact on one side with a reference phase and on the other side with a phase sensitive to the gas component to be determined, is to be improved in such a manner that its detection sensitivity and measuring stability are increased. For this purpose, the gas sensitive phase contains an addition of a substance that increases the electronic conductivity and does not chemically react with the components of the sensitive phase and the gas to be determined.

Solid state cell

The present invention provides a lithium ion conductor, consisting of an ition compound of a lithium halide with an alcohol, an amine or a basic organic heterocyclic nitrogen compound. The present invention also provides a process for the production of this lithium ion conductor, as well as a galvanic element containing it.

Lithium ion conductor

The present invention provides a process for the production of solid in conductor materials based on the following formula:

Process for the production of thermodynamically stable solid ion

A galvanic cell is described, having a metal oxide or metal sulfide electe and a metal electrode, and between them an electrolyte or separator, which is characterized by the fact that it contains as electrolyte a solid proton conductor, namely a zeolite having a proton-containing cation, which has in its crystal lattice passages a phase promoting proton transport.

Galvanic cell comprising solid proton conductor as electrolyte

Solid proton conductors are described, which are based on zeolites having oton-containing cations and having six-member and larger rings as secondary structural groups of the zeolitic structure, and in whose crystal lattice passages a phase is present which promotes proton transport. Their use as separator material and electrolyte for electrochemical cells is also described.

Solid proton conductors and their use

The present invention provides compounds of the general formula:

Ion conductor material

The present invention provides a process for the production of solid ion ductor materials (electrolytes) based on lithium or sodium compounds which stand in thermodynamic equilibrium with their alkali metal and have a high decomposition voltage, wherein two or more binary lithium or sodium compounds with an anion which is formed from one or more elements of the group consisting of nitrogen, phosphorus, arsenic, oxygen, sulphur, selenium, tellurium, hydrogen, fluorine, chlorine, bromine and iodine and which stand in thermodynamic equilibrium with their alkali metal are reacted together in such amounts and for such a period of time that a radiographically phase-pure product is formed. The present invention also provides ion conductor materials based on lithium or sodium compounds, which have the general formula:

A method for measuring the activity of a component of a sample medium using a solid ion conductor having N components wherein N is less than or equal to 3 and having one component which corresponds to the component to be measured is disclosed. The process is carried out by first equilibrating the solid ion conductor with the medium and then with the N-2 adjacent phases of the phase system of the N components of the solid ion conductor. Finally, it is equilibrated with a reference electrode and the voltage between the reference electrode and the medium is measured.

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Stuttgart, Germany

Werner Weppner