Rheinisch-westfalisches Elektrizitatswerk Ag

Heinz Peter Fritz

Rainer Huss

Jurgen Besenhardt

Detlef Missol

Jurgen Besenhard

Dietrich Wabner

Gerhard Rauschenbach

An electrode for use in electrolytic processes, e.g. as an energy storage electrode for a lead-dioxide accumulator or storage battery, is produced by subjecting a titanium support to a cleaning operation and subsequently to a surface treatment in a medium which is constituted by a titanium (IV) salt solution. This results in the formation of a titanium (IV) adsorbed layer onto which the lead dioxide active material is anodically deposited. An important characteristic of the invention is that the surface treatment is carried out such that hydrolysis of the titanium (IV) activated surface does not occur and hence the titanium at the surface of the support and the interface between the latter and the lead dioxide active material is in the tetravalent titanium state. The titanium deposit is from a titanium (IV) salt of an inorganic oxy acid, preferably perchloric acid, a salt of an organic acid, or a complex of the titanium (IV) ions with a complex former.

Method of making electrodes for electrolytic purposes

A lead-acid storage cell is operated at a temperature of about 70.degree. C and comprises a positive electrode which, in the charged state, carries an active mass consisting predominantly of lead dioxide, a negative electrode consisting predominantly of lead in the charged condition, and a sulfuric acid electrolyte. To permit the storage cell to operate at the elevated temperature without deterioration, the negative electrode is provided with a sheath permeable to the electrolyte but impermeable to particles released from the negative electrode. The sheath, which may constitute the interelectrode separator, can consist of a nonwoven or woven fabric of glass fiber or a nonwoven or woven fabric of unsubstituted or perhalogenated polyolefin or a layer of ceramic. The electrolyte in the cell is covered by a vaporization-resistant layer consisting of floating solid particles or a liquid which is unaffected by the high operating temperature. The battery or cell can be heated so as to permit its discharge, for example, at the aforementioned optimum temperature of about 70.degree. C.

High-temperature method of operating a lead-acid cell

In making a lead electrode for a lead-acid accumulator or the like, a supporting body of titanium is pickled in a boiling solution of oxalic acid and then adsorptively coated with a titanium (IV) layer in a treatment bath. This treatment is followed by the anodic coating of the titanium body with PbO.sub.2 in an electrolyte containing the ions of lead (II), in the presence of a lead (II) nitrate or a lead (II) salt of an amido, imido, nitrido or fluoro sulfate or phosphate. The treatment bath may be an aqueous solution of an organic titanium salt, the pickling solution, or the electrolyte. If the pickling solution is used for this purpose, the titanium body is anodically connected or the solution is oxygenated. If the electrolyte is utilized, Ti(IV) ions are introduced into that liquid in which the titanium body is immersed for an extended period before closure of the anodizing circuit.

Process for making titanium-supported lead electrode

A primary or secondary electrochemical cell having a negative electrode consisting of a light metal or an alloy predominantly consisting of a light metal (especially lithium), a nonaqueous aprotic preferably organic electrolyte, and a positive electrode which consists at least predominantly of a metal or metalloid which is capable of electrochemically forming an intermetallic compound with the light metal upon cathodic liberation thereof. The positive electrode may consist of, at least in major part, arsenic, antimony or other semimetal, metalloid or semiconductor.

Primary or secondary electrochemical cell

In making an electrode for a lead-acid accumulator or the like, a supporting body of titanium is immersed in a boiling solution of oxalic acid containing the ions of a titanium-oxalato complex. This treatment is followed by anodic coating of the titanium body with PbO.sub.2 in an electrolyte containing the ions of lead (II), in the presence of a lead (II) salt of an amido, imido, nitrido or fluoro sulfate or phosphate at least during a first anodizing stage. The coated electrode may be further immersed in a weakly medium for a prolonged period.

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Munich, Germany

Heinz Peter Fritz