Oxidatively pretreated conductive ceramic for zinc anode

Abstract

The invention relates to an additive to the active mass of a zinc anode for an alkaline secondary electrochemical generator. Said additive contains conductive ceramic powder, preferably titanium nitride particles which is exposed to an oxidation pre-treatment prior to the incorporation thereof into the active mass of the anode. Said ceramic powder is used as electronic conduction in the anode active mass and as zincates retention which are produced by generator discharge. In order to use said retentive capacity, the powder is exposed to an oxidation pre-treatment, whereby making it possible to form the binding sites on the surface of ceramic grains. The inventive additive makes it possible, starting from the first cycles of the electrode formation, to form uniform zinc deposits, thereby increasing the service life for the cycling of the zinc anode.

1 . An additive to the active mass of a zinc anode for an alkaline secondary electrochemical generator, comprising a conductive ceramic powder which has undergone an oxidising pre-treatment before being incorporated into the active mass of said electrode.  
     
     
         2 . A conductive ceramic powder used such as an additive to the active mass of a zinc anode for an alkaline secondary electrochemical generator according to  claim 1 , wherein it comprises titanium nitride particles.  
     
     
         3 . A conductive ceramic powder used as an additive to the active mass of a zinc anode for an alkaline secondary electrochemical generator according to  claim 1 , wherein the titanium nitride particles have a particle size essentially less than 10 microns.  
     
     
         4 . A conductive ceramic powder used as an additive to the active mass of a zinc anode for an alkaline secondary electrochemical generator according to  claim 1 , wherein the oxidising treatment was performed in the presence of oxygen.  
     
     
         5 . A conductive ceramic powder used as an additive to the active mass of a zinc anode for an alkaline secondary electrochemical generator according to  claim 1 , wherein the oxidising treatment was performed in air.  
     
     
         6 . A conductive ceramic powder used as an additive to the active mass of a zinc anode for an alkaline secondary electrochemical generator according to  claim 1 , wherein the oxidising treatment was performed at a temperature of between 150° C. and 800° C.  
     
     
         7 . A conductive ceramic powder used as an additive to the active mass of a zinc anode for an alkaline secondary electrochemical generator according to  claim 1 , wherein the oxidising treatment was performed for a period of between five minutes and fifteen hours.  
     
     
         8 . A conductive ceramic powder used as an additive to the active mass of a zinc anode for an alkaline secondary electrochemical generator according to  claim 1 , wherein the titanium nitride was obtained by nitriding titanium.  
     
     
         9 . A conductive ceramic powder used as an additive to the active mass oi a zinc anode for an alkaline secondary electrochemical generator according to  claim 1 , wherein the titanium nitride was obtained by nitriding titanium dioxide.  
     
     
         10 . A conductive ceramic powder used as an additive to the active mass of a zinc anode for an alkaline secondary electrochemical generator according to  claim 1 , wherein the titanium nitride was obtained by a self-propagating thermal reaction from titanium oxide or titanium halides.