Negative electrode formulation for a low toxicity zinc electrode having additives with redox potentials positive to zinc potential

Abstract

A zinc electrode composition is provided for use in low toxicity, high energy density cells having alkaline electrolytes. The zinc electrode comprises zinc oxide, a binder, and from 0.1% up to 10% of a fluoride of an element chosen from the group consisting of silver, gallium, indium, tin, tellurium, lead, bismuth, and combinations thereof. The invention also provides an electrochemical cell having an electrode as noted above. The inventive cell further comprises an electrolyte which contains a mixture of sodium, potassium, and lithium hydroxides, together with boric acid. The excess alkali hydroxide is present in the range of 2.7 to 5M, and the concentration of boric acid is between 0.6 and 1.3 moles per litre.

1 - 4 . (canceled)  
     
     
         5 . An electrochemical cell having comprising: 
 a zinc electrode comprising zinc oxide, a binder, and from between 0.1% up to 10% of a fluoride;    an electrolyte comprising a salt of boric acid in a concentration of between 0.6 and 1.3 moles per liter and excess alkali hydroxide in the range of 2.7 to 5M; and    a nickel electrode.    
     
     
         6 . The electrochemical cell of  claim 5 , wherein excess alkali comprises potassium hydroxide.  
     
     
         7 . The electrochemical cell of  claim 5 , wherein excess alkali comprises sodium hydroxide.  
     
     
         8 . The electrochemical cell of  claim 5 , wherein excess alkali comprises lithium hydroxide.  
     
     
         9 . The electrochemical of a cell of  claim 8 , wherein the lithium hydroxide is present in a concentration of between 0.1 and 3 molar.  
     
     
         10 . The electrochemical of a cell of  claim 5 , wherein the zinc electrode further comprises from 1% up to 10% bismuth oxide.  
     
     
         11 . The electrochemical of a cell of  claim 5 , wherein the fluoride is of an element chosen from the group consisting of silver, gallium, indium, tin, tellurium, lead bismuth, and combinations thereof.