Compositions, zinc electrodes, batteries and their methods of manufacture

Abstract

A composition, method of its preparation, and zinc electrodes comprising the composition as the active mass, for use in rechargeable electrochemical cells with enhanced cycle life is described. The electrode active mass comprises a source of electrochemically active zinc and at least one fatty acid or a salt, ester or derivative thereof, or an alkyl sulfonic acid or a salt ester or derivative thereof. The zinc electrode is assumed to exhibit low shape change and decreased dendrite formation compared to known zinc electrodes, resulting in electrochemical cells which have improved capacity retention over a number of charge/discharge cycles.

1 - 87 . (canceled) 
     
     
         88 . A zinc electrode for use in the manufacture of rechargeable cells and batteries comprising as active composition an intimate mixture of: a salt of a fatty acid; and a zinc oxide, zinc hydroxide or mixture thereof. 
     
     
         89 . The electrode as claimed in  claim 88  where the composition further comprises an alkali metal hydroxide. 
     
     
         90 . The electrode as claimed in  claim 89  where the alkali metal hydroxide is present in an amount no less than 0.3 g per 0.1 mole zinc oxide, zinc hydroxide or mixture thereof. 
     
     
         91 . The electrode as claimed in  claim 90  where the alkali metal hydroxide is potassium hydroxide. 
     
     
         92 . The electrode as claimed in  claim 88  where the intimate mixture is formed by precipitation. 
     
     
         93 . The electrode as claimed in  claim 92  where the fatty acid is a C 6 -C 30  fatty acid. 
     
     
         94 . The electrode as claimed in  claim 93  where the fatty acid is a naturally occurring C 12 -C 22  fatty acid. 
     
     
         95 . The electrode as claimed in  claim 94  where the fatty acid is a naturally occurring C 16 -C 20  fatty acid. 
     
     
         96 . The electrode as claimed in  claim 95  where the fatty acid is a metal salt of stearate. 
     
     
         97 . The electrode as claimed in  claim 96  where the fatty acid is zinc stearate. 
     
     
         98 . The electrode as claimed in  claim 96  where the fatty acid is calcium stearate.