a battery having a zinc or zinc alloy anode , a metal oxide or hydroxide cathode and an alkaline electrolyte comprising a solution of a salt formed by the reaction of boric acid , phosphoric acid or arsenic acid with an alkali or earth alkali hydroxide present in a sufficient amount to produce a stoichiometric excess of hydroxide to acid in the range of 2 . 5 to 11 . 0 equivalents per liter , and of a soluble alkali or earth or earth alkali fluoride in an amount corresponding to a concentration range of 0 . 01 to 1 . 0 equivalents per liter of total solution .