Lead dioxide-zinc rechargeable-type cell and battery and electrolyte therefor

Abstract

A lead dioxide-zinc rechargeable-type cell comprises at least one positive lead dioxide plate, at least one negative amalgamated zinc metal plate spaced from said positive plate and parallelly confronted thereto, both plates being permanently submerged in an aqueous acid electrolyte containing soluble zinc salts, a zinc surface-controlling agent, an electrolyte conductivity-correcting agent and an amalgamating agent to prevent formation of localized cells or electrolytic pairs on the zinc plate during discharge. An electrolyte suitable to be used in a lead dioxide-zinc rechargeable-type cell comprises an aqueous acid solution of a zinc salt, aluminum sulfate as the zinc surface-controlling agent, sodium sulfate as the electrolyte conductivity-correcting agent, mercuric sulfate as the amalgamating agent and sulfuric acid as an aggressive agent which also acts to minimize the "treeing" of the anodic surfaces. More particularly an electrolyte to be used in a lead dioxide-zinc rechargeable-type cell comprises from 1 to 5 g/l of zinc sulfate, 25 to 75 g/l of sodium sulfate, 25 to 75 g/l of aluminum sulfate, 2 to 8 g/l of mercuric sulfate and 250 to 500 g/l sulfuric acid, the remainder being water. Preferably the electrolyte may additionally contain 10 to 30 g/l of a suitable gum such as dextrin to improve the physical structure of the zinc deposited, and 5 to 15 g/l of dibutyl amine as a corrosion inhibitor.

Dependencies are inferred from the claim text.