Pasted zinc electrode for rechargeable nickel-zinc batteries

摘要

Active material for a negative electrode of a rechargeable zinc alkaline electrochemical cell is made with zinc metal particles coated with tin and/or lead. The zinc particles may be coated by adding lead and tin salts to a slurry containing zinc particles, a thickening agent and water. The remaining zinc electrode constituents such as zinc oxide (ZnO), bismuth oxide (Bi2O3), a dispersing agent, and a binding agent such as Teflon are then added. The resulting slurry/paste has a stable viscosity and is easy to work with during manufacture of the zinc electrode. Further, the zinc electrode is much less prone to gassing when cobalt is present in the electrolyte. Cells manufactured from electrodes produced in accordance with this invention exhibit much less hydrogen gassing, by as much as 60-80%, than conventional cells. The cycle life and shelf life of the cells is also enhanced, as the zinc conductive matrix remains intact and shelf discharge is reduced.

主权项

1. A method of making a zinc negative electrode, the method comprising:
(a) forming a coating consisting essentially of tin on zinc alloy particles; (b) forming a paste comprising the coated zinc alloy particles, zinc oxide, bismuth oxide, and a binding agent; and (c) incorporating the paste into a zinc electrode, wherein the tin comprises less than about 1% by weight of the paste and, wherein the zinc alloy particles comprise an alloy of zinc with an alloying element selected from the group consisting of bismuth, indium, and combinations thereof, and wherein the zinc alloy particles are less than about 100 micrometers in size.