Investigations of a New Family of Alkaline−Fluoride−Carbonate Electrolytes for Zinc/Nickel Oxide Cells

A new family of reduced-alkalinity electrolytes containing fluoride and carbonate anions significantly extends the cycle-life performance of zinc/nickel oxide cells. Various compositions of this family of electrolytes, with a range of KOH concentrations from 2 to 6.9 M, were characterized for zinc/nickel oxide cell cycle-life and power performance, and their conductivities were measured for a range of operating temperatures. The optimum composition for this type of electrolyte based on these criteria was determined to be 3.2−4.5 M KOH with 2 M KF, 2 M K₂CO₃, 0.5 M, LiF (suspension), and saturated ZnO. The cycle-life performance for 1.4Ah sealed cells with the optimum electrolytes is 425−460 cycles to 80% of initial capacity, compared to 75−100 cycles for the conventional highly alkaline electrolyte, 6.8 M:1 M KOH−LiOH, saturated ZnO, a factor of 5 improvement.