The inhibition of the spongy electrocrystallization of zinc from doped flowing alkaline zincate solutions

The effects of the presence of additives like lead and tungstate ions in flowing alkaline zincate solutions on suppressing spongy zinc electrogrowth are examined. The results show that the two additives with optimal concentrations in flowing electrolytes can suppress spongy zinc initiation and propagation. And, the two additives can bring about more uniform and compact deposits and, thereby, reduce spongy zinc growth. The influence of lead and tungstate ions on the zinc deposition/dissolution is evaluated by cyclic voltammetry. It also shows that the addition of the two additives is largely a blocking action, and the co-deposition of lead and zinc ions may occur. The performance of the zinc-air flow battery with zinc regeneration electrolysis is determined. It shows that by the addition of 0.6 M Na(2)WO(4) or 10(-4) M to 10(-3) M lead, compact or mixed compact-spongy zinc deposits are created and the favorable charge/discharge performance of the battery is achieved with an energy efficiency of approximately 60%. (C) 2009 Elsevier B.V. All rights reserved.