Improved reversibility of Zn anodes for rechargeable Zn-air batteries by using alkoxide and acetate ions

• Published in: Electrochimica acta 2016-05, Vol.199, p.164-171
• Main Authors: Lee, Junghye, Hwang, Boyeong, Park, Min-Sik, Kim, Ketack
• Format: Article
• Language: English
• Subjects: Acetates; additive; alcohol; Alkoxides; Formations; Metal air batteries; Rechargeable batteries; Zinc oxide; Zinc-oxygen batteries; Zincates; Zn air battery; ZnO
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2016.03.148

Irreversible formation of ZnO from Zincate ion is effectively suppressed by addition of alcohols, where some hydroxides are replaced with alkoxide ions. [Display omitted] •Alcoholic additives can improve the cycle performance of Zn-air cells.•Irreversible formation of ZnO can be suppressed by forming alkoxide-modified zincates.•Monoalcohol is more effective than polyols for improving the cycle performance. The irreversible formation of zinc oxide (ZnO) in Zn–air batteries is not avoidable. Because of the formation of ZnO, the battery capacity, potential, and coulombic efficiency decrease. The low electrochemical reactivity of ZnO is the main obstacle that interferes with building an electrochemically rechargeable Zn–air battery. In this work, electrolytic additives that suppress the formation of ZnO are studied. The zincate ion (Zn(OH)42−) is an intermediate ion, which transforms into ZnO in basic solutions during the discharge process. Some hydroxide ions in zincate can be replaced with alkoxide and acetate ions; this resulted in a clear improvement of the reversibility of Zn–air batteries. The modification of zincate with alkoxide/acetate suppresses its transformation into ZnO, which results in improved retention of capacity in cycle tests.