Anode Optimization Strategies for High-performance Aqueous Zinc-ion Batteries

Abstract

Recent years, various alkali metal ion batteries have been widely studied and gradually applied in modern society.[1–3] However, rising raw material and organic components prices, and the inherent safety hazards of the unstable system have seriously hindered their further application.[4,5] Therefore, it is becoming increasingly important to develop a promising battery to complement or even replace those organ alkali metal-ion batteries. Aqueous zinc-ion batteries are considered as a promising alternative due to their high theoretical capacity, abundant and cheap resources, and the feasibility of aqueous electrolyte systems due to the aqueous stability of zinc metal.[6–8] In recent years, cathode material like manganese oxide,[9,10] vanadium oxide,[11,12] organic molecules,[13–15] etc. and corresponding reaction mechanisms that are well matched to aqueous zinc ion battery systems have been intensively studied. However, the low Coulombic efficiency (CE), zinc dendrites, and unstable zinc deposition problems in zinc anode hinder the further development of zinc ion batteries. At the same time, due to the inability to form a stable protective solid electrolyte interface (SEI) in situ during zinc plating and stripping processes, the complex relationship among zinc anolyte, interface, and zinc host also makes the research on the reaction mechanism of zinc anode more diverse and complicated.[16–18] The current anode optimization methods could be divided into three categories: electrolyte modification,[19,20] zinc anode surface coating,[21,22] and zinc anode structure redesign.[23,24] Herein, we have developed multiple zinc anode optimization strategies to improve the stability of zinc plating/stripping. These strategies have been effectively applied to tune the electrochemical performance of aqueous zinc ion battery for establishing a highly reversibility and long-lived zinc anode.