Anode Current Collector for Aqueous Zinc-ion Batteries: Issues and Design Strategies

Aqueous zinc ion batteries possess the characteristics of cost-effectiveness, environmental benignancy, intrinsic safety, and relatively high energy density, and are promising to be used in large-scale electrochemical energy storage devices. However, the current commercial zinc foil anode is considerably excessive compared with cathode active materials, which significantly decreases the energy density of the battery. And there are serious problems of anode perforation, tab falling off and so on. Loading zinc on current collector as anode is effective to improve depth of discharge and avoid the electrode perforation. Nevertheless, the zinc dendrites and side reactions are prone to generate at the current collector interface, and they seriously affect the cycle life of the battery. In this review, the causes of zinc dendrites and side reactions and their influence on the electrochemical performance of zinc anode are analyzed, and the design ideas of the zinc anode current collectors are summarized from two aspects of composition selection and structure construction, including the selection of zincophilic materials, the design of preferred-orientation substrates and the construction of three-dimensional current collector structures. Designing an appropriate current collector can effectively regulate the plating and stripping behavior of zinc metal and promote the practical application of aqueous zinc ion batteries.