Understanding and Performance of the Zinc Anode Cycling in Aqueous Zinc-Ion Batteries and a Roadmap for the Future

Abstract

By virtue of environmental benignity, inherent safety, and affordable cost of raw materials, aqueous zinc-ion batteries (AZIBs) have witnessed tremendous upheaval in research interest and are considered to have enormous potential for stationary and renewable storage applications. Yet, the high activity of Zn in aqueous electrolytes triggers metal corrosion and hydrogen evolution, which, together with dendrite formation on zinc surface during its electrodeposition, leads to poor Coulombic efficiency and rapid short-circuit failure during cycling. Therefore, to divulge a critical and in-depth understanding of these underlying issues, (electro)chemical behavior of the Zn metal in aqueous electrolytes and corresponding theories are first discussed in this review. This is followed by a thorough discussion of various strategies, categorized based on the intrinsic mechanism, for the suppression of dendrite and parasitic side reactions that are ultimately intertwined. Finally, strategic recommendations are provided as a roadmap to coordinate research and development efforts, and the energy density analyses of a representative AZIB cell is presented to highlight technical and functional needs for the practical development of the technology. This review is expected to provide a comprehensive understanding of the Zn metal anode development for AZIBs and draw attention to pertinent criteria for performance assessment.