Dendritic Zn Deposition in Zinc-Metal Batteries and Mitigation Strategies

As one of the most promising energy storage technologies, zinc (Zn)-metal batteries (ZMBs) have attracted significant attention due to outstanding properties of Zn, including high energy density (820mAhg(-1)/5855mAhcm(-3)), abundance, low cost, low reactivity, multielectron redox capacity, compatibility with aqueous electrolytes, low equilibrium potential (-0.76V vs SHE), stability, safety, and environmental benignity. Yet, the existence of some major issues such as surface-originated parasitic reactions (e.g., corrosion and H-2 evolution), formation of dead Zn, and oxide passivation leading to capacity loss in ZMBs are hindering their full potential applications. Addressing these challenges requires profound understanding of mechanism of Zn dendrites formation. Therefore, the aim of the current study is to assess some of the latest challenges and advancements concerning ZMBs, with an emphasis on origin and growth mechanism of Zn dendrites. Herein, it is demonstrated that the Zn electrodeposition does not follow a simple reaction/diffusion limited behavior, and other parameters such as surface energy and surface diffusion barrier play great roles on the morphology and microstructure of the deposited Zn. In addition, recent advances to mitigate Zn dendrite issues by applying modifications on the design of electrode, electrolyte, separator and interface are discussed.