Silk Fibroin Coating Enables Dendrite‐free Zinc Anode for Long‐Life Aqueous Zinc‐Ion Batteries

Abstract Due to the advantages of the low cost of Zn and the safety of aqueous electrolytes, the aqueous Zn ion battery (AZIB) is expected to become the next‐generation battery after lithium‐ion batteries. However, the problems of Zn anode dendrite growth, self‐corrosion, and passivation in AZIBs lead to short cycle life and short circuit of the battery. In this work, uniform and stable Silk II‐silk fibroin (Silk II‐SF) coating was prepared on the surface of Zn anode by a simple method. Experiments showed that the SF coating could prevent dendritic growth and hydrogen evolution corrosion. Therefore, symmetric cells using Silk II‐SF@Zn anode achieved a cycle life over 3300 and 1500 h at current densities of 10 and 20 mA cm −2 , respectively. Using Silk II‐SF coating to protect Zn anode is a simple and effective strategy to realize dendrite‐free Zn anode and long‐cycle‐life AZIBs.