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

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.