In situ constructing film-coated 3D porous Zn anodes by redox strategy toward dendrite-free aqueous zinc-ion batteries

Aqueous zinc ion batteries (AZIBs) occupy an important position in the future generation of large-scale energy storage, owing to their high theoretical capacity, and inherent safety. However, the inevitable dendrite growth and side reactions of zinc anodes become a serious obstacle for AZIBs in practical applications. Here, a uniform and porous protective layer is fabricated via a facile redox reaction between Iron (III) chloride and Zn metal. The 3D Zn@PVDF electrode not only promotes the orderly deposition of Zn 2+ but also isolates the zinc anode from the electrolyte, thus inhibiting side reactions. As a result, the symmetric cell equipped with a modified Zn anode exhibits a long cycle life over 1700 h at 1 mA cm −2 , and has excellent rate performance. In addition, the full battery with an ammonium vanadate cathode exhibits excellent electrochemical stability, showing a high capacity retention of 77.3% after 1500 cycles at 2 A g −1 . This work presents a simple and reliable interface modification strategy for the protection of zinc anodes. A film-coated 3D porous zinc anode via the spontaneous redox reaction between metallic Zinc and FeCl 3 was designed. This modified zinc anode not only promotes the ordered deposition of Zn 2+ and reduces the formation of zinc dendrites, but also isolates the zinc anode from direct contact with the electrolyte, thereby suppressing the occurrence of side reactions. This provides a simple and reliable interface modification strategy for the protection of zinc anodes. • The film-coated 3D porous Zn anode facilitates uniform Zn 2+ transport. • The protection layer isolates the direct contact between the zinc anode and the electrolyte, inhibiting side reactions. • The 3D Zn@PF-5 symmetric cell achieved a long lifetime of 1500 h at 2 mA cm −2 .