Stable Zinc Anodes Enabled by a Zincophilic Polyanionic Hydrogel Layer

Abstract

Abstract The practical application of the Zn‐metal anode for aqueous batteries is greatly restricted by catastrophic dendrite growth, intricate hydrogen evolution, and parasitic surface passivation. Herein, a polyanionic hydrogel film is introduced as a protective layer on the Zn anode with the assistance of a silane coupling agent (denoted as Zn–SHn). The hydrogel framework with zincophilic –SO 3 − functional groups uniformizes the zinc ions flux and transport. Furthermore, such a hydrogel layer chemically bonded on the Zn surface possesses an anti‐catalysis effect, which effectively suppresses both the hydrogen evolution reaction and formation of Zn dendrites. As a result, stable and reversible Zn stripping/plating at various currents and capacities is achieved. A full cell by pairing the Zn–SHn anode with a NaV 3 O 8 ·1.5 H 2 O cathode shows a capacity of around 176 mAh g −1 with a retention around 67% over 4000 cycles at 10 A g −1 . This polyanionic hydrogel film protection strategy paves a new way for future Zn‐anode design and safe aqueous batteries construction.