Superabsorbent starch protective layer modulates zinc anode interface for long-life aqueous zinc ion batteries

Aqueous zinc ion batteries (AZIBs) have attracted much attention for their safety, low cost and high theoretical capacity. Nevertheless, Zn dendrites and the adverse reactions such as corrosion, hydrogen evolution and passivation on the anode affect the cycle life and stability of AZIBs. Herein, superabsorbent starch (SS) was employed on Zn foil to form an artificial interface protection layer, which inhibited the formation of dendrites by guiding the uniform deposition of Zn²⁺. SS with a large amount of oxygen-containing functional group is superabsorbent, which can attract the active water around the hydrated Zn²⁺, promoting the desolvation process of the hydrated Zn²⁺ and significantly inhibiting the occurrence of hydrogen evolution reaction. In addition, the inherent pore structure of the SS artificial interfacial layer can induce uniform nucleation of Zn²⁺ and inhibit the dendrites growth. Moreover, compared to bare Zn//MnO₂ cell (44.1 %), the capacity retention of Zn@SS//MnO₂ cell remained as high as 87.8 % after 1000 cycles at 1.5 A g^-1. The simple method provided a new method for the rapid development of AZIBs.