Corrosion‐Resistant Shape‐Programmable Zn–I₂ Battery

Abstract

Zinc–iodine (Zn–I2) batteries are promising, low‐cost and safe aqueous rechargeable energy storage devices. An iodide shuttle‐induced corrosion and poor zinc (Zn) stripping/plating often result in a limited battery lifetime, urges the development of multifunctional Zn anodes. To overcome these problems, here multifunctional Zn‐anode is demonstrated with shape‐programmability and uniform Zn morphology along low‐indexed (002) crystal plane, achieved by electrodepositing Zn on nitinol alloy (nickel–titanium, NiTi). It is found that the surface oxide layer on NiTi supports the uniform Zn deposition with densely packed and planar film formation that leads high corrosion resistance, while adopts the shape‐memory function. NiTi‐based device achieves extremely steady performance, benefiting from uniform and planar Zn morphology during cycling, whereas the Zn‐based device short‐circuits due to dendritic development under severe iodide corrosion. It is also demonstrated a flat‐shape‐programmed flexible pouch cell Zn–I2 battery (SP‐ZIB), which performs well in bent mode, recovers its original flat shape at elevated temperature, and shows consistent performance for validated cycles. The shape‐memory function of NiTi makes this Zn–I2 battery advanced by flexibility and shape‐programmable features. This study represents fresh insight for using smart materials as multifunctional features for the next‐generation Zn‐I2 batteries.