Corrosion-resistant shape-programmable Zn-I2 battery

Abstract

Zinc-iodine (Zn-I-2) 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-I-2 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-I-2 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-I-2 batteries.