Reversible Zn/polymer heterogeneous anode

Abstract

Abstract Commercialization of Zn‐metal anodes with low cost and high theoretical capacity is hindered by the poor reversibility caused by dendrites growth, side reactions, and the slow Zn2+‐transport and reaction kinetics. Herein, a reversible heterogeneous electrode of Zn‐nanocrystallites/polyvinyl‐phosphonic acrylamide (Zn/PPAm) with fast electrochemical kinetics is designed for the first time: phosphonic acid groups with strong polarity and chelation effect ensure structural reversibility and stability of the three‐dimensional Zn‐storage‐host PPAm network and the Zn/PPAm hybrid; hydrophobic carbon chains suppress side reactions such as hydrogen evolution and corrosion; weak electron‐donating amide groups constitute Zn2+‐transport channels and promote “desolvation” and “solvation” effects of Zn2+ by dragging the PPAm network on the Zn‐metal surface to compress/stretch during Zn plating/stripping, respectively; and the heterostructure and Zn nanocrystallites suppress dendrite growth and enhance electrochemical reactivity, respectively. Thus, the Zn/PPAm electrode shows cycle reversibility of over 6000 h with a hysteresis voltage as low as 31 mV in symmetrical cells and excellent durability and flexibility in fiber‐shaped batteries.

Keywords

• dendrite‐free
• electrode process kinetics
• fiber‐shaped battery
• reversible metal/polymer heterostructure
• Zn‐metal anode