Strain-Modulated Deposition Mechanism on a Flexible Zinc Anode

Flexible aqueous zinc-ion batteries (AZIBs) are considered one of the most attractive flexible devices owing to their high theoretical capacity, low cost, and high security. However, the formation of Zn dendrites and the poor flexibility of the Zn material greatly impede the application of wearable AZIBs. Herein, by transferring graphene onto the surface of polyethylene terephthalate-indium tin oxide (PET-ITO-G), a substrate combining excellent flexibility and dendrite suppression ability was prepared. Meanwhile, a quantitative in situ strain application system was proposed to investigate the electrochemical and morphological characteristics of flexible Zn anode interface. The plating/stripping performance of the Zn|PET-ITO-G flexible device was demonstrated under various strains. Subsequent analysis indicated that the origin of its high stability under static bending strain came from the formation of densely packed Zn (101) upon cycling. In addition, PET-ITO-G could quickly recover to Zn (002) after the strain was relieved. A failure model of strain-modulated Zn deposition was proposed based on the formation of surface cracks and distorted surface current distribution. This work identified the main factors that constrained the long cycling life of a flexible metal anode and provided a feasible approach for a systematic study on the influence of in situ strain on flexible batteries.