Zn anode with flexible β-PVDF coating for aqueous Zn-ion batteries with long cycle life

Aqueous zinc ion batteries (AZIBs) have gained significant attention as a viable alternative for power storage systems due to their desirable properties, including low cost, low environmental impact, and a high specific capacity of 820 mAh g(-1). Nevertheless, their commercial applicability is deterred by issues such as the formation of protrusions and parasitic reactions that can severely damage the cell. In this study, the Zn anode was coated with a thin protective layer of highly polar beta-phase poly(vinylidene difluoride) (beta-PVDF) via a simple spin coating process. The resilient and robust beta-PVDF layer regulated the Zn stripping/plating process and also inhibited corrosion. The resulting beta-PVDF-coated Zn anode (beta-PVDF@Zn) exhibited superior performance compared to that of bare Zn metal and alpha-PVDF@Zn, with a low overpotential of 40 mV for 2000 h of operation in a symmetric cell test. Furthermore, beta-PVDF prolonged the life span of a full cell to 4000 cycles with remarkable cyclic stability. This study provides a facile yet promising strategy to achieve a dendrite-free metal Zn anode.

Automated summary

This study successfully enhanced the performance of aqueous zinc ion batteries by coating the Zn anode with a thin protective layer of beta-PVDF, resulting in reduced overpotential and improved cyclic stability.