Highly Reversible and Dendrite-Free Zinc Anodes Enabled by PEDOT Nanowire Interfacial Layers for Aqueous Zinc-Ion Batteries.

ABSTRACT

The aqueous zinc-ion batteries (ZIBs) have gained increasing attention because of their high specific capacity, low cost, and good safety. However, side reactions, hydrogen evolution reaction, and uncontrolled zinc dendrites accompanying the Zn metal anodes have impeded the applications of ZIBs in grid-scale energy storage. Herein, the poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires as an interfacial layer on the Zn anode (Zn-PEDOT) are reported to address the above issues. Our experimental results and density functional theory simulation reveal that the interactions between the Zn2+ and S atoms in thiophene rings of PEDOT not only facilitate the desolvation of hydrated Zn2+ but also can regulate the diffusion of Zn2+ along the thiophene molecular chains and induce the dendrite-free deposition of Zn along the (002) surface. Consequently, the Zn||Cu-PEDOT half-cell exhibits highly reversible plating/stripping behavior with an average Coulombic efficiency of 99.7% over 2500 cycles at 1 mA cm-2 and a capacity of 0.5 mAh cm-2. A symmetric Zn-PEDOT cell can steadily operate over 1100 h at 1 mA cm-2 (1 mAh cm-2) and 470 h at 10 mA cm-2 (2 mAh cm-2), outperforming the counterpart bare Zn anodes. Besides, a Zn-PEDOT||V2O5 full cell could deliver a specific capacity of 280 mAh g-1 at 1 A g-1 and exhibits a decent cycling stability, which are much superior to the bare Zn||V2O5 cell. Our results demonstrate that PEDOT nanowires are one of the promising interfacial layers for dendrite-free aqueous ZIBs.