Ion Diffusion-Directed Assembly of an Artificial Electronic-Ionic Conductor Layer with Zn-Ion Selective Channels for Highly Reversible Zinc Anodes

Although aqueous zinc-ion batteries have attracted muchattentiondue to their high safety, low cost, and relatively high energy density,their practical applications are severely limited by the uncontrollabledendrite growth and side reactions at the zinc anode. Herein, we designan electronic-ionic conductor artificial layer with Zn-ionselective channels on the Zn surface to regulate the Zn plating/strippingbehavior through a one-step ion diffusion-directed assembly strategyusing the commercially available conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). Significantly, the functional PEDOT:PSS-Zn2+ (PPZ) layer with abundant selective Zn-ion channels worksas both an electron regulator and an ion regulator that could notonly simultaneously uniformize the electrical and Zn2+ concentrationfield on the Zn surface and accelerate the Zn2+ transportkinetics but also block the access of SO4 (2-) and H2O. With such a synergy effect, the PEDOT:PSS-Zn2+-modified Zn anode (2PPZ@Zn) achieves a long lifespan of2400 h of the symmetrical cell at a current density of 3 mA cm(-2) (1 mA h cm(-2)). Additionally, along-term lifespan of 500 h is harvested even at a high current of5 mA cm(-2) with a high capacity of 3 mA h cm(-2). Furthermore, combined with a manganese dioxide cathode,a full cell similarly provides a cycling stability of over 1500 cycleswith 75% capacity retention at a high rate of 10 C (1 C = 308 mA hg(-1)).

Automated summary

In this study, an electronic-ionic conductor artificial layer with Zn-ion selective channels is designed to regulate the Zn plating/stripping behavior. This layer works as both an electron regulator and an ion regulator, unified the electrical and Zn2+ concentration field on the Zn surface and blocking the access of unwanted substances. The modified Zn anode achieves a long lifespan and high capacity, and a full cell with a manganese dioxide cathode shows excellent cycling stability.