Vertical Crystal Plane Matching between AgZn3 (002) and Zn (002) Achieving a Dendrite-Free Zinc Anode

Abstract

Metallic zinc anodes in zinc-ion batteries suffer from problematic Zn dendrite chemistry. Previous works have shown that preferred-orientation crystal planes can help dendrite-free metal anodes. This work reports a nanothickness (≈570 nm) AgZn₃ coating to regulate the Zn growth. First, AgZn₃ @Zn anode avoids the problem, in Ag@Zn anode, that the rate of electrochemical Ag-Zn alloying is slower than that of Zn dendrites growth. Batteries life increased from 112 h (pure Zn) and 932 h (Ag@Zn) to 1360 h (AgZn₃ @Zn) at 2 mA cm^-2 and 1 mAh cm^-2 . Then, plasma sputtering can remove nonconductive ZnO and improve Zn-ion affinity, which brings a longer life for AuZn₃ @Zn (423 h), CuZn₃ @Zn (385 h), and AgZn₃ @Zn (1150 h) than pure Zn (93 h) at 1 mAh cm^-2 . More importantly, AgZn₃ (002) has a high matching with the Zn (002), which can guide ordered Zn epitaxial deposition, thereby achieving dense and dendrite-free Zn growth. This work clearly captures the fascinating structure of the densely stacked Zn layers on the AgZn₃ layer. This strategy not only improves the performance of zinc-ion batteries greatly but will also help one understand the matching mechanism of the (002) vertical crystal plane.

Keywords: AgZn 3 coating; crystal planes; dendrite-free anodes; plasma sputtering; zinc-ion batteries.