Highly (002)-Oriented Zno in Zno-N-C Microflakes Coating Layer for Stable Zinc Anode in Zinc-Air Batteries

Abstract

Rechargeable alkaline zinc-air batteries (ZABs) are widely used in small electronic devices with high theoretical energy density, low cost, and environmentally friendly. However, zinc anode will emerge dendrite growth and corrosion problems during cycling and seriously affect the cycle life of the batteries. Thereby, a new ZnO-N-C microflake was synthesized as a protection layer for zinc anode by hydrothermal methods and subsequent calcination processes in this work. The ZnO with more preferred crystal plane (002) in the ZnO-N-C-600 microflakes can provide uniform charge distribution to induce the uniform deposition of Zn2+. And the strong interaction among each component in the ZnO-N-C can accelerate the electron transport to inhibit the violent growth of dendrites and further improve reversibility of Zn2+ plating/stripping. The ZnO-N-C-600@Zn assembled symmetric battery achieves a stable 800 h cycling with a low overpotential (70 mV) at 0.5 mA cm-2, while the bare zinc symmetric battery has a cycle life of less than 170 h. ZnO-N-C-600@Zn used as anode in alkaline zinc-air batteries shows comparable electrochemical performance. This work provides a broad application prospect for the development of a stable zinc anode for rechargeable zinc-air batteries.

Keywords: ZnO-N-C, microflakes, zinc anode, coating layer, Zinc-air batteries