Nitrogen-doped carbon coated zinc as powder-based anode with PVA-gel electrolyte enhancing cycling performance for zinc-ion batteries

Abstract

Zn-powder based anodes are considered as candidates for Zn-based batteries in practical industrial applications in terms of cost, large-scale processing, versatility and tunability. However, Zn-P-based anodes suffer from even more severe side effects including corrosion, passivation, and uncontrolled dendrite growth. Herein, we successfully fabricated nitrogen-doped carbon coating layer on Zn particles (Zn-NC) as anode material for more homogeneous Zn deposition by inducing more zincophilic site on N-doped carbon layers and enhanced electrical connection with carbon networks on Zn-NC particle surface. Nevertheless, metallic Zn deposited on Zn-NC surface still suffers from unavoidable side effects with continuous cycling, even though the dendrite growth was suppressed. It is worth mentioned that PVA-gel electrolyte greatly improves the cycling performance of Zn-NC with limited water content, which can alleviate side reactions. Experiments and simulations address the importance of NC layers with higher electricity, chemical stability, and zincophilic property, as well as the role that PVA-gel electrolyte plays for the further improved cycling performance. Zn-NC with PVA-gel electrolyte achieves ultra-long cycling hours with over 3500 h at 1 mA cm−2 and 850 h at 5 mA cm−2 in symmetrical cells. This study provides a promising pathway and in-depth mechanistic analysis for Zn-powder based anode in versatile applications especially for flexible energy-storage devices.