Hydrophilic silica spheres layer as ions shunt for enhanced Zn metal anode

Aqueous Zn ion batteries (AZIBs) have been widely studied due to their high safety, suitable redox potential and high theoretical capacity. As the most commonly used anode for AZIBs, Zn foil suffers from severe dendrites growth and undesired side reactions, causing battery failure. In this work, a coating layer of stacked SiO2 spheres is designed on a Zn metal surface (SiO2@Zn). The hydrophilic coating layer improves the electrolyte wettability of the Zn anode. Besides, it acts as ions shunt to lead Zn ions evenly plating between the coating layer and the metal anode, avoiding dendrites growth. With electrochemical characterizations and in-situ optical microscopy observations, the electrode presents a stable voltage profile and a long cycling life (2000 h at 0.5 mA cm−2), and the capacity decay in a full cell is significantly alleviated.