Regulating the Interfacial Charge Density by Constructing a Novel Zn Anode-Electrolyte Interface for Highly Reversible Zn Anode

Aqueous zinc-ion batteries (AZIBs) have attracted considerable attention. However, due to the uneven distribution of charge density at Zn anode-electrolyte interface, severe dendrites and corrosion are generated during cycling. In this work, a facile and scalable strategy to address the above-mentioned issues has been proposed through regulating the charge density at Zn anode-electrolyte interface. As a proof of concept, amidinothiourea (ATU) with abundant lone-pair electrons is employed as an interfacial charge modifier for Zn anode-electrolyte interface. The uniform and increased interfacial charge distribution on Zn anode-electrolyte interface has been obtained. Moreover, the unique Zn-bond constructed between N atoms and Zn2+ as well as the hydrogen bonds are formed among ATU and Ac- anion/active H2O, which promote the migration and desolvation behavior of Zn2+ at anode-electrolyte interface. Accordingly, at a trace concentration of 0.01 mg mL-1 ATU, these features endow Zn anode with a long cycling life (more than 800 h), and a high average Columbic efficiency (99.52 %) for Zn||Cu batteries. When pairing with I2 cathode, the improved cycling ability (5000 cycles) with capacity retention of 77.9 % is achieved. The fundamental understanding on the regulation of charge density at anode-electrolyte interface can facilitate the development of AZIBs. Thepolar organic molecule amidinothiourea (ATU), as an electrolyte additive, can be stably adsorbed on the surface of zinc metal to construct the zinc anode-electrolyte interface and build new Zn-bond, promoting Zn2+ desolvation and deposition kinetics. Meanwhile, the hydrogen bonding network of the electrolyte can be reconstructed by ATU, which facilitates the migration of cation.+image