Reconstructing Solvation Structure by Steric Hindrance-Coordination Push-Pull of Dipolymer-H2O-Zn2+ toward Long-life Aqueous Zinc-Metal Batteries.

Abstract

Aqueous zinc-metal batteries are prospective energy storge devices due to their intrinsically high safety and cost effectiveness. Yet, uneven deposition of zinc ions in electrochemical reduction and side reactions at the anode interface significantly hinder their development and application. Here, we propose a solvation-interface attenuation strategy enabled by a frustrated tertiary amine amphiphilic dipolymer electrolyte additive. The configuration of superhydrophilic segments with covalently bonded lipophilic spacers enables coupled steric hindrance/coordination, which establishes a balanced push-pull dynamic of dipolymer-H2O-Zn2+. Such interplay reconstructs the solvation structure of Zn2+ and allows the formation of a stable dipolymer-inorganic hybrid solid electrolyte interface (SEI) layer. This SEI layer effectively shields the zinc-metal anode from water and anions, significantly reducing side reactions. In addition, the dipolymer adsorbed at the zinc-metal anode interface regulates the interfacial electrochemical reduction kinetics and ensures uniform zinc deposition. As a result, the Zn-Zn symmetric cells with dipolymer-containing electrolyte exhibit remarkable cycling stability exceeding 5800 h (242 days). The Zn-NVO batteries and Zn-AC hybrid ion supercapacitors also deliver stable cycling for up to 1440 h (60 days) with high-capacity retention over 80%. This research demonstrates the potential to facilitate the development and commercialization of zinc-based energy storage devices.