PNNL

Abstract

Aqueous Zn-based electrochemical technologies hold promises for large-scale energy storage applications, yet challenges persist in the unsatisfied Zn reversibility arising from unstable Zn/electrolyte interface. Here, we employ molecular interface engineering using amphiphilic Pluronic triblock copolymers as electrolyte additives to stabilize Zn anodes. With a balanced hydrophilic-hydrophobic nature, Pluronic F127 adsorbed on Zn surface constructs a hydrodynamic interphase, where the hydrophobic PPO center shields the Zn surface from water-induced side reactions, while PEO side blocks guide the homogeneous Zn2+ redistribution. Additionally, F127 contributes to Zn2+ solvation structure to weaken the water activity at the interfacial region. As a result, F127 additive enables cycling durability over 9300 and 3100 h at 1 and 5 mA cm-2, respectively, and a considerable cyclability with high-capacity retention across a wide current density range in Zn||VO2 full cells. This study highlights the potential of amphiphilic block copolymers in stabilizing metallic anode interfaces in aqueous electrolytes.