Ion–dipole interaction motivated Zn2+ pump and anion repulsion interface enable ultrahigh-rate Zn metal anodes

Abstract

Aqueous Zn–metal batteries are considered promising candidates for next-generation energy storage. However, their reliability, especially under high-rate conditions, is compromised by the poor cycling stability of Zn metal anodes, caused by insufficient Zn²⁺ replenishment owing to concentration gradients at the reaction interface. Herein, we introduce a zinc perfluorovalerate interfacial layer (Zn@PFPA) that serves as a self-expedited Zn²⁺ pump through an in situ organic acid etching route. This distinctive feature ensures rapid and dynamic interfacial replenishment of Zn²⁺ to eliminate the concentration gradients, leading to non-dendritic and highly reversible Zn plating/stripping behaviors, even at elevated rates. Theoretical calculations and experimental results highlight the swift Zn²⁺ transport kinetics driven by ion–dipole interactions, maintaining a steady and homogenous Zn²⁺ flux. Moreover, the high electronegativity and hydrophobic properties of the Zn@PFPA layer further enable charge repulsion of detrimental anions and mitigate free water present at the electrode/electrolyte interface, fundamentally inhibiting the HER and by-product generation. Consequently, the Zn@PFPA electrode displays an outstanding cumulative capacity of 95 000 mA h cm⁻² with a lifespan of 1900 h at an exceptionally high current density of 50 mA cm⁻². Furthermore, its feasibility is also demonstrated by coupling with a high-loading I₂ cathode (∼9.0 mg cm⁻²) to fabricate pouch batteries, achieving impressive 10 000 stable cycles at 10 A g⁻¹.