Modulating Interfacial Zn²⁺ Desolvation and Transport Kinetics through Coordination Interaction toward Stable Anodes...

Aqueous Zn-ion batteries (AZIBs) are promising candidates for grid-scale energy-storage applications, but uneven Zn²⁺ flux distribution and undesirable water-related interfacial side reactions seriously hinder their practical application. Herein, a strategy of regulating the coordination interaction between Zn²⁺ and artificial interphase layers (AILs) to modulate the interfacial Zn²⁺ desolvation/transport behaviors and relieve side reactions for building stable Zn anodes is proposed. By selectively choosing appropriate polymers with different functional groups, it is shown that compared with the strong interaction offered by aryl groups in polystyrene-based AILs, cyano groups in polyacrylonitrile (PAN)-based AILs provide a moderate coordination interaction with Zn²⁺, which not only accelerates interfacial Zn²⁺desolvation kinetics but also enables efficient Zn²⁺ transport within AILs. Moreover, the Zn²⁺ transport kinetics of PAN-based AILs can be further enhanced with the incorporation of an ionic conductor, zinc phosphate (ZP). Because of these advantages, the Zn anodes decorated with the hybrid AILs composed of PAN and ZP can steadily operate for >2000 h at 0.2 mA cm^-2 and >350 h at a high current density of 10 mA cm^-2. This work provides a valuable guideline for selective design of AILs at the molecular level for durable AZIBs.