Phthalocyanine Separator with “Chelation-Relay” Behavior for Homogeneous Zn2+ Flux and Ultra-Stable Aqueous Zinc-Ion Batteries

Abstract

Aqueous zinc-ion batteries present several advantages, including high safety and low cost, however, severe dendrite growth and side reactions at the zinc anode significantly impede their cycle life and efficiency. This study proposes a zinc deposition regulation strategy based on a synergistic "chelation-relay" mechanism, achieved by constructing a phthalocyanine functional layer on the surface of a cellulose separator. The phthalocyanine layer, which is rich in nitrogen coordination centers, effectively chelates Zn2+, reshaping the electrode/electrolyte interface structure and inhibiting side reactions. Its macrocyclic conjugated architecture functions as an "ion relay," facilitating reversible storage and providing ordered migration channels for Zn2+ , thereby alleviating concentration polarization and promoting uniform deposition. COMSOL simulation results demonstrate that this functional layer can homogenize the interfacial electric field and Zn2+ flux, thereby suppressing the "tip effect" associated with dendrite formation. Consequently, stable zinc deposition and stripping over 1000 cycles under conditions of 1 mA cm-2 and 1 mAh cm-2 yield an average coulombic efficiency of 99.1%. Furthermore, the Zn/I2 full cell exhibits a capacity retention rate of 98.83% after 10000 cycles at a discharge rate of 1 A g-1. These findings underscore the potential of phthalocyanine to regulate zinc deposition, contributing to the development of high-performance aqueous zinc-ion batteries.