Synergistically regulating the separator pore structure and surface property toward dendrite-free and high-performance aqueous zinc-ion batteries.

As an emerging electrochemical device, aqueous zinc-ion batteries (ZIBs) present promising potential in safe and large-scale energy storage. However, the large pores of commercial glass fiber (GF) separators result in uneven Zn ion flux, leading to severe dendrite growth issues of Zn metal anodes. Herein, we integrated a multifunctional layer on the GF separator that can synergistically regulate the pore feature and surface property of commercial GF separators. Such modification layer, composed of nanocellulose and SiO nanoparticles, exhibited uniform nanoporous structure and abundant negatively charged polar functional groups. These features allow regulating the distribution of Zn ions at the separator-anode interface, facilitating stable and uniform Zn nucleation and growth. Moreover, the electrostatic interaction between the negatively charged functional groups and Zn ions enhanced the Zn ion transport kinetics, preventing the Zn dendrites formation and adverse reactions. Consequently, the modified electrolyte-filled GF separator showed an increased Zn ion transference number of 0.65. The symmetric Zn//Zn batteries utilizing such a separator achieved an impressive cycling life of 500 h at a high current density/capacity of 10 mA cm/4 mAh cm, nearly nine times longer than the battery using the unmodified GF separator (<55 h). The superior electrochemical performance was verified in both Zn//AC and Zn//LiMnO full battery evaluations. This work presents a novel synergistic modification strategy for developing advanced separators for aqueous ZIBs.