“Zincophilic-Hydrophobic” PAN/PMMA Nanofiber Membrane Toward High-Rate Dendrite-Free Zn Anode

Uncontrollable Zn dendrites and side reactions seriously downgrade the cycling stability of the Zn anode, and restrict the commercialization of aqueous zinc ion batteries. Here, PAN-based (PAN, PAN/PMMA) nanofiber membranes with uniform “zincophilic-hydrophobic” sites have been in-situ electrospun on Zn to effectively prevent harmful side reactions and control Zn plating/stripping behavior. The abundant highly-negative functional groups (C≡N and C=O) of PAN/PMMA have strong coordination interactions with Zn²⁺, which can accelerate Zn²⁺ desolvation and increase the Zn²⁺ migration number. Furthermore, the even distribution of zincophilic sites can help create a uniform Zn deposition environment and enable horizontal Zn deposition. Simultaneously, the inherent “hydrophobicity” of the nonpolar carbon skeleton in PAN/PMMA can prevent Zn corrosion and hydrogen evolution reaction (HER) side reactions, thus improving the cycling stability of the Zn anode. As a result, PAN/PMMA@Zn symmetric cells demonstrated remarkable rate performance and long cycling stability, sustaining efficient operation for over 2000 cycles at 10 mA cm^− 2 with a low polarization voltage below 65 mV. This Zn anode modification strategy by in-situ constructed PAN-based nanofiber membrane has the advantages of simple-preparation, one-step membrane construction, binder-free, uniform distribution of functionalized units, which not only provides a specific scheme for developing advanced Zn anode but also lays a certain research foundation for developing “separator-anode” integrated Zn-based batteries.

Graphical Abstract