Biomass Chitin Nanofiber Separators Proactively Stabilizing Zinc Anodes for Dendrite‐Free Aqueous Zinc‐Ion Batteries

Abstract Aqueous zinc‐ion batteries (ZIBs) have generated extensive research attention for stationary energy storage, due to their advantaged superiority in terms of inherent safety, low cost, and eco‐friendliness. However, uncontrollable dendrite growth and side reactions of the Zn anode affect the cycle life of ZIBs. Conventional separators are almost ineffective in inhibiting these issues. Herein, a chitin nanofiber membrane separator is developed to tackle these issues via a simple, low‐cost, and scalable strategy. The obtained separator exhibits abundant zincophilic functional groups, homogeneous nanopores, and excellent mechanical properties, which facilitate the desolvation of hydrated Zn 2+ ions, improve the Zn 2+ transference number, and homogenize the ion flux, simultaneously. Moreover, the separator can also reduce the deposition barrier, and accelerate Zn 2+ deposition kinetics. Therefore, Zn dendrites and harmful side reactions are effectively and synchronously suppressed, enabling the assembled ZIBs with an ultralong cycle life and good rate capability. Impressively, the assembled Zn‐MnO 2 pouch cell exhibits excellent stability and safety under various external damages. The above highlights mark a significant step toward the practical application of ZIBs.