An Ultra-thin Nonporous Polymer Separator Regulated Na Transfer Toward Dendrite-free Sodium Storage Batteries.

Sodium storage batteries are one of the ever-increasing next-generation large-scale energy storage systems owing to the abundant resources and low cost. However, their viability is severely hampered by dendrite-related hazards on anodes. Herein, a novel ultra-thin (8 μm) exterior-nonporous separator composed with honeycomb-structured fibers was prepared for homogeneous Na deposition and suppressed dendrite penetration. The unhindered ion transmission was greatly benefited from honeycomb-structured fibers with huge electrolyte uptake (376.7%) and the polymer's inherent transport ability. Additionally, polar polymer chains consisting of polyethersulfone and polyvinylidene customize the highly aggregated solvation structure of electrolytes via substantial solvent immobilization, facilitating ion-conductivity-enhanced inorganic-rich solid-electrolyte interphase with remarkably interface endurance. With the reliable mechanical strength of separator, the assembled sodium-ion full cell delivers significantly improved energy density and high safety enabling resisting stable operation under cutting and rolling. The as-prepared separator can further be generalized to lithium-based batteries for which apparent dendrite inhibition and cyclability are accessible, and demonstrates its potential for practical application. This article is protected by copyright. All rights reserved.