Directional Electron Traction and Selective‐Sieving Effects Enabled by Biomimetic UIO‐66‐NH 2 ‐Assisted Polyimide Electron Sponge for Ultra‐Durable Sodium‐Sulfur Battery

ABSTRACT Severe sodium polysulfides (NaPSs) shuttling and sluggish reaction kinetics substantially hinder the development of room‐temperature sodium‐sulfur (RT/Na‐S) batteries. Herein, a biomimetic uio‐66‐NH 2 ‐assisted polyimide with carbon‐nanotube (uio@PI/CNT) for separator‐modification is proposed. Selective‐sieving effects induced via the inherent PI‐pore segmentation by uio‐66‐NH 2 efficiently inhibit NaPSs shuttling and maintain a uniform Na + flux for homogeneous Na‐deposition. Particularly, imide‐carbonyl and triazine moieties in PI, regarded as “electron sponge” capable of successive electron uptake and supply, exert the directional electron‐traction between external circuit and NaPSs to enable prompt electron‐donation to and electron‐extraction from NaPSs during discharging and charging, thereby remarkably reducing the sulfur‐conversion energy barriers. Integrating with enhanced electron‐conduction via CNT, effective binding with NaPSs, and high‐speed Na + transport mediated via sufficient groups synergistically provided by PI and uio‐66‐NH 2 for retaining active‐specie and timely replenishing reactants to PI catalytic centers, the fast reaction kinetics and highly stable anode are achieved. Consequently, a high reversible capacity (1248 mAh g −1 ) at 1 A g −1 with 96.7% cycling‐retention and an ultralow fading (0.0055%) per cycle even at 2 A g −1 are presented. The catalytic mechanism involving “electron sponge”, with the selective‐sieving effects, imparts a novel direction for exploiting the ultra‐durable sodium‐sulfur batteries.