Ultralight PEDOT Functionalized Separators toward High‐Performance Lithium Metal Anodes

Abstract The practical application of lithium‐metal batteries (LMBs) has been limited by the problems of uncontrolled lithium dendrite growth, resulting in a low Coulombic efficiency (CE) and rapid battery failure. Herein, we develop an ultralight poly(3, 4‐ethylenedioxythiophene) (PEDOT) modifying Celgard polypropylene (PP) separator with a mass loading of 0.08 mg cm 2 by vapor phase polymerization. The increased affinity between the PEDOT/PP separator and electrolyte interface enables homogenous Li + flux. Meanwhile, the lithiophilic thiophene functional groups of PEDOT guide uniform Li nucleation and growth through the formation of Li−S bond. As a result, dendrite‐free Li deposition has been achieved with a high CE of 98.0 % over 150 cycles and flat stable overpotential of ∼90 mV at an ultrahigh rate of 20 mA cm −2 in the symmetric cell. Remarkably, the Li||PEDOT/PP||LiNi 0.8 Co 0.1 Mn 0.1 O 2 full cells demonstrate superior stability up to 500 cycles with a discharge capacity of 119 mAh g −1 at 1 C. This work paves way for modifying separator for high‐performance LMBs.