A High‐Performance Lithium Metal Battery with Ion‐Selective Nanofluidic Transport in a Conjugated Microporous Polymer Protective Layer

Abstract

Lithium metal is the "holy grail" of anodes, capable of unlocking the full potential of cathodes in next-generation batteries. However, the use of pure lithium anodes faces several challenges in terms of safety, cycle life, and rate capability. Herein, a solution-processable conjugated microporous thermosetting polymer (CMP) is developed. The CMP can be further converted into a large-scale membrane with nanofluidic channels (5-6 Å). These channels can serve as facile and selective Li-ion diffusion pathways on the surfaces of lithium anodes, thereby ensuring stable lithium stripping/plating even at high areal current densities. CMP-modified lithium anodes (CMP-Li) exhibit cycle stability of 2550 h at an areal current density of 20 mA cm^-2 . Furthermore, CMP is readily amenable to solution-processing and spray coating, rendering it highly applicable to continuous roll-to-roll lithium metal treatment processes. Pouch cells with CMP-Li as the anode and LiNi_0.8 Co_0.1 Mn_0.1 O₂ (NCM811) as the cathode exhibits a stable energy density of 400 Wh kg^-1 .