A Large-Area Uniform Three-Dimensional Covalent Organic Framework Membrane for Stabilizing Li-Metal Electrodes via Solvation Cages
Zhuozhuo Tang, Jia Chen, Da Zhu, Sheng Li, Yang Yang, Kai Yang, Jianlong Wang, Yaping Tang, Xiangming He, Hong Xu
Abstract
Covalent organic frameworks (COFs), known for their ordered structures, hold promise as ion-conducting materials in cells/batteries. Nevertheless, the rigid cross-linking of porous materials prevents them from being processed into membranes, while composite membranes weaken the material’s conductivity advantage due to phase interruptions. Here, we report a phase-continuous 3-dimensional COF (3D-COF) membrane with a large size of 15 cm × 25 cm, fabricated via in situ interfacial engineering. The COF membranes possessed a non-interpenetrating dia topology that facilitated 3D continuous ionic pathways at the molecular level. Further, the hydroxyl and imine groups on the framework could form Li + -solvation cages, providing the hydrogen-bonding locking sites that facilitate the conversion of the Li-solvates into more readily reducible species. Combined with the dense nanoporous feature, this 3D-COF membrane was found to be very effective in inhibiting Li-dendrites and parasitic reactions and demonstrated a stabilizing effect and good cycling performance in the Li|NMC622 batteries.