Interweaved Nanofiber Anode Coating Based on Covalent Organic Frameworks for High-Performance Lithium-Metal Batteries

Abstract

High-rate lithium-metal batteries call for unique interfacial structures of anode with interfacial compatibility, facilitated lithium insertion/extraction and dendrite suppression properties to meet the growing high-rate demand. Here, we develop an interweaved porous coating based on a kind of covalent organic framework (ODH-Cu3-COF) based helical nanofibers through the assembly of non-linear oxalyldihydrazide unit and rigid Cu3 unit. The interweaved helical nanofibers network with well-arranged polar groups (i.e. C=N, -CO-NH- and pyrazole groups) could serve as nuclei sites to achieve fast Li+ insertion/extraction and dendrite suppression in high-rate conditions. Benefiting from the advantages of interface design, the resultant ODH-Cu3-COF modified anode improves the Coulombic efficiency (97.5%, 120 cycles at 5 mA cm-2) and showcases a stable lifespan (1000 h at 2 mA cm-2 and 2 mAh cm-2) in symmetric cell. Moreover, the high-rate property of ODH-Cu3-COF@Li||LFP full cell presents an excellent cycling stability (900 cycles at 5 C) in commercial carbonate electrolyte. Theoretical calculations reveal that lithiophilic ODH-Cu3-COF has high Li affinity to reduce the nucleation barrier and achieve fast desolvation process in interface to promote the lifespan of high-rate lithium-metal batteries.