30 Li+-Accommodating Covalent Organic Frameworks as Ultralong Cyclable High-Capacity Li-Ion Battery Electrodes

Covalent organic frameworks (COFs) have attracted considerable attention as a facile and versatile design platform for advanced energy storage materials owing to their structural diversity, ordered porous structures, and chemical stability. In this study, a redox-active COF (TP-OH-COF) that can accommodate 30 Li+ ions is synthesized for potential use as an ultralong cyclable high-capacity lithium-ion battery electrode material. The TP-OH-COF is synthesized using triformylpholoroglucinol and 2,5-diaminohydroquinone dihydrochloride under solvothermal conditions. The accommodation of such exceptional Li+ ion content in the TP-OH-COF is achieved by alternately tethering redox-active hydroxyl and carbonyl sites on the pore walls. Owing to this unique chemical/structural feature, the TP-OH-COF delivers a high specific capacity of 764.1 mAh g(-1), and capacity retention of 63% after 8000 cycles at a fast current density of 5.0 A g(-1).