Beyond solvothermal synthesis: construction of covalent organic frameworks at near-ambient conditions

The development of a novel reaction synthesis method for covalent organic frameworks (COFs) under near-ambient conditions (NAC) is crucial for replacing the traditional solvothermal method and achieving gram-level production. However, to date, most of the reported synthesis methods rely on external devices to facilitate the chemical reactions, and COFs linkages are mainly focused on imine-linked COFs. Here, we report a straightforward NAC method for the synthesis of β-ketoamine linked COFs at 30°C under atmospheric conditions. A series of high crystallinity COFs with different topological structures and functional groups were achieved through this novel method. In addition, the reactions can be conducted in organic or aqueous acid solutions, and reactions on a gram-level scale can be accomplished. As a result, COF-β-KA-CF₃ based solid-state electrolytes (SSEs) exhibited an outstanding lithium-ion conductivity of 6.53 × 10^-4 S cm^-1 at 30°C and demonstrated stable long-cycling performance in solid-state batteries. The simplicity, scalability, and economic viability of the NAC method hold great promise for the exploration of new COFs in the future.