Introduction of sidewall CN: a high-temperature-resistant COF for lithium-ion storage

Abstract

Nitrogen-rich covalent organic frameworks (COFs), with their ordered porous structures and tunability, are regarded as promising anode precursors that can be thermally converted into nitrogen-doped carbon materials. Herein, we successfully synthesized a CN modified N-rich COF (COF-HHTP-CN) as an advanced anode precursor for lithium-ion batteries. Since all the N sites were located in CN groups on the sidewall instead of the main chain, COF-HHTP-CN displayed superior structure stability during pyrolysis. Electrochemical analysis demonstrated that NPC₈₀₀ exhibited an optimal lithium storage capacity (436.8 mA h g⁻¹ at 1 A g⁻¹), while NPC₉₀₀ displayed superior lithium storage kinetics. Mechanistic analysis indicated that pyrolysis temperature affects lithium storage performance by altering N species and active sites in the porous carbon materials. This work not only expands the precursor material systems for N-rich porous carbon materials but also reveals the influence of pyrolysis temperature on the electrochemical lithium storage performance of COF-derived N-doped carbon materials.