Covalent-organic-frameworks derived N-doped porous carbon materials as anode for superior long-life cycling lithium and sodium ion batteries

N-doped porous carbon materials (NPCs) were prepared by the carbonization of covalent-organic frameworks as precursors and used as anodes for lithium and sodium ion batteries (LIBs and SIBs) for the first time. The morphology, structure and electrochemical performance were characterized and evaluated by field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, nitrogen adsorption and desorption isotherms, galvanostatic charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy, respectively. The NPCs not only show high maximum reversible charge capacities of 488 mAh g⁻¹ at 100 mA g⁻¹ (LIBs) and 237.7 mAh g⁻¹ at 50 mA g⁻¹ (SIBs) after 100 cycles, but also deliver high reversible charge capacities of 143 mAh g⁻¹ at 5 A g⁻¹ (LIBs) and 88.8 mAh g⁻¹ at 2.5 A g⁻¹ (SIBs) and excellent rate performance. Moreover, superior long-life cycling stability is observed for 5000 cycles even at a very high current density of 5 A g⁻¹ for LIBs and 2.5 A g⁻¹ for SIBs. The excellent electrochemical performance of NPCs with superior reversible capacity, good rate performance, and long-life cycling stability is attributed to their N doping, high specific surface area and porous structure with large interlayer distance.