Nitrogen-doped carbon composites derived from 7,7,8,8-tetracyanoquinodimethane-based metal–organic frameworks for supercapacitors and lithium-ion batteries

Abstract

In this study, nitrogen-doped carbon composites were prepared by carbonizing 7,7,8,8-tetracyanoquinodimethane (TCNQ)-based metal–organic frameworks (MOFs) under a N₂ atmosphere. The TCNQ ligand and pyrolysis temperature played key roles in the formation of these N-doped carbon composities with various nitrogen contents and species, which can effectively adjust the electrochemical performances of electrode materials. The results showed that the nitrogen-doped carbon composites prepared via carbonization at 650 °C (N-C-650), as the electrode material for supercapacitors, exhibited high capacitance of 223.7 F g⁻¹ at a current density of 1 A g⁻¹, and the specific capacitance retained 73.4% of its initial capacitance after 3000 cycles. Moreover, the nitrogen-doped carbon composites prepared via carbonization at 550 °C (N-C-550), as the anode material for lithium-ion batteries, exhibited a high reversible capacity of 675 mA h g⁻¹ at a rate of 100 mA g⁻¹ and excellent cycling stability (736.8 mA h g⁻¹ after 50 cycles). The good electrochemical performance of the electrode materials was mainly attributed to the high nitrogen content and control over the type of nitrogen species in the nitrogen-doped carbon composites.