High-Performance Lithium-Ion Battery and Supercapacitors Using Covalent Organic Frameworks (COFs)/Graphitic Carbon Nitride (g-C3N4)-Derived Hierarchical N-Doped Carbon

Energy storage materials have advanced renewable energy technologies. Herein, we described the one-pot synthesis of covalent organic frameworks (COFs)/graphitic carbon nitride (g-C3N4) nanocomposite. The condensation of melamine and benzene-1,3,5-tricarboxyaldehyde with and without g-C3N4 offered the synthesis of COF and COF/g-C3N4. Furthermore, N-doped carbon and N-doped carbon/g-C3N4 were synthesized via the carbonization of COF and COF/g-C3N4, respectively. The materials i.e., before and after carbonization were used as electrode materials for supercapacitors and lithium-ion batteries (LIBs). They showed specific capacitance of 211, 257.5, 450, and 835.2 F·g–1 for COF, COF/g-C3N4, N-doped carbon, and N-doped carbon/g-C3N4, respectively. Asymmetric supercapacitor device using N-doped carbon/g-C3N4 exhibited good energy (45.97 Wh·kg–1) with high power (659.3 W·kg–1). The N-doped C/g-C3N4 electrode was also applied for LIBs, offering a discharge capacity of 390 mAh·g–1 (at 50 mA·g–1).