Synthesis of Picolylamine-Functionalized Graphene via Fluorographene Chemistry for High-Performance Symmetric Supercapacitors

Graphene-based materials have emerged as promising candidates for supercapacitor electrodes. However, their low energy density and the poor conductivity of commonly used graphene oxide remain critical challenges. In this study, we leveraged fluorographene chemistry to synthesize a graphene derivative functionalized with out-of-plane pyridine rings, covalently attached on graphene’s network (G-Npyr). The resulting material exhibited a specific surface area of 230 m² g^–1 while the removal of fluorine atoms from fluorographene’s lattice substantially restored graphene’s conductivity. As a result, G-Npyr-based electrodes delivered an energy density of 61 Wh kg^–1 at a power density of 907 W kg^–1 and a volumetric energy density of 112 Wh L^–1. Furthermore, the electrodes demonstrated excellent cycling stability, retaining 90% capacity after 10,000 cycles in 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF₄). In contrast to aqueous-based electrolytes, the latter allows the cell to operate in wider voltage window of 3.5 V. In addition to the above, the synthesis is scalable, opening the capability for real-life applications. All in all, these findings highlight the potential use of G-Npyr as a high-performance, scalable electrode material for next-generation supercapacitors.