Electroactive Anthraquinone-Grafted Reduced Graphene Oxide as a Versatile Electrode for Affordable Supercapacitors and Lithium-Ion Batteries

High Resolution Image Download MS PowerPoint Slide Hybrid electrodes that reconcile diffusion and surface-controlled redox are essential for high-power and durable storage. Herein, we engineer reduced graphene oxide (rGO) by covalently grafting anthraquinone (AQ) motifs to create dual-function materials that operate efficiently in supercapacitors and lithium-ion batteries (LIBs). Two precursors─2-aminoanthraquinone (AAQ) and 2-(bis(4-aminophenyl)amino)anthracene-9,10-dione (APAAD)─were coupled to graphene oxide and chemically reduced to yield AQ-rGO and APAD-rGO . FT-IR and X-ray photoelectron spectroscopy confirm amide linkages, while powder X-ray diffraction shows enlarged interlayer spacings of 0.930 ( AQ-rGO ) and 1.280 nm ( APAD-rGO ). Electrochemical analyses reveal pseudocapacitive behavior with medium-dependent kinetics. In aqueous supercapacitors, cyclic-voltammetry b -values of 0.553 ( AQ-rGO ) and 0.526 ( APAD-rGO ) indicate diffusion-influenced charge storage. In LIB system, the b -value increases to 0.85 and 0.82, respectively, with capacitive fractions of ∼77% and ∼69% at 0.5–1.0 mV s –1, reflecting accelerated surface redox and shortened ion paths. Temperature-dependent impedance spectroscopy gives activation energies of 32.7 kJ mol –1 ( AQ-rGO ) and 26.7 kJ mol –1 ( APAD-rGO ), consistent with galvanostatic intermittent titration analysis, showing higher Li + diffusivity in APAD-rGO . Furthermore, the electrochemical performance mirrors these kinetics. As a supercapacitor, the anthraquinone-grafted rGO demonstrates a specific capacitance of 60 F g –1 up to 70 cycles under a scan rate of 5 mV s –1 . As a LIB cathode, APAD-rGO delivers 129.7 mA h g –1 at 50 mA g –1, maintains a rate capability from 100 to 2000 mA g –1, and sustains 1000-cycle durability with excellent stability. This cathode outperforms the rGO cathode with 45 mA h g –1 under a 50 mA g –1 current density. As anodes, AQ-rGO and APAD-rGO, respectively, provide initial capacities of 403 and 340 mA h g –1, stabilize at 345 and 283 mA h g –1 after 100 cycles, and operate up to 2000 mA g –1 with progressive activation. Overall, quinone grafting activates dense redox sites, tunes transport length scales, and bridges capacitive and diffusion storage in carbon frameworks.