High-performance symmetric supercapacitor based on new functionalized graphene oxide composites with pyrimidine nucleotide and nucleoside

Delivery of cytidine triphosphate (CTP) as pyrimidine nucleotide and Cytarabine or arabinosylcytosine (Ara-C) as pyrimidine nucleoside onto the surface of graphene oxide (GO) has led to the fabrication of effective composites of functionalized graphene oxides (FGO-CTP and FGO-Ara-C). In the present study, we have compared FGO-CTP and FGO-Ara-C composites as active electrodes in a system with three electrodes for electrochemical measurement. Also, the as-prepared composites exhibited an ideal supercapacitive behavior in a symmetric capacitor. For the two electrode arrangement, a capacitance of 212F g−1, an energy density of 17.8 Wh kg−1 at 325 W kg−1, and an outstanding life cycling was achieved for the FGO-CTP electrode within a voltage window of 0–1.3 V in 1 M H2SO4 electrolyte, demonstrating greater electrochemical behavior compared to that of FGO-Ara-C electrode. In addition, the DFT calculations and charge density analysis resulted in more charge distribution on the GO layer of FGO-CTP than that of FGO-Ara-C, making it more effective as an electrode material for supercapacitors. Taking advantage of the facile synthesis method for introducing phosphate functional groups onto the surface of graphene oxide opens up an effective way for the fabrication of high-performance devices with large active surface area and high electrochemical ability in energy storage systems. Also, the assembled device expands the practical application areas of electrochemical energy storage devices significantly.