Zolmitriptan-functionalized graphene oxide and its composite with [Bmim][FeCl4] ionic liquid and biochar derived from the pyrolysis of Heracleum Persicum for supercapacitor application

Graphene oxide (GO) based electrodes often exhibit poor electrochemical performance due to agglomeration. Here, GO was functionalized with the expired heteroatom-rich pharmaceutical compound of Zolmitriptan (ZOL-FGO) as a redox-active spacer to alleviate the mentioned issue. Next, to enhance the electrochemical performance, KOH-activated biochar derived from Heracleum Persicum seeds (HP) through pyrolysis (as a reaction medium) and 1-butyl-3-methylimidazolium tetrachloroferrrate ([Bmim][FeCl4]) ionic liquid (IL) (as a conductivity enhancer) were synthesized and physically composited with the ZOL-FGO. Evaluation of the electrochemical behavior of ZOL-FGO/HP/IL electrode in a three-electrode (3E) system revealed the hybrid supercapacitor nature and recorded a specific capacitance (Cs) of 522 F g−1 at 1 A g−1 and a Cs retention of 97.3% over 10,000 cycles at 8 A g−1. Moreover, the ZOL-FGO/HP/IL//ZOL-FGO/HP/IL electrode was designed and analyzed in the two-electrode (2E) system to determine its practicability. This electrode recorded a Cs of 245 F g−1 at 1 A g−1, a Cs retention of 95.3% over 10,000 cycles at 8 A g−1, and a power density of 900 W kg−1 at the energy density of 41.35 Wh kg−1. The results confirmed that the synergistic effect of the synthesized materials could be promising in constructing a high-performance hybrid supercapacitor.