Moringa oleifera and its spent tea waste composites as sustainable anode candidates for energy storage applications: Morphological and electrochemical performance studies

Abstract

Activated carbons of husk of Moringa bark (Mo) and its spent tea waste composites (Stw) (Mo-T1 —T4) are synthesized, characterized for structure and morphology, and investigated for their anode candidacy in supercapacitor and OER applications by cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronopotentiometry (galvanostatic charge/discharge; GCD), electrochemical impedance spectroscopy (EIS), and chronoamperometry (controlled potential electrolysis; CPE). Electrochemical studies for supercapacitor application reveal Mo-T1 and then Mo the best anode candidates amongst others. With high specific capacitance of 211.8 Fg-1 (CV@ 10 mVs-1), and 231.4 Fg-1 (GCD@ 0.5Ag-1), greater cyclic stability (93% capacitance retention), greater discharging time (324s @ 0.5Ag-1), and low solution resistance (1.67 Ω), Mo-T1 is not only proving to be the best anode candidate amongst studied materials but also these values were found greater/or comparable with various recently reported biomass derived anode materials for supercapacitor. The same materials (Mo-T1 and Mo) are found to be more efficient anode candidates for OER performance in water splitting with comparatively lower values of onset potential, overpotential, Tafel slopes and greater current stability at constant potential (1.65 V vs. RHE) during electrolysis. Overall findings indicate Mo-T1 and Mo the potential anode candidates for energy storage applications.