Characterization and electrochemical studies of MWCNTs decorated with Ag nanoparticles through pulse reversed current electrodeposition using a deep eutectic solvent for energy storage applications

Carbon nanotubes (CNTs) are receiving special attention due to their remarkable thermal, electrical, and mechanical properties. The present work reports an innovative synthesis procedure to decorate MWCNTs with silver nanoparticles (Ag-NPs) via pulsed reverse deposition technique using a deep eutectic solvent (DES) based on choline chloride and glycerol as an electrolyte at room temperature, not requiring any previous surface modification of MWCNTs. MWCNTs decorated with Ag-NPs disclose a significant enhancement of their electrochemical performance as demonstrated by the increase of electrode stability and specific capacitance. Electrochemical characterization of the composite material was performed using cyclic voltammetry and charge/discharge curves, achieving a specific capacitance up to 28.50 F. g−1, against 4.70 F. g−1 for the commercial MWCNTs in a three-electrode system. Retention of the specific capacitance up to 99% for the Ag-MWCNTs composites compared with a value of 78% for electrodes modified with commercial MWCNTs. The Ag-MWCNTs composites were characterized through SEM/EDX analysis, ultrahigh-resolution STEM, in which the Z – Contrast image was collected, and Raman analysis to prove the successful attachment of the Ag-NPs to the MWCNTs surface. AFM was performed to evaluate the conductivity of the composites.