Enhanced electrochemical properties of multiwalled carbon nanotubes modified with silver nanoparticles for energy storage application

This work reports an easy, straightforward, and cost-effective method to synthesize a composite material using multiwalled carbon nanotubes (MWCNTs) and silver nanoparticles (Ag NPs) for application as an electrode in supercapacitors. The objective of this work was to enhance the charge transfer mechanism in supercapacitor cells by introducing the conductive particles in the MWCNT framework. The pivotal studies, like scanning (SEM), and transmission (TEM) electron microscopy, X-ray diffraction (XRD), Raman, and X-ray photoelectron (XPS) spectroscopy confirmed the formation of the composite as well as a successful deposition of Ag NPs on MWCNT. The surface area of the composite was evaluated by using the N2 adsorption-desorption studies and it was found to be of the order of 358 m2 g-1. Electrochemical studies were performed using a two-electrode system. Magnesium ion-based polymer gel electrolyte was used as an electrolyte material. The single electrode-specific capacitance was observed to be -31.9 F g-1 with power density and energy density values of -4.4 kW kg-1 and 1.2 Wh kg-1, respectively, at a current density of 0.46 A g-1. The cell was stable up to -5000 charge-discharge cycles with -96% of capacitance retention at the end of 5000 cycles.