Sonochemical preparation of a ytterbium oxide/reduced graphene oxide nanocomposite for supercapacitors with enhanced capacitive performance

Decoration of graphene with different nanostructures can result in fundamental advancements in versatile technologies, especially in the fast growing fields of catalysts, sensors and energy storage. In this study, we have synthesized ytterbia (Yb₂O₃) nanoparticles through a facile sonochemical process. These nanoparticles have been anchored on the surface of reduced graphene oxide (RGO) via a self-assembly approach. We investigated the supercapacitive behavior of the nanocomposites as electrode materials with cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy techniques. These nanocomposites exhibit a specific capacitance of 240 F g^-1 in 0.5 M Na₂SO₄ electrolyte at a scan rate of 2 mV s^-1. Additionally, the specific capacitance of the nanocomposite electrode is 222 F g^-1 at the current density of 1 A g^-1 in the galvanostatic charge-discharge measurements. These excellent electrochemical performances can stem from the synergism between the properties of Yb₂O₃ nanoparticles and RGO sheets, high charge mobility of them and good flexibility of the graphene sheets. Furthermore, the nanocomposite electrode presents excellent cycling durability with 96.5% specific capacitance restored after 4000 cycles. Our present work introduces a novel procedure to fabricate Yb₂O₃/RGO nanocomposites as a promising candidate in high performance energy applications.