Metal-Assisted Microwave Reduction of Graphene Oxide for High-Performance Supercapacitors

Abstract

Supercapacitors are critical in the development of new energy technologies. Graphene-based supercapacitor research has been widespread, but existing reduction methods such as thermal reduction and chemical reduction have issues related to high energy consumption and environmental unfriendliness. In this study, we introduce a solvent-free one-step microwave reduction method for graphene oxide, utilized as electrodes in the fabrication of supercapacitors. The process involves mixing graphene oxide powder with iron or titanium, followed by reduction via microwave irradiation in a vacuum or inert environment. The generation of plasma through the interaction of metal and microwave enables reduced graphene oxide in low vacuum or inert environments. Electrochemical measurements were conducted using 1 M LiCl as the electrolyte. Remarkably, a maximum specific capacitance of 176 F g-1 was achieved at a current density of 1 A g-1. Furthermore, after 5000 charge and discharge cycles at the same current density, the capacitor maintained an impressive retention rate of 85.5 %, demonstrating excellent cycle stability. The supercapacitors fabricated through this method exhibited an energy density of 24.2 Wh kg-1 at a power density of 665.7 W kg-1. This breakthrough in supercapacitors provides a pathway to solve bottleneck issues of low energy depletion and environmental disadvantages.

Keywords: Microwave, Reduced graphene oxide, Supercapacitor, Solution-free