Efficient metal-free supercapacitor based on graphene oxide derived from waste rice

Abstract

In the present study, a new eco-friendly process has been developed for the synthesis of porous graphene oxide. First, waste rice bead has been heated for making char and then this char has been utilized for the synthesis of porous graphene oxide. Atomic force microscopic study reveals that the thickness of the graphene oxide nanosheets was ~4 ​nm. Further, electron microscopy study of graphene oxide confirms the formation of nanosheets of size ~4 ​μm containing pores of ~ 3–10 ​nm diameter. The as-prepared graphene oxide has been drop casted over glassy carbon electrode. The electrochemical supercapacitor study shows 158.6 ​F/g specific capacitance at 1 A/g discharge current. The life cycle of prepared electrode material shows ~93% capacitance retention at 3 A/g discharge current.

Keywords

• Energy storage
• Supercapacitors
• Waste rice
• Graphene oxide (GO)