Brominated graphene oxide: A novel synthesis approach for enhanced performance in energy storage applications

Abstract

Graphene halides, a class of graphene derivatives with covalently attached halogens, represent an exciting category of two-dimensional materials with remarkable physical and chemical characteristics. This study explores the energy storage properties of electrodes based on bromine and oxygen intercalated graphite, synthesized using a strong oxidizing agent and hydro bromic acid at room temperature. A novel approach was employed by utilizing piranha and hydro bromic acid as an alternative to meta-chloroperoxybenzoic acid and hydrogen peroxide (m-CPBA and H2O2) for post-oxidation, significantly enhancing oxygen and bromine simultaneously on the graphite surface. The Br-GO material was extensively characterized using PXRD, XPS, BET, Raman spectroscopy, SEM, and FT-IR, confirming the successful intercalation of bromine and different oxygen moieties onto the graphite surface. Electrochemical characteristics of the Br-GO electrode were analysed using CV, EIS, and GCD techniques with 6 M KOH as the electrolytic solution. These results indicated that the Br-GO electrode exhibited quasi-rectangular capacitance behaviour, achieving a high specific capacitance of 371.4 F g⁻¹ at a current density of 1 A g⁻¹ and maintaining excellent cycling stability with only 9 % capacitance loss over 5000 cycles. This enhanced performance can be obtained due to improved ionic mobility facilitated by the bromine and oxygen content on the graphite surface. Additionally, the iodinated graphene derivative achieved a bromine content of 3.2 wt%. The proposed synthesis route offers a straightforward, scalable and efficient one-pot synthesis for producing brominated graphene oxide, demonstrating significant potential for use in supercapacitors applications.