Optimized time dependent exfoliation of graphite for fabrication of Graphene/GO/GrO nanocomposite based...

High capacitance devices (Supercapacitors) fabricated using two-dimensional materials such as Graphene and its composites are attracting great attention of the research community, recently. Synthesis of 2D materials and their composites with high quality is desirable for the fabrication of 2D materials-based supercapacitors. Ultrasonic Assisted Liquid Phase Exfoliation (UALPE) is one of the widely used techniques for the synthesis of graphene. In this article, we report the effect of variation in sonication time on the exfoliation of graphite powder to extract a sample with optimal properties well suited for supercapacitors applications. Three different graphite powders (hereafter termed as sample A, sample B, and sample C) were sonicated for duration of 24 h, 48 h and 72 h at 60 °C. The exfoliation of graphite powder into graphene, GO and GrO was studied using XRD and RAMAN. AFM and SEM were further used to examine the layered structure of the synthesized nanocomposite. UV-visible spectroscopy and cyclic voltammetery were used to measure the band gaps, and capacitive behavior of the samples. Sample B exhibited a remarkable specific capacitance of 534.53 F/g with charge specific capacity of 530.1 C/g at 1 A/g and energy density of 66 kW/kg. Power density varied 0.75 kWh/kg to 7.5 kWh/kg for a variation in current density from 1 to 10 A/g. Sample B showed capacitive retention of 94%, the lowest impedance and highest degree of exfoliation and conductivity as compared to the other two samples.