Effect of cascaded centrifugal speed on scalability potential of few layer graphene via liquid phase exfoliation

The scale-up potential for producing high-quality few-layer graphene is essential for its effective integration into advanced industrial applications, including optoelectronics, supercapacitors, printable and flexible electronics, and biosensors. This paper investigates the effects of centrifugal speed on the exfoliation of bulk graphite powder into few-layer graphene nanosheets through the liquid-phase exfoliation technique. The liquid cascaded centrifugation method with various speeds of 3000, 5000, and 8000 rpm was used for the separation of graphene sheets with various lateral sizes and thicknesses. The exfoliated graphene nanosheets were characterized using a UV-vis spectrophotometer, Raman spectrometer, scanning electron microscope (SEM), atomic force microscopy (AFM), X-ray diffractometer (XRD), and transmission electron microscope (TEM). The percentage yield ranged from 4.57 to 8.34%. The AFM and Raman confirmed the existence of few-layer nanosheets (5 to 12 layers) of graphene, while the existence of average lateral sizes of 0.53 μm at 3000 rpm was obtained, with the smallest sizes of 0.38 μm at 8000 rpm. The graphene sample was shown to exhibit a highly crystalline graphitic structure. This method offers a practical, scalable path towards manufacturing high-quality few-layer graphene nanosheets (5 to 12 layers) without the use of hazardous intercalation reagents, thus showing great potential for industrial-scale use.