Influence of high-shear exfoliation and the stabilizer on the formation of exfoliated graphene nanosheets and its supercapacitive performances

Abstract

Despite the extensive research on the preparation of graphene nanosheets, there is no suitable and optimized procedure for the large-scale production of 'defect-free' graphene monolayers. In addition, there is only a few works on the eco-friendly shear exfoliation of graphite using water as the solvent. However, no work has been reported on optimizing the critical parameters such as rotation speed and time duration (rpm) of shear homogenizer and concentration of stabilizer that determine the quality of graphene nanosheets. In this paper, an eco-friendly and scalable approach to prepare graphene nanosheets from natural graphite flakes using a high-speed shear homogenizer and sodium dodecyl sulfate (SDS) as an ionic stabilizer has been reported. As a result, the obtained efficiency of exfoliated graphene corresponding to the optimized condition is found to be 89%. Later, the exfoliated graphene is characterized by both physical characterization (i.e., Raman spectroscopy and FE-SEM) and electrochemical characterization. The electrochemical analysis reveals that the prepared graphene nanosheets exhibit a specific capacitance of 60.24 Fg⁻¹. This method is simple, inexpensive, environmentally friendly, and easy to scale up.