Industrially scalable exfoliated graphene nanoplatelets by high-pressure airless spray technique for high-performance supercapacitors

The significance of Graphene-based materials in various energy conversion and storage devices has been increasing due to their high surface area helps to enhance the multidimensional storage capability. Even though a significant amount of work has been done on graphene synthesis, there is still a need for an economical and environmentally friendly large-scale graphene synthesis method. This work demonstrates the large-scale production of high-quality Graphene Nanoplatelets (GnPs) by high-pressure spray exfoliation to develop high-performance supercapacitors. The high-pressure exfoliated GnPs were used to construct symmetric supercapacitors and studied their performance in organic and aqueous electrolytes. The pronounced rectangularity of cyclic voltammetry (CV) curves in both electrolytes indicates the charge storage is mainly by electrical double layer mechanisms. Retaining rectangularity at very high scan rates (>1000 mV/s) in both electrolytes signifies the excellent rate performance of high pressure exfoliated GnP based supercapacitors. The maximum specific capacitance of 26 F g⁻¹ in the organic electrolyte and 86 F g⁻¹ in the aqueous electrolyte was experimentally demonstrated, comparatively better than many other graphene-based device reports. The high capacitance and energy retention in the organic and aqueous electrolyte at very high current densities (>15 A g⁻¹) indicate the potential usage during the demand surge power supply of exfoliated GnPs for the commercialization of graphene-based supercapacitors.