Facile Synthesis of Sulfur Doped Graphene Quantum Dots for High Performance Supercapacitor Applications

A comprehensive study of an efficient pseudocapacitor electrode material has been done for sulfur doped graphene quantum dots (S-GQDs). Two different electrode materials were prepared by selecting two different sulfur containing powders that is, MgSO4.7H2O (sample-I), CuSO4.7H2O (sample-II), as source material by using the facile hydrothermal method. HRTEM results show that sample-II (∼5–20 nm) had a small size in comparison to sample-I (∼10–50 nm). The measured specific capacitance for sample-II was found to be 133 Fg−1 at 0.1 mAg−1 is much higher than in sample-II due to enhancement in electrical conductivity and improvement in the electron transfer between electrodes and electrolyte.