Single pot electrochemical synthesis of functionalized and phosphorus doped graphene nanosheets for supercapacitor applications

Facile synthesis of heteroatom doped graphene nanosheets is one of the recent trends in the development of energy storage materials like supercapacitors. Phosphorus doped graphene sheets (P-GNS) have been prepared using electrochemical method (EC), which is the most emerging technique for large scale synthesis. X-ray diffraction studies of as-electrochemically phosphorus doped graphene nanosheets (EC-P-GNS) synthesized show a shift towards lower 2 theta values due to functionalized graphene sheets. Scanning electron microscopy analysis of EC-P-GNS shows folded and twisted type graphene nanosheets and the average sheet thickness was measured to be 40 nm. High resolution-transmission electron microscopy depth profile confirms the presence of few layer transparent graphene with twisted type sheets. Fourier transform-infra red analysis of EC-P-GNS confirms the presence of functional groups in the doped graphene sheets. X-ray photoelectron microscopy analysis of EC-P-GNS shows 0.68 % phosphorus atomic doping which confirms the P-doping in graphene nanosheets. The electrochemical performance was analyzed using EC-P-GNS and shows good cycle performance compared to graphite. The electrochemical charge/discharge curves of EC-P-GNS give a high specific capacitance (Csp) of 290 F g(-1) along with high energy density 43.75 Wh kg(-1). Based on the above merits including higher Csp, we hope that our EC-P-GNS would be a promising material for super capacitors. Further, the prepared single pot electrochemical anodic erosion strategy provides easy scale up for all heteroatoms doped graphene nanosheets synthesis.