Synthesis of a porous interconnected nitrogen-doped graphene aerogel matrix incorporated with ytterbium oxide nanoparticles and its application in superior symmetric supercapacitors

Interconnected graphene aerogels (IC:GA) and their composites with transition metal oxide nanoparticles are attracting increasing research interest for fabrication of supercapacitors. In this study, for the first time, we have incorporated ytterbium oxide nanoparticles (Yb2O3 NPs) to a nitrogen doped-interconnected graphene aerogels (N-IC:GA) matrix through a facial one-step hydrothermal method and by using p-phenylenediamine (PPD) as an interconnector and a source of nitrogen. In this porous network, graphene nanosheets are present with very low thickness of about 5–9 nm. The electrochemical performance of the nanocomposite was investigated by cyclic voltammetry (CV), galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS) and continuous cyclic voltammetry (CCV). The obtained Yb2O3/N-IC:GA nanocomposite was tested as a symmetric capacitor which exhibited a specific capacitance of 321 Fg−1 at a current density of 0.5 A g−1, a high energy density of 25 Wh Kg−1, an excellent cycle life for voltage values up to 1.5 V, and a capacitance retention of 98.4% after 4000 cycles in an environment-friendly aqueous electrolyte of 1 M Na2SO4. Moreover, Yb2O3/N-IC:GA proved to be highly capable because the delivered specific capacitance at a current density of 16 A g−1 retained 53.4% of its value at 0.5 A g−1. [Display omitted] •For the first time, ytterbium oxide nanoparticles were incorporated to N-IC:GA in a simple synthetic manner.•Due to the utilizing of Yb2O3 and PPD, the performance of graphene aerogel-based supercapacitor was significantly upgraded.•The synthesized nanocomposite exhibits a high energy density of 25 Wh kg−1 at a power density of 375 W kg−1.