Facile Preparation of Amino Edge Functionalized N-doped Holey Graphene for Room Temperature Curable Ink Formulation Suitable for Flexible Electronics and Energy Storage Applications

Flexible conducting wires are highly relevant nowadays due to their possible integration into various electronic gadgets, where energy storage devices are also needed. Here a material composed of N-doped holey graphene with aromatic primary amine groups at the edges (N-doped holey graphene amine) takes the dual role of conducting wire and electrode for supercapacitors. A facile ball-milling of graphite with the N-containing milling agent 1-naphthylamine followed by high-temperature treatment led to the formation of N-doped holey graphene as evident from the material characterization using transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, ¹³C NMR spectroscopy, atomic force microscopy and elemental analysis. In addition to pyridinic, pyrolytic, and graphitic N, the NMR spectrum and XPS confirm the presence of -NH₂ attached to aromatic carbon. The graphene inks prepared at different temperatures including room temperature displayed variable conductivity suitable for the required applications; the sample treated at 250 °C was also used as an electrode material for supercapacitors. An areal capacitance of 12.33 mF/cm² at a current density of 0.06 mA/cm² is displayed by the graphene ink supercapacitor device together with an energy density of 1.71 μWh/cm². A power density of 500 μW/cm² at a current density of 1 mA/cm² is displayed, and at 0.5 mA/cm², the device retained 100% of its capacitance after 5000 continuous charge–discharge cycles.