Fabrication of flexible nitrogen-doped graphene micro-supercapacitors by laser-induced self-made precursors

With the wide application of portable wearable devices, a variety of electronic energy storage devices, including micro-supercapacitors (MSCs), have attracted wide attention. Laser-induced graphene (LIG) is widely used as electrode material for MSCs because of its large porosity and specific surface area. To further improve the performance of MSCs, it is an effective way to increase the specific surface area and the number of internal active sites of laser-induced graphene electrode materials. In this paper, N-doped polyimide/polyvinyl alcohol (PVA) as precursor was used to achieve in situ doping of nitrogen atoms in laser-induced graphene by laser irradiation. Through the addition of N atoms, nitrogen-doped laser-induced three-dimensional porous graphene (N-LIG) exhibits large specific surface area, many active sites, and good wettability all of which are favorable conditions for enhancing the capacitive properties of laser-induced graphene. After assembly with PVA/H₂SO₄ as gel electrolyte, the high surface capacitance of the MSC device with N-LIG as electrode material is 16.57 mF cm⁻² at the scanning rate of 5 mV s⁻¹, which is much higher than the 2.89 mF cm⁻² of the MSC device with LIG as electrode material. In addition, MSC devices with N-LIG as electrode materials have shown excellent cyclic stability and flexibility in practical tests, so they have a high application prospect in the field of flexible wearable microelectronics.