Laser-Induced Nitrogen-doped Graphene for High-Performance Flexible Supercapacitors

In recent years, with development of electronic devices in the direction of miniaturization, portability and multifunctionality, higher requirements are put forward for supercapacitors, including ultra-thinness, flexibility, high electrochemical performance, scale-up capability, and low cost. Among various electrode materials developed for supercapacitors, laser-induced graphene (LIG) is a promising material because of its simple operation, no mask, high efficiency and scalability. However, the electrochemical performance of LIG needs to be further improved. Here, a one-step method has reported for fabricating laser-induced nitrogen-doped graphene (LING) by using a laser direct writing technology. A three-dimensional (3D) structure of LING was obtained by engraving the surface of urea-containing polyimide (PI) film with a pulsed laser. Considering the synergistic effect of high concentration nitrogen doping and 3D porous structure, LING-based thin-film supercapacitor showed an ultra-high volumetric capacitance over 1260 mF/cm
³
, much higher than that of LIG, and no significant attenuation was observed after 100,000 cycles. Moreover, this method could prepare conductive lines and patterns on a flexible substrate with high efficiency and is expected to become an alternative method for preparing existing circuits or energy storage devices.